kallax

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 Go to latest Published: May 8, 2017 License: MIT Imports: 17 Imported by: 0

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Kallax is a PostgreSQL typesafe ORM for the Go language.

It aims to provide a way of programmatically write queries and interact with a PostgreSQL database without having to write a single line of SQL, use strings to refer to columns and use values of any type in queries.

For that reason, the first priority of kallax is to provide type safety to the data access layer. Another of the goals of kallax is make sure all models are, first and foremost, Go structs without having to use database-specific types such as, for example, sql.NullInt64. Support for arrays of all basic Go types and all JSON and arrays operators is provided as well.

Contents

Installation

The recommended way to install kallax is:

go get -u gopkg.in/src-d/go-kallax.v1/...

kallax includes a binary tool used by go generate, please be sure that $GOPATH/bin is on your $PATH

Usage

Imagine you have the following file in the package where your models are.

package models

type User struct {
        kallax.Model         `table:"users"`
        ID       kallax.ULID `pk:""`
        Username string
        Email    string
        Password string
}

Then put the following on any file of that package:

//go:generate kallax gen

Now all you have to do is run go generate ./... and a kallax.go file will be generated with all the generated code for your model.

If you don't want to use go generate, even though is the preferred use, you can just go to your package and run kallax gen yourself.

Excluding files from generation

Sometimes you might want to use the generated code in the same package it is defined and cause problems during the generation when you regenerate your models. You can exclude files in the package by changing the go:generate comment to the following:

//go:generate kallax gen -e file1.go -e file2.go

Define models

A model is just a Go struct that embeds the kallax.Model type. All the fields of this struct will be columns in the database table.

A model also needs to have one (and just one) primary key. That is whatever field of the struct with the struct tag pk, which can be pk:"" for a non auto-incrementable primary key or pk:"autoincr" for one that is auto-incrementable. More about primary keys is discussed at the primary keys section.

First, let's review the rules and conventions for model fields:

  • All the fields with basic types or types that implement sql.Scanner and driver.Valuer will be considered a column in the table of their matching type.
  • Arrays or slices of types mentioned above will be treated as PostgreSQL arrays of their matching type.
  • Fields that are structs (or pointers to structs) or interfaces not implementing sql.Scanner and driver.Valuer will be considered as JSON. Same with arrays or slices of types that follow these rules.
  • Fields that are structs (or pointers to structs) with the struct tag kallax:",inline" or are embedded will be considered inline, and their fields would be considered as if they were at the root of the model.
  • All pointer fields are nullable by default. That means you do not need to use sql.NullInt64, sql.NullBool and the likes because kallax automatically takes care of that for you. WARNING: all JSON and sql.Scanner implementors will be initialized with new(T) in case they are nil before they are scanned.
  • By default, the name of a column will be the name of the struct field converted to lower snake case (e.g. UserName => user_name, UserID => user_id). You can override it with the struct tag kallax:"my_custom_name".
  • Slices of structs (or pointers to structs) that are models themselves will be considered a 1:N relationship. Arrays of models are not supported by design.
  • A struct or pointer to struct field that is a model itself will be considered a 1:1 relationship.
  • For relationships, the foreign key is assumed to be the name of the model converted to lower snake case plus _id (e.g. User => user_id). You can override this with the struct tag fk:"my_custom_fk".
  • For inverse relationship, you need to use the struct tag fk:",inverse". You can combine the inverse with overriding the foreign key with fk:"my_custom_fk,inverse". In the case of inverses, the foreign key name does not specify the name of the column in the relationship table, but the name of the column in the own table. The name of the column in the other table is always the primary key of the other model and cannot be changed for the time being.
  • Foreign keys do not have to be in the model, they are automagically managed underneath by kallax.

Kallax also provides a kallax.Timestamps struct that contains CreatedAt and UpdatedAt that will be managed automatically.

Let's see an example of models with all these cases:

type User struct {
        kallax.Model       `table:"users"`
        kallax.Timestamps
        kallax.ID int64    `pk:"autoincr"`
        Username  string
        Password  string
        Emails    []string
        // This is for demo purposes, please don't do this
        // 1:N relationships load all N rows by default, so
        // only do it when N is small.
        // If N is big, you should probably be querying the posts
        // table instead.
        Posts []*Post `fk:"poster_id"`
}

type Post struct {
        kallax.Model      `table:"posts"`
        kallax.Timestamps
        ID       int64    `pk:"autoincr"`
        Content  string   `kallax:"post_content"`
        Poster   *User    `fk:"poster_id,inverse"`
        Metadata Metadata `kallax:",inline"`
}

type Metadata struct {
        MetadataType MetadataType
        Metadata map[string]interface{} // this will be json
}

Struct tags

Tag Description Can be used in
table:"table_name" Specifies the name of the table for a model. If not provided, the name of the table will be the name of the struct in lower snake case (e.g. UserPreference => user_preference) embedded kallax.Model
pk:"" Specifies the field is a primary key any field with a valid identifier type
pk:"autoincr" Specifies the field is an auto-incrementable primary key any field with a valid identifier type
kallax:"column_name" Specifies the name of the column Any model field that is not a relationship
kallax:"-" Ignores the field and does not store it Any model field
kallax:",inline" Adds the fields of the struct field to the model. Column name can also be given before the comma, but it is ignored, since the field is not a column anymore Any struct field
fk:"foreign_key_name" Name of the foreign key column Any relationship field
fk:",inverse" Specifies the relationship is an inverse relationship. Foreign key name can also be given before the comma Any relationship field

Primary keys

Primary key types need to satisfy the Identifier interface. Even though they have to do that, the generator is smart enough to know when to wrap some types to make it easier on the user.

The following types can be used as primary key:

  • int64
  • uuid.UUID
  • kallax.ULID: this is a type kallax provides that implements a lexically sortable UUID. You can store it as uuid like any other UUID, but internally it's an ULID and you will be able to sort lexically by it.

If you need another type as primary key, feel free to open a pull request implementing that.

Known limitations

  • Only one primary key can be specified and it can't be a composite key.

Model constructors

Kallax generates a constructor for your type named New{TypeName}. But you can customize it by implementing a private constructor named new{TypeName}. The constructor generated by kallax will use the same signature your private constructor has. You can use this to provide default values or construct the model with some values.

If you implement this constructor:

func newUser(username, password string, emails ...string) (*User, error) {
        if username != "" || len(emails) == 0 || password != "" {
                return errors.New("all fields are required")
        }

        return &User{Username: username, Password: password, Emails: emails}
}

Kallax will generate one with the following signature:

func NewUser(username string, password string, emails ...string) (*User, error)

IMPORTANT: if your primary key is not auto-incrementable, you should set an ID for every model you create in your constructor. Or, at least, set it before saving it. Inserting, updating, deleting or reloading an object with no primary key set will return an error.

If you don't implement your own constructor it's ok, kallax will generate one for you just instantiating your object like this:

func NewT() *T {
        return new(T)
}

Model events

Events can be defined for models and they will be invoked at certain times of the model lifecycle.

  • BeforeInsert: will be called before inserting the model.
  • BeforeUpdate: will be called before updating the model.
  • BeforeSave: will be called before updating or inserting the model. It's always called before BeforeInsert and BeforeUpdate.
  • BeforeDelete: will be called before deleting the model.
  • AfterInsert: will be called after inserting the model. The presence of this event will cause the insertion of the model to run in a transaction. If the event returns an error, it will be rolled back.
  • AfterUpdate: will be called after updating the model. The presence of this event will cause the update of the model to run in a transaction. If the event returns an error, it will be rolled back.
  • AfterSave: will be called after updating or inserting the model. It's always called after AfterInsert and AfterUpdate. The presence of this event will cause the operation with the model to run in a transaction. If the event returns an error, it will be rolled back.
  • AfterDelete: will be called after deleting the model. The presence of this event will cause the deletion to run in a transaction. If the event returns an error, it will be rolled back.

To implement these events, just implement the following interfaces. You can implement as many as you want:

Example:

func (u *User) BeforeSave() error {
        if u.Password == "" {
                return errors.New("cannot save user without password")
        }

        if !isCrypted(u.Password) {
                u.Password = crypt(u.Password)
        }
        return nil
}

Kallax generated code

Kallax generates a bunch of code for every single model you have and saves it to a file named kallax.go in the same package.

For every model you have, kallax will generate the following for you:

  • Internal methods for your model to make it work with kallax and satisfy the Record interface.
  • A store named {TypeName}Store: the store is the way to access the data. A store of a given type is the way to access and manipulate data of that type. You can get an instance of the type store with New{TypeName}Store(*sql.DB).
  • A query named {TypeName}Query: the query is the way you will be able to build programmatically the queries to perform on the store. A store only will accept queries of its own type. You can create a new query with New{TypeName}Query(). The query will contain methods for adding criteria to your query for every field of your struct, called FindBys. The query object is not immutable, that is, every condition added to it, changes the query. If you want to reuse part of a query, you can call the Copy() method of a query, which will return a query identical to the one used to call the method.
  • A resultset named {TypeName}ResultSet: a resultset is the way to iterate over and obtain all elements in a resultset returned by the store. A store of a given type will always return a result set of the matching type, which will only return records of that type.
  • Schema of all the models containing all the fields. That way, you can access the name of a specific field without having to use a string, that is, a typesafe way.

Model schema

Automatic schema generation and migrations

Automatic CREATE TABLE for models and migrations is not yet supported, even though it will probably come in future releases.

Use schema

A global variable Schema will be created in your kallax.go, that contains a field with the name of every of your models. Those are the schemas of your models. Each model schema contains all the fields of that model.

So, to access the username field of the user model, it can be accessed as:

Schema.User.Username

Manipulate models

For all of the following sections, we will assume we have a store store for our model's type.

Insert models

To insert a model we just need to use the Insert method of the store and pass it a model. If the primary key is not auto-incrementable and the object does not have one set, the insertion will fail.

user := NewUser("fancy_username", "super_secret_password", "foo@email.me")
err := store.Insert(user)
if err != nil {
        // handle error
}

If our model has relationships, they will be saved (note: saved as in insert or update) as well. The relationships of the relationships will not, though. Relationships are only saved with one level of depth.

user := NewUser("foo")
user.Posts = append(user.Posts, NewPost(user, "new post"))

err := store.Insert(user)
if err != nil {
        // handle error
}

If there are any relationships in the model, both the model and the relationships will be saved in a transaction and only succeed if all of them are saved correctly.

Update models

To insert a model we just need to use the Update method of the store and pass it a model. It will return an error if the model was not already persisted or has not an ID.

user := FindLast()
rowsUpdated, err := store.Update(user)
if err != nil {
        // handle error
}

By default, when a model is updated, all its fields are updated. You can also specify which fields to update passing them to update.

rowsUpdated, err := store.Update(user, Schema.User.Username, Schema.User.Password)
if err != nil {
        // handle error
}

If our model has relationships, they will be saved (note: saved as in insert or update) as well. The relationships of the relationships will not, though. Relationships are only saved with one level of depth.

user := FindLastPoster()
rowsUpdated, err := store.Update(user)
if err != nil {
        // handle error
}

If there are any relationships in the model, both the model and the relationships will be saved in a transaction and only succeed if all of them are saved correctly.

Save models

To save a model we just need to use the Save method of the store and pass it a model. Save is just a shorthand that will call Insert if the model is not yet persisted and Update if it is.

updated, err := store.Save(user)
if err != nil {
        // handle error
}

if updated {
        // it was updated, not inserted
}

If our model has relationships, they will be saved as well. The relationships of the relationships will not, though. Relationships are only saved with one level of depth.

user := NewUser("foo")
user.Posts = append(user.Posts, NewPost(user, "new post"))

updated, err := store.Save(user)
if err != nil {
        // handle error
}

If there are any relationships in the model, both the model and the relationships will be saved in a transaction and only succeed if all of them are saved correctly.

Delete models

To delete a model we just have to use the Delete method of the store. It will return an error if the model was not already persisted.

err := store.Delete(user)
if err != nil {
        // handle error
}

Relationships of the model are not automatically removed using Delete.

For that, specific methods are generated in the store of the model.

For one to many relationships:

// remove specific posts
err := store.RemovePosts(user, post1, post2, post3)
if err != nil {
        // handle error
}

// remove all posts
err := store.RemovePosts(user)

For one to one relationships:

// remove the thing
err := store.RemoveThing(user)

Query models

Simple queries

To perform a query you have to do the following things:

  • Create a query
  • Pass the query to Find, FindOne, MustFind or MustFindOne of the store
  • Gather the results from the result set, if the used method was Find or MustFind
// Create the query
q := NewUserQuery().
        Where(kallax.Like(Schema.User.Username, "joe%")).
        Order(kallax.Asc(Schema.User.Username)).
        Limit(20).
        Offset(2)

rs, err := store.Find(q)
if err != nil {
        // handle error
}

for rs.Next() {
        user, err := rs.Get()
        if err != nil {
                // handle error
        }
}

Next will automatically close the result set when it hits the end. If you have to prematurely exit the iteration you can close it manually with rs.Close().

You can query just a single row with FindOne.

q := NewUserQuery().
        Where(kallax.Eq(Schema.User.Username, "Joe"))

user, err := store.FindOne(q)

By default, all columns in a row are retrieved. To not retrieve all of them, you can specify the columns to include/exclude. Take into account that partial records retrieved from the database will not be writable. To make them writable you will need to Reload the object.

// Select only Username and password
NewUserQuery().Select(Schema.User.Username, Schema.User.Password)

// Select all but password
NewUserQuery().SelectNot(Schema.User.Password)

Generated findbys

Kallax generates a FindBy for every field of your model for which it makes sense to do so. What is a FindBy? It is a shorthand to add a condition to the query for a specific field.

Consider the following model:

type Person struct {
        kallax.Model
        ID        int64     `pk:"autoincr"`
        Name      string
        BirthDate time.Time
        Age       int
}

Four FindBys will be generated for this model:

func (*PersonQuery) FindByID(...int64) *PersonQuery
func (*PersonQuery) FindByName(string) *PersonQuery
func (*PersonQuery) FindByBirthDate(kallax.ScalarCond, time.Time) *PersonQuery
func (*PersonQuery) FindByAge(kallax.ScalarCond, int) *PersonQuery

That way, you can just do the following:

NewPersonQuery().
        FindByAge(kallax.GtOrEq, 18).
        FindByName("Bobby")

instead of:

NewPersonQuery().
        Where(kallax.GtOrEq(Schema.Person.Age, 18)).
        Where(kallax.Eq(Schema.Person.Name, "Bobby"))

Why are there three different types of methods generated?

  • The primary key field is treated in a special way and allows multiple IDs to be passed, since searching by multiple IDs is a common operation.
  • Types that are not often searched by equality (integers, floats, times, ...) allow an operator to be passed to them to determine the operator to use.
  • Types that can only be searched by value (strings, bools, ...) only allow a value to be passed.

Count results

Instead of passing the query to Find or FindOne, you can pass it to Count to get the number of rows in the resultset.

n, err := store.Count(q)

Query with relationships

By default, no relationships are retrieved unless the query specifies so.

For each of your relationships, a method in your query is created to be able to include these relationships in your query.

One to one relationships:

// Select all posts including the user that posted them
q := NewPostQuery().WithPoster()
rs, err := store.Find(q)

One to one relationships are always included in the same query. So, if you have 4 one to one relationships and you want them all, only 1 query will be done, but everything will be retrieved.

One to many relationships:

// Select all users including their posts
// NOTE: this is a really bad idea, because all posts will be loaded
// if the N side of your 1:N relationship is big, consider querying the N store
// instead of doing this
// A condition can be passed to the `With{Name}` method to filter the results.
q := NewUserQuery().WithPosts(nil)
rs, err := store.Find(q)

To avoid the N+1 problem with 1:N relationships, kallax performs batching in this case. So, a batch of users are retrieved from the database in a single query, then all the posts for those users and finally, they are merged. This process is repeated until there are no more rows in the result. Because of this, retrieving 1:N relationships is really fast.

The default batch size is 50, you can change this using the BatchSize method all queries have.

NOTE: if a filter is passed to a With{Name} method we can no longer guarantee that all related objects are there and, therefore, the retrieved records will not be writable.

Reloading a model

If, for example, you have a model that is not writable because you only selected one field you can always reload it and have the full object. When the object is reloaded, all the changes made to the object that have not been saved will be discarded and overwritten with the values in the database.

err := store.Reload(user)

Reload will not reload any relationships, just the model itself. After a Reload the model will always be writable.

Querying JSON

You can query arbitrary JSON using the JSON operators defined in the kallax package. The schema of the JSON (if it's a struct, obviously for maps it is not) is also generated.

q := NewPostQuery().Where(kallax.JSONContainsAnyKey(
        Schema.Post.Metadata,
        "foo", "bar",
))

Transactions

To execute things in a transaction the Transaction method of the model store can be used. All the operations done using the store provided to the callback will be run in a transaction. If the callback returns an error, the transaction will be rolled back.

store.Transaction(func(s *UserStore) error {
        if err := s.Insert(user1); err != nil {
                return err
        }

        return s.Insert(user2)
})

The fact that a transaction receives a store with the type of the model can be a problem if you want to store several models of different types. Kallax has a method named StoreFrom that initializes a store of the type you want to have the same underlying store as some other.

store.Transaction(func(s *UserStore) error {
        var postStore PostStore
        kallax.StoreFrom(&postStore, s)

        for _, p := range posts {
                if err := postStore.Insert(p); err != nil {
                        return err
                }
        }

        return s.Insert(user)
})

Transaction can be used inside a transaction, but it does not open a new one, reuses the existing one.

Caveats

  • It is not possible to use slices or arrays of types that are not one of these types:
    • Basic types (e.g. []string, []int64) (except for rune, complex64 and complex128)
    • Types that implement sql.Scanner and driver.Valuer The reason why this is not possible is because kallax implements support for arrays of all basic Go types by hand and also for types implementing sql.Scanner and driver.Valuer (using reflection in this case), but without having a common interface to operate on them, arbitrary types can not be supported. For example, consider the following type type Foo string, using []Foo would not be supported. Know that this will fail during the scanning of rows and not in code-generation time for now. In the future, might be moved to a warning or an error during code generation. Aliases of slice types are supported, though. If we have type Strings []string, using Strings would be supported, as a cast like this ([]string)(&slice) it's supported and []string is supported.
  • time.Time and url.URL need to be used as is. That is, you can not use a type Foo being type Foo time.Time. time.Time and url.URL are types that are treated in a special way, if you do that, it would be the same as saying type Foo struct { ... } and kallax would no longer be able to identify the correct type.
  • time.Time fields will be truncated to remove its nanoseconds on Save, Insert or Update, since PostgreSQL will not be able to store them. PostgreSQL stores times with timezones as UTC internally. So, times will come back as UTC (you can use Local method to convert them back to the local timezone). You can change the timezone that will be used to bring times back from the database in the PostgreSQL configuration.
  • Multidimensional arrays or slices are not supported except inside a JSON field.

Migrations

Kallax can generate migrations for your schema automatically, if you want to. It is a process completely separated from the model generation, so it does not force you to generate your migrations using kallax.

Sometimes, kallax won't be able to infer a type or you will want a specific column type for a field. You can specify so with the sqltype struct tag on a field.

type Model struct {
        kallax.Model `table:"foo"`
        Stuff SuperCustomType `sqltype:"bytea"`
}

You can see the full list of default type mappings between Go and SQL.

Generate migrations

To generate a migration, you have to run the command kallax migrate.

kallax migrate --input ./users/ --input ./posts/ --output ./migrations --name initial_schema

The migrate command accepts the following flags:

Name Repeated Description Default
--name or -n no name of the migration file (will be converted to a_snakecase_name) migration
--input or -i yes every occurrence of this flag will specify a directory in which kallax models can be found. You can specify multiple times this flag if you have your models scattered across several packages required
--output or -o no destination folder where the migrations will be generated ./migrations

Every single migration consists of 2 files:

  • TIMESTAMP_NAME.up.sql: script that will upgrade your database to this version.
  • TIMESTAMP_NAME.down.sql: script that will downgrade your database to this version.

Additionally, there is a lock.json file where schema of the last migration is store to diff against the current models.

Run migrations

To run a migration you can either use kallax migrate up or kallax migrate down. up will upgrade your database and down will downgrade it.

These are the flags available for up and down:

Name Description Default
--dir or -d directory where your migrations are stored ./migrations
--dsn database connection string required
--steps or -s maximum number of migrations to run 0
--all migrate all the way up (only available for up
--version or -v final version of the database we want after running the migration. The version is the timestamp value at the beginning of migration files 0
  • If no --steps or --version are provided to down, they will do nothing. If --all is provided to up, it will upgrade the database all the way up.
  • If --steps and --version are provided to either up or down it will use only --version, as it is more specific.

Example:

kallax migrate up --dir ./my-migrations --dns 'user:pass@localhost:5432/dbname?sslmode=disable' --version 1493991142

Type mappings

Go type SQL type
kallax.ULID uuid
kallax.UUID uuid
kallax.NumericID serial on primary keys, bigint on foreign keys
int64 on primary keys serial
int64 on foreign keys and other fields bigint
string text
rune char(1)
uint8 smallint
int8 smallint
byte smallint
uint16 integer
int16 smallint
uint32 bigint
int32 integer
uint numeric(20)
int bigint
int64 bigint
uint64 numeric(20)
float32 real
float64 double
bool boolean
url.URL text
time.Time timestamptz
time.Duration bigint
[]T T'[] * where T' is the SQL type of type T
map[K]V jsonb
struct jsonb
*struct jsonb

Any other type must be explicitly specified.

Custom operators

You can create custom operators with kallax using the NewOperator and NewMultiOperator functions.

NewOperator creates an operator with the specified format. It returns a function that given a schema field and a value returns a condition.

The format is a string in which :col: will get replaced with the schema field and :arg: will be replaced with the value.

var Gt = kallax.NewOperator(":col: > :arg:")

// can be used like this:
query.Where(Gt(SomeSchemaField, 9000))

NewMultiOperator does exactly the same as the previous one, but it accepts a variable number of values.

var In = kallax.NewMultiOperator(":col: IN :arg:")

// can be used like this:
query.Where(In(SomeSchemaField, 4, 5, 6))

This function already takes care of wrapping :arg: with parenthesis.

Further customization

If you need further customization, you can create your own custom operator.

You need these things:

  • A condition constructor (the operator itself) that takes the field and the values to create the proper SQL expression.
  • A ToSqler that yields your SQL expression.

Imagine we want a greater than operator that only works with integers.

func GtInt(col kallax.SchemaField, n int) kallax.Condition {
        return func(schema kallax.Schema) kallax.ToSqler {
                // it is VERY important that all SchemaFields
                // are qualified using the schema
                return &gtInt{col.QualifiedName(schema), n}
        }
}

type gtInt struct {
        col string
        val int
}

func (g *gtInt) ToSql() (sql string, params []interface{}, err error) {
        return fmt.Sprintf("%s > ?", g.col), []interface{}{g.val}, nil
}

// can be used like this:
query.Where(GtInt(SomeSchemaField, 9000))

For most of the operators, NewOperator and NewMultiOperator are enough, so the usage of these functions is preferred over the completely custom approach. Use it only if there is no other way to build your custom operator.

Debug SQL queries

It is possible to debug the SQL queries being executed with kallax. To do that, you just need to call the Debug method of a store. This returns a new store with debugging enabled.

store.Debug().Find(myQuery)

This will log to stdout using log.Printf kallax: Query: THE QUERY SQL STATEMENT, args: [arg1 arg2].

You can use a custom logger (any function with a type func(string, ...interface{}) using the DebugWith method instead.

func myLogger(message string, args ...interface{}) {
        myloglib.Debugf("%s, args: %v", message, args)
}

store.DebugWith(myLogger).Find(myQuery)

Benchmarks

Here are some benchmarks against GORM and database/sql, which is one of the most popular ORMs for Go. In the future we might add benchmarks for some more complex cases and other available ORMs.

BenchmarkKallaxInsertWithRelationships-4   	     300	   4767574 ns/op	   19130 B/op	     441 allocs/op
BenchmarkRawSQLInsertWithRelationships-4   	     300	   4467652 ns/op	    3997 B/op	     114 allocs/op
BenchmarkGORMInsertWithRelationships-4     	     300	   4813566 ns/op	   34550 B/op	     597 allocs/op

BenchmarkKallaxInsert-4                    	     500	   3650913 ns/op	    3569 B/op	      85 allocs/op
BenchmarkRawSQLInsert-4                    	     500	   3530908 ns/op	     901 B/op	      24 allocs/op
BenchmarkGORMInsert-4                      	     300	   3716373 ns/op	    4558 B/op	     104 allocs/op

BenchmarkKallaxQueryRelationships/query-4  	    1000	   1535928 ns/op	   59335 B/op	    1557 allocs/op
BenchmarkRawSQLQueryRelationships/query-4  	      30	  44225743 ns/op	  201288 B/op	    6021 allocs/op
BenchmarkGORMQueryRelationships/query-4    	     300	   4012112 ns/op	 1068887 B/op	   20827 allocs/op

BenchmarkKallaxQuery/query-4               	    3000	    433453 ns/op	   50697 B/op	    1893 allocs/op
BenchmarkRawSQLQuery/query-4               	    5000	    368947 ns/op	   37392 B/op	    1522 allocs/op
BenchmarkGORMQuery/query-4                 	    2000	   1311137 ns/op	  427308 B/op	    7065 allocs/op

PASS
ok  	gopkg.in/src-d/go-kallax.v1/benchmarks	31.313s

As we can see on the benchmark, the performance loss is not very much compared to raw database/sql, while GORMs performance loss is very big and the memory consumption is way higher.

Source code of the benchmarks can be found on the benchmarks folder.

Notes:

  • Benchmarks were run on a 2015 MacBook Pro with i5 and 8GB of RAM and 128GB SSD hard drive running fedora 25.
  • Benchmark of database/sql for querying with relationships is implemented with a very naive 1+n solution. That's why the result is that bad.

Acknowledgements

  • Big thank you to the Masterminds/squirrel library, which is an awesome query builder used internally in this ORM.
  • lib/pq, the Golang PostgreSQL driver that ships with a ton of support for builtin Go types.
  • mattes/migrate, a Golang library to manage database migrations.

Contributing

Reporting bugs

Kallax is a code generation tool, so it obviously has not been tested with all possible types and cases. If you find a case where the code generation is broken, please report an issue providing a minimal snippet for us to be able to reproduce the issue and fix it.

Suggesting features

Kallax is a very opinionated ORM that works for us, so changes that make things not work for us or add complexity via configuration will not be considered for adding. If we decide not to implement the feature you're suggesting, just keep in mind that it might not be because it is not a good idea, but because it does not work for us or is not aligned with the direction we want kallax to be moving forward.

Running tests

For obvious reasons, an instance of PostgreSQL is required to run the tests of this package.

By default, it assumes that an instance exists at 0.0.0.0:5432 with an user, password and database name all equal to testing.

If that is not the case you can set the following environment variables:

  • DBNAME: name of the database
  • DBUSER: database user
  • DBPASS: database user password

License

MIT, see LICENSE

Documentation

Overview

Kallax is a PostgreSQL typesafe ORM for the Go language.

Kallax aims to provide a way of programmatically write queries and interact with a PostgreSQL database without having to write a single line of SQL, use strings to refer to columns and use values of any type in queries. For that reason, the first priority of kallax is to provide type safety to the data access layer. Another of the goals of kallax is make sure all models are, first and foremost, Go structs without having to use database-specific types such as, for example, `sql.NullInt64`. Support for arrays of all basic Go types and all JSON and arrays operators is provided as well.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrNonNewDocument non-new documents cannot be inserted
	ErrNonNewDocument = errors.New("kallax: cannot insert a non new document")
	// ErrNewDocument a new documents cannot be updated
	ErrNewDocument = errors.New("kallax: cannot updated a new document")
	// ErrEmptyID a document without ID cannot be used with Save method
	ErrEmptyID = errors.New("kallax: a record without id is not allowed")
	// ErrNoRowUpdate is returned when an update operation does not affect any
	// rows, meaning the model being updated does not exist.
	ErrNoRowUpdate = errors.New("kallax: update affected no rows")
	// ErrNotWritable is returned when a record is not writable.
	ErrNotWritable = errors.New("kallax: record is not writable")
	// ErrStop can be returned inside a ForEach callback to stop iteration.
	ErrStop = errors.New("kallax: stopped ForEach execution")
	// ErrInvalidTxCallback is returned when a nil callback is passed.
	ErrInvalidTxCallback = errors.New("kallax: invalid transaction callback given")
	// ErrNotFound is returned when a certain entity is not found.
	ErrNotFound = errors.New("kallax: entity not found")
	// ErrCantSetID is returned when a model is inserted and it does not have
	// neither an autoincrement primary key nor implements the IDSetter
	// interface.
	ErrCantSetID = errors.New("kallax: model does not have an auto incrementable primary key, it needs to implement IDSetter interface")
)
View Source 
var (
	// ErrManyToManyNotSupported is returned when a many to many relationship
	// is added to a query.
	ErrManyToManyNotSupported = errors.New("kallax: many to many relationships are not supported")
)
View Source 
var ErrRawScan = errors.New("kallax: result set comes from raw query, use RawScan instead")

ErrRawScan is an error returned when a the `Scan` method of `ResultSet` is called with a `ResultSet` created as a result of a `RawQuery`, which is not allowed.

View Source 
var ErrRawScanBatching = errors.New("kallax: cannot perform a raw scan on a batching result set")

ErrRawScanBatching is an error returned when the `RawScan` method is used with a batching result set.

Functions

func ApplyAfterEvents added in v0.13.0 

func ApplyAfterEvents(r Record, wasPersisted bool) error

ApplyAfterEvents calls all the update, insert or save after events of the record. Save events are always called after the insert or update event.

func ApplyBeforeEvents added in v0.13.0 

func ApplyBeforeEvents(r Record) error

ApplyBeforeEvents calls all the update, insert or save before events of the record. Save events are always called before the insert or update event.

func ColumnNames 

func ColumnNames(columns []SchemaField) []string

ColumnNames returns the names of the given schema fields.

func NewMultiOperator added in v1.2.0 

func NewMultiOperator(format string) func(SchemaField, ...interface{}) Condition

NewMultiOperator creates a new operator with a schema field and a variable number of values as arguments. The given format will define how the SQL is generated. You can put `:col:` wherever you want your column name to be on the format and `?` for the values, which will be automatically escaped. Example: `:col: IN :arg:`. You don't need to wrap the arg with parenthesis.

func NewOperator added in v1.2.0 

func NewOperator(format string) func(SchemaField, interface{}) Condition

NewOperator creates a new operator with two arguments: a schema field and a value. The given format will define how the SQL is generated. You can put `:col:` wherever you want your column name to be on the format and `?` for the value, which will be automatically escaped. Example: `:col: % :arg:`.

func RecordValues 

func RecordValues(record Valuer, columns ...string) ([]interface{}, error)

RecordValues returns the values of a record at the given columns in the same order as the columns.

func StoreFrom added in v1.1.0 

func StoreFrom(to, from GenericStorer)

StoreFrom sets the generic store of `from` in `to`.

func VirtualColumn added in v0.12.0 

func VirtualColumn(col string, r Record, id Identifier) sql.Scanner

VirtualColumn returns a sql.Scanner that will scan the given column as a virtual column in the given record.

Types

type AfterDeleter added in v0.13.0 

type AfterDeleter interface {
	// AfterDelete will do some operations after being deleted. If an error is
	// returned, it will cause the delete to be rolled back.
	AfterDelete() error
}

AfterDeleter will do some operations after being deleted.

type AfterInserter added in v0.13.0 

type AfterInserter interface {
	// AfterInsert will do some operations after being inserted. If an error is
	// returned, it will cause the insert to be rolled back.
	AfterInsert() error
}

AfterInserter will do some operations after being inserted.

type AfterSaver added in v0.13.0 

type AfterSaver interface {
	// AfterSave will do some operations after being inserted or updated. If an
	// error is returned, it will cause the insert or update to be rolled back.
	AfterSave() error
}

AfterSaver will do some operations after being inserted or updated.

type AfterUpdater added in v0.13.0 

type AfterUpdater interface {
	// AfterUpdate will do some operations after being updated. If an error is
	// returned, it will cause the update to be rolled back.
	AfterUpdate() error
}

AfterUpdater will do some operations after being updated.

type ArraySchemaField added in v0.13.0 

type ArraySchemaField interface {
	SchemaField
	// contains filtered or unexported methods
}

ArraySchemaField is an interface that defines if a field is a JSON array.

type BaseQuery 

type BaseQuery struct {
	// contains filtered or unexported fields
}

BaseQuery is a generic query builder to build queries programmatically.

func NewBaseQuery 

func NewBaseQuery(schema Schema) *BaseQuery

NewBaseQuery creates a new BaseQuery for querying the table of the given schema.

func (*BaseQuery) AddRelation 

func (q *BaseQuery) AddRelation(schema Schema, field string, typ RelationshipType, filter Condition) error

AddRelation adds a relationship if the given to the query, which is present in the given field of the query base schema. A condition to filter can also be passed in the case of one to many relationships.

func (*BaseQuery) BatchSize 

func (q *BaseQuery) BatchSize(size uint64)

BatchSize sets the batch size.

func (*BaseQuery) Copy 

func (q *BaseQuery) Copy() *BaseQuery

Copy returns an identical copy of the query. BaseQuery is mutable, that is why this method is provided.

func (*BaseQuery) GetBatchSize 

func (q *BaseQuery) GetBatchSize() uint64

GetBatchSize returns the number of rows retrieved per batch while retrieving 1:N relationships.

func (*BaseQuery) GetLimit 

func (q *BaseQuery) GetLimit() uint64

GetLimit returns the max number of rows to retrieve.

func (*BaseQuery) GetOffset 

func (q *BaseQuery) GetOffset() uint64

GetOffset returns the number of rows to skip.

func (*BaseQuery) Limit 

func (q *BaseQuery) Limit(n uint64)

Limit sets the max number of rows to retrieve.

func (*BaseQuery) Offset 

func (q *BaseQuery) Offset(n uint64)

Offset sets the number of rows to skip.

func (*BaseQuery) Order 

func (q *BaseQuery) Order(cols ...ColumnOrder)

Order adds the given order clauses to the list of columns to order the results by.

func (*BaseQuery) Schema added in v0.12.0 

func (q *BaseQuery) Schema() Schema

Schema returns the Schema of the query.

func (*BaseQuery) Select 

func (q *BaseQuery) Select(columns ...SchemaField)

Select adds the given columns to the list of selected columns in the query.

func (*BaseQuery) SelectNot 

func (q *BaseQuery) SelectNot(columns ...SchemaField)

SelectNot adds the given columns to the list of excluded columns in the query.

func (*BaseQuery) String 

func (q *BaseQuery) String() string

String returns the SQL generated by the query. If the query is malformed, it will return an empty string, as errors compiling the SQL are ignored.

func (*BaseQuery) Where 

func (q *BaseQuery) Where(cond Condition)

Where adds a new condition to filter the query. All conditions added are concatenated with "and". 

q.Where(Eq(NameColumn, "foo"))
q.Where(Gt(AgeColumn, 18))
// ... WHERE name = "foo" AND age > 18

type BaseResultSet added in v0.12.0 

type BaseResultSet struct {
	*sql.Rows
	// contains filtered or unexported fields
}

BaseResultSet is a generic collection of rows.

func NewResultSet 

func NewResultSet(rows *sql.Rows, readOnly bool, relationships []Relationship, columns ...string) *BaseResultSet

NewResultSet creates a new result set with the given rows and columns. It is mandatory that all column names are in the same order and are exactly equal to the ones in the query that produced the rows.

func (*BaseResultSet) Get added in v0.12.0 

func (rs *BaseResultSet) Get(schema Schema) (Record, error)

Get returns the next record in the schema.

func (*BaseResultSet) RawScan added in v0.12.0 

func (rs *BaseResultSet) RawScan(dest ...interface{}) error

RowScan copies the columns in the current row into the values pointed at by dest. The number of values in dest must be the same as the number of columns selected in the query.

func (*BaseResultSet) Scan added in v0.12.0 

func (rs *BaseResultSet) Scan(record Record) error

Scan fills the column fields of the given value with the current row.

type BaseSchema 

type BaseSchema struct {
	// contains filtered or unexported fields
}

BaseSchema is the basic implementation of Schema.

func NewBaseSchema 

func NewBaseSchema(table, alias string, id SchemaField, fks ForeignKeys, ctor RecordConstructor, autoIncr bool, columns ...SchemaField) *BaseSchema

NewBaseSchema creates a new schema with the given table, alias, identifier and columns.

func (*BaseSchema) Alias 

func (s *BaseSchema) Alias() string

func (*BaseSchema) Columns 

func (s *BaseSchema) Columns() []SchemaField

func (*BaseSchema) ForeignKey 

func (s *BaseSchema) ForeignKey(field string) (*ForeignKey, bool)

func (*BaseSchema) ID 

func (s *BaseSchema) ID() SchemaField

func (*BaseSchema) New added in v0.12.0 

func (s *BaseSchema) New() Record

func (*BaseSchema) Table 

func (s *BaseSchema) Table() string

func (*BaseSchema) WithAlias 

func (s *BaseSchema) WithAlias(field string) Schema

type BaseSchemaField 

type BaseSchemaField struct {
	// contains filtered or unexported fields
}

BaseSchemaField is a basic schema field with name.

func (*BaseSchemaField) QualifiedName 

func (f *BaseSchemaField) QualifiedName(schema Schema) string

func (BaseSchemaField) String 

func (f BaseSchemaField) String() string

type BatchingResultSet added in v0.12.0 

type BatchingResultSet struct {
	// contains filtered or unexported fields
}

BatchingResultSet is a result set that retrieves all the items up to the batch size set in the query. If there are 1:N relationships, it collects all the identifiers of those records, retrieves all the rows matching them in the table of the the N end, and assigns them to their correspondent to the record they belong to. It will continue doing this process until no more rows are returned by the query. This minimizes the number of queries and operations to perform in order to retrieve a set of results and their relationships.

func NewBatchingResultSet added in v0.12.0 

func NewBatchingResultSet(runner *batchQueryRunner) *BatchingResultSet

NewBatchingResultSet returns a new result set that performs batching underneath.

func (*BatchingResultSet) Close added in v0.12.0 

func (rs *BatchingResultSet) Close() error

Close will do nothing, as the internal result sets used by this are closed when the rows at fetched. It will never throw an error.

func (*BatchingResultSet) Get added in v0.12.0 

func (rs *BatchingResultSet) Get(_ Schema) (Record, error)

Get returns the next processed record and the last error occurred. Even though it accepts a schema, it is ignored, as the result set is already aware of it. This is here just to be able to imeplement the ResultSet interface.

func (*BatchingResultSet) Next added in v0.12.0 

func (rs *BatchingResultSet) Next() bool

Next advances the internal index of the fetched records in one. If there are no fetched records, will fetch the next batch. It will return false when there are no more rows.

func (*BatchingResultSet) RawScan added in v0.12.0 

func (rs *BatchingResultSet) RawScan(_ ...interface{}) error

RawScan will always throw an error, as this is not a supported operation of a batching result set.

type BeforeDeleter added in v0.13.0 

type BeforeDeleter interface {
	// BeforeDelete will do some operations before being deleted. If an error is
	// returned, it will prevent the delete from happening.
	BeforeDelete() error
}

BeforeDeleter will do some operations before being deleted.

type BeforeInserter added in v0.13.0 

type BeforeInserter interface {
	// BeforeInsert will do some operations before being inserted. If an error is
	// returned, it will prevent the insert from happening.
	BeforeInsert() error
}

BeforeInserter will do some operations before being inserted.

type BeforeSaver added in v0.13.0 

type BeforeSaver interface {
	// BeforeSave will do some operations before being updated or inserted. If an
	// error is returned, it will prevent the update or insert from happening.
	BeforeSave() error
}

BeforeSaver will do some operations before being updated or inserted.

type BeforeUpdater added in v0.13.0 

type BeforeUpdater interface {
	// BeforeUpdate will do some operations before being updated. If an error is
	// returned, it will prevent the update from happening.
	BeforeUpdate() error
}

BeforeUpdater will do some operations before being updated.

type ColumnAddresser 

type ColumnAddresser interface {
	// ColumnAddress returns the pointer to the column value of the given
	// column name, or an error if it does not exist in the model.
	ColumnAddress(string) (interface{}, error)
}

ColumnAddresser provides the pointer addresses of columns.

type ColumnOrder 

type ColumnOrder interface {
	// ToSql returns the SQL representation of the column with its order.
	ToSql(Schema) string
	// contains filtered or unexported methods
}

ColumnOrder represents a column name with its order.

func Asc 

func Asc(col SchemaField) ColumnOrder

Asc returns a column ordered by ascending order.

func Desc 

func Desc(col SchemaField) ColumnOrder

Desc returns a column ordered by descending order.

type Condition 

type Condition func(Schema) ToSqler

Condition represents a condition of filtering in a query.

func And 

func And(conds ...Condition) Condition

And returns the given conditions joined by logical ands.

func ArrayContainedBy added in v0.12.0 

func ArrayContainedBy(col SchemaField, values ...interface{}) Condition

ArrayContainedBy returns a condition that will be true when `col` has all its elements present in the given values.

func ArrayContains added in v0.12.0 

func ArrayContains(col SchemaField, values ...interface{}) Condition

ArrayContains returns a condition that will be true when `col` contains all the given values.

func ArrayEq added in v0.12.0 

func ArrayEq(col SchemaField, values ...interface{}) Condition

ArrayEq returns a condition that will be true when `col` is equal to an array with the given elements.

func ArrayGt added in v0.12.0 

func ArrayGt(col SchemaField, values ...interface{}) Condition

ArrayGt returns a condition that will be true when all elements in `col` are greater or equal than their counterparts in the given values, and one of the elements at least is greater than its counterpart in the given values. For example: for a col with values [1,2,3] and values [1,2,2], it will be true.

func ArrayGtOrEq added in v0.12.0 

func ArrayGtOrEq(col SchemaField, values ...interface{}) Condition

ArrayGtOrEq returns a condition that will be true when all elements in `col` are greater or equal than their counterparts in the given values. For example: for a col with values [1,2,2] and values [1,2,2], it will be true.

func ArrayLt added in v0.12.0 

func ArrayLt(col SchemaField, values ...interface{}) Condition

ArrayLt returns a condition that will be true when all elements in `col` are lower or equal than their counterparts in the given values, and one of the elements at least is lower than its counterpart in the given values. For example: for a col with values [1,2,2] and values [1,2,3], it will be true.

func ArrayLtOrEq added in v0.12.0 

func ArrayLtOrEq(col SchemaField, values ...interface{}) Condition

ArrayLtOrEq returns a condition that will be true when all elements in `col` are lower or equal than their counterparts in the given values. For example: for a col with values [1,2,2] and values [1,2,2], it will be true.

func ArrayNotEq added in v0.12.0 

func ArrayNotEq(col SchemaField, values ...interface{}) Condition

ArrayNotEq returns a condition that will be true when `col` is not equal to an array with the given elements.

func ArrayOverlap added in v0.12.0 

func ArrayOverlap(col SchemaField, values ...interface{}) Condition

ArrayOverlap returns a condition that will be true when `col` has elements in common with an array formed by the given values.

func Eq 

func Eq(col SchemaField, value interface{}) Condition

Eq returns a condition that will be true when `col` is equal to `value`.

func Gt 

func Gt(col SchemaField, value interface{}) Condition

Gt returns a condition that will be true when `col` is greater than `value`.

func GtOrEq 

func GtOrEq(col SchemaField, value interface{}) Condition

GtOrEq returns a condition that will be true when `col` is greater than `value` or equal.

func Ilike added in v1.1.4 

func Ilike(col SchemaField, value string) Condition

Ilike returns a condition that will be true when `col` matches the given `value`. The match is case-insensitive. See https://www.postgresql.org/docs/9.6/static/functions-matching.html.

func In 

func In(col SchemaField, values ...interface{}) Condition

In returns a condition that will be true when `col` is equal to any of the passed `values`.

func JSONContainedBy added in v0.13.0 

func JSONContainedBy(col SchemaField, elem interface{}) Condition

JSONContainedBy returns a condition that will be true when `col` is contained by the given element converted to JSON.

func JSONContains added in v0.13.0 

func JSONContains(col SchemaField, elem interface{}) Condition

JSONContains returns a condition that will be true when `col` contains the given element converted to JSON.

func JSONContainsAllKeys added in v0.13.0 

func JSONContainsAllKeys(col SchemaField, keys ...string) Condition

JSONContainsAllKeys returns a condition that will be true when `col` contains all the given keys. Will also match elements if the column is an array.

func JSONContainsAny added in v0.13.0 

func JSONContainsAny(col SchemaField, elems ...interface{}) Condition

JSONContainsAny returns a condition that will be true when `col` contains any of the given elements converted to json. Giving no elements will cause an error to be returned when the condition is evaluated.

func JSONContainsAnyKey added in v0.13.0 

func JSONContainsAnyKey(col SchemaField, keys ...string) Condition

JSONContainsAnyKey returns a condition that will be true when `col` contains any of the given keys. Will also match elements if the column is an array.

func JSONIsArray added in v0.13.0 

func JSONIsArray(col SchemaField) Condition

JSONIsArray returns a condition that will be true when `col` is a JSON array.

func JSONIsObject added in v0.13.0 

func JSONIsObject(col SchemaField) Condition

JSONIsObject returns a condition that will be true when `col` is a JSON object.

func Like added in v1.1.2 

func Like(col SchemaField, value string) Condition

Like returns a condition that will be true when `col` matches the given `value`. The match is case-sensitive. See https://www.postgresql.org/docs/9.6/static/functions-matching.html.

func Lt 

func Lt(col SchemaField, value interface{}) Condition

Lt returns a condition that will be true when `col` is lower than `value`.

func LtOrEq 

func LtOrEq(col SchemaField, value interface{}) Condition

LtOrEq returns a condition that will be true when `col` is lower than `value` or equal.

func MatchRegex added in v1.1.0 

func MatchRegex(col SchemaField, pattern string) Condition

MatchRegex returns a condition that will be true when `col` matches the given POSIX regex. Match is case insensitive.

func MatchRegexCase added in v1.1.0 

func MatchRegexCase(col SchemaField, pattern string) Condition

MatchRegexCase returns a condition that will be true when `col` matches the given POSIX regex. Match is case sensitive.

func Neq 

func Neq(col SchemaField, value interface{}) Condition

Neq returns a condition that will be true when `col` is not `value`.

func Not 

func Not(cond Condition) Condition

Not returns the given condition negated.

func NotIn 

func NotIn(col SchemaField, values ...interface{}) Condition

NotIn returns a condition that will be true when `col` is distinct to all of the passed `values`.

func NotMatchRegex added in v1.1.0 

func NotMatchRegex(col SchemaField, pattern string) Condition

NotMatchRegex returns a condition that will be true when `col` does not match the given POSIX regex. Match is case insensitive.

func NotMatchRegexCase added in v1.1.0 

func NotMatchRegexCase(col SchemaField, pattern string) Condition

NotMatchRegexCase returns a condition that will be true when `col` does not match the given POSIX regex. Match is case sensitive.

func NotSimilarTo added in v1.1.4 

func NotSimilarTo(col SchemaField, value string) Condition

NotSimilarTo returns a condition that will be true when `col` does not match the given `value`. See https://www.postgresql.org/docs/9.6/static/functions-matching.html.

func Or 

func Or(conds ...Condition) Condition

Or returns the given conditions joined by logical ors.

func SimilarTo added in v1.1.3 

func SimilarTo(col SchemaField, value string) Condition

SimilarTo returns a condition that will be true when `col` matches the given `value`. See https://www.postgresql.org/docs/9.6/static/functions-matching.html.

type ForeignKey added in v0.12.0 

type ForeignKey struct {
	*BaseSchemaField
	Inverse bool
}

ForeignKey contains the schema field of the foreign key and if it is an inverse foreign key or not.

func NewForeignKey added in v0.12.0 

func NewForeignKey(name string, inverse bool) *ForeignKey

NewForeignKey creates a new Foreign key with the given name.

type ForeignKeys 

type ForeignKeys map[string]*ForeignKey

ForeignKeys is a mapping between relationships and their foreign key field.

type GenericStorer added in v1.1.0 

type GenericStorer interface {
	// GenericStore returns the generic store in this type.
	GenericStore() *Store
	// SetGenericStore sets the generic store for this type.
	SetGenericStore(*Store)
}

GenericStorer is a type that contains a generic store and has methods to retrieve it and set it.

type Identifiable 

type Identifiable interface {
	// GetID returns the ID.
	GetID() Identifier
}

Identifiable must be implemented by those values that can be identified by an ID.

type Identifier added in v0.13.0 

type Identifier interface {
	sql.Scanner
	driver.Valuer
	// Equals reports whether the identifier and the given one are equal.
	Equals(Identifier) bool
	// IsEmpty returns whether the ID is empty or not.
	IsEmpty() bool
	// Raw returns the internal value of the identifier.
	Raw() interface{}
}

Identifier is a type used to identify a model.

type JSONKeyType added in v0.13.0 

type JSONKeyType string

JSONKeyType is the type of an object key in a JSON. 

const (
	// JSONAny represents a type that can't be casted.
	JSONAny JSONKeyType = ""
	// JSONText is a text json type.
	JSONText JSONKeyType = "text"
	// JSONInt is a numeric json type.
	JSONInt JSONKeyType = "bigint"
	// JSONFloat is a floating point json type.
	JSONFloat JSONKeyType = "decimal"
	// JSONBool is a boolean json type.
	JSONBool JSONKeyType = "bool"
)

type JSONSchemaArray added in v0.13.0 

type JSONSchemaArray struct {
	// contains filtered or unexported fields
}

JSONSchemaArray is a SchemaField that represents a JSON array.

func NewJSONSchemaArray added in v0.13.0 

func NewJSONSchemaArray(field string, paths ...string) *JSONSchemaArray

NewJSONSchemaArray creates a new SchemaField that is a json array.

func (*JSONSchemaArray) QualifiedName added in v0.13.0 

func (f *JSONSchemaArray) QualifiedName(schema Schema) string

func (*JSONSchemaArray) String added in v0.13.0 

func (f *JSONSchemaArray) String() string

type JSONSchemaKey added in v0.13.0 

type JSONSchemaKey struct {
	// contains filtered or unexported fields
}

JSONSchemaKey is a SchemaField that represents a key in a JSON object.

func NewJSONSchemaKey added in v0.13.0 

func NewJSONSchemaKey(typ JSONKeyType, field string, paths ...string) *JSONSchemaKey

NewJSONSchemaKey creates a new SchemaField that is a json key.

func (*JSONSchemaKey) QualifiedName added in v0.13.0 

func (f *JSONSchemaKey) QualifiedName(schema Schema) string

func (*JSONSchemaKey) String added in v0.13.0 

func (f *JSONSchemaKey) String() string

type LoggerFunc added in v1.1.4 

type LoggerFunc func(string, ...interface{})

LoggerFunc is a function that takes a log message with some arguments and logs it.

type Model 

type Model struct {
	// contains filtered or unexported fields
}

Model contains all the basic fields that make something a model, that is, the ID and some internal data used by kallax. To make a struct a model, it only needs to have Model embedded. 

type MyModel struct {
	kallax.Model
	Foo string
}

Custom name for the table can be specified using the struct tag `table` when embedding the Model. 

type MyModel struct {
	kallax.Model `table:"custom_name"`
}

Otherwise, the default name of the table is the name of the model converted to lower snake case. E.g: MyModel => my_model. No pluralization is done right now, but might be done in the future, so please, set the name of the tables yourself.

func NewModel 

func NewModel() Model

NewModel creates a new Model that is writable and not persisted.

func (*Model) AddVirtualColumn added in v0.12.0 

func (m *Model) AddVirtualColumn(name string, v Identifier)

AddVirtualColumn adds a new virtual column with the given name and value. This method is only intended for internal use. It is only exposed for technical reasons.

func (*Model) ClearVirtualColumns added in v0.12.0 

func (m *Model) ClearVirtualColumns()

ClearVirtualColumns clears all the previous virtual columns. This method is only intended for internal use. It is only exposed for technical reasons.

func (*Model) IsPersisted 

func (m *Model) IsPersisted() bool

IsPersisted returns whether the Model has already been persisted to the database or not.

func (*Model) IsWritable 

func (m *Model) IsWritable() bool

IsWritable returns whether this Model can be saved into the database. For example, a model with partially retrieved data is not writable, so it is not saved by accident and the data is corrupted. For example, if you select only 2 columns out of all the ones the table has, it will not be writable.

func (*Model) VirtualColumn added in v0.12.0 

func (m *Model) VirtualColumn(name string) Identifier

VirtualColumn returns the value of the virtual column with the given column name. This method is only intended for internal use. It is only exposed for technical reasons.

type NumericID added in v0.13.0 

type NumericID int64

NumericID is a wrapper for int64 that implements the Identifier interface. You don't need to actually use this as a type in your model. They will be automatically converted to and from in the generated code.

func (NumericID) Equals added in v0.13.0 

func (id NumericID) Equals(other Identifier) bool

Equals reports whether the ID and the given one are equals.

func (NumericID) IsEmpty added in v0.13.0 

func (id NumericID) IsEmpty() bool

IsEmpty returns whether the ID is empty or not. An empty ID means it has not been set yet.

func (NumericID) Raw added in v0.13.0 

func (id NumericID) Raw() interface{}

Raw returns the underlying raw value.

func (*NumericID) Scan added in v0.13.0 

func (id *NumericID) Scan(src interface{}) error

Scan implements the Scanner interface.

func (NumericID) String added in v0.13.0 

func (id NumericID) String() string

String returns the string representation of the ID.

func (NumericID) Value added in v0.13.0 

func (id NumericID) Value() (driver.Value, error)

Value implements the Valuer interface.

type Persistable 

type Persistable interface {
	// IsPersisted returns whether this Model is new in the store or not.
	IsPersisted() bool
	// contains filtered or unexported methods
}

Persistable must be implemented by those values that can be persisted.

type Query 

type Query interface {

	// Schema returns the schema of the query model.
	Schema() Schema
	// GetOffset returns the number of skipped rows in the query.
	GetOffset() uint64
	// GetLimit returns the max number of rows retrieved by the query.
	GetLimit() uint64
	// GetBatchSize returns the number of rows retrieved by the store per
	// batch. This is only used and has effect on queries with 1:N
	// relationships.
	GetBatchSize() uint64
	// contains filtered or unexported methods
}

Query is the common interface all queries must satisfy. The basic abilities of a query are compiling themselves to something executable and return some query settings.

type Record 

type Record interface {
	Identifiable
	Persistable
	Writable
	Relationable
	ColumnAddresser
	Valuer
	VirtualColumnContainer
}

Record is something that can be stored as a row in the database.

type RecordConstructor added in v0.12.0 

type RecordConstructor func() Record

RecordConstructor is a function that creates a record.

type RecordWithSchema added in v0.12.0 

type RecordWithSchema struct {
	Schema Schema
	Record Record
}

RecordWithSchema is a structure that contains both a record and its schema. Only for internal purposes.

type Relationable 

type Relationable interface {
	// NewRelationshipRecord returns a new Record for the relationship at the
	// given field.
	NewRelationshipRecord(string) (Record, error)
	// SetRelationship sets the relationship value at the given field.
	SetRelationship(string, interface{}) error
}

Relationable can perform operations related to relationships of a record.

type Relationship 

type Relationship struct {
	// Type is the kind of relationship this is.
	Type RelationshipType
	// Field is the field in the record where the relationship is.
	Field string
	// Schema is the schema of the relationship.
	Schema Schema
	// Filter establishes the filter to be applied when retrieving rows of the
	// relationships.
	Filter Condition
}

Relationship is a relationship with its schema and the field of te relation in the record.

type RelationshipType added in v0.12.0 

type RelationshipType byte

RelationshipType describes the type of the relationship. 

const (
	// OneToOne is a relationship between one record in a table and another in
	// another table.
	OneToOne RelationshipType = iota
	// OneToMany is a relationship between one record in a table and multiple
	// in another table.
	OneToMany
	// ManyToMany is a relationship between many records on both sides of the
	// relationship.
	// NOTE: It is not supported yet.
	ManyToMany
)

type ResultSet 

type ResultSet interface {
	// RawScan allows for raw scanning of fields in a result set.
	RawScan(...interface{}) error
	// Next moves the pointer to the next item in the result set and returns
	// if there was any.
	Next() bool
	// Get returns the next record of the given schema.
	Get(Schema) (Record, error)
	io.Closer
}

ResultSet is the common interface all result sets need to implement.

type ScalarCond added in v1.0.0 

type ScalarCond func(col SchemaField, value interface{}) Condition

ScalarCond returns a kallax.Condition that compares a property with the passed values, considering its scalar values (eq, gt, gte, lt, lte, neq)

type Schema 

type Schema interface {
	// Alias returns the name of the alias used in queries for this schema.
	Alias() string
	// Table returns the table name.
	Table() string
	// ID returns the name of the identifier of the table.
	ID() SchemaField
	// Columns returns the list of columns in the schema.
	Columns() []SchemaField
	// ForeignKey returns the name of the foreign key of the given model field.
	ForeignKey(string) (*ForeignKey, bool)
	// WithAlias returns a new schema with the given string added to the
	// default alias.
	// Calling WithAlias on a schema returned by WithAlias not return a
	// schema based on the child, but another based on the parent.
	WithAlias(string) Schema
	// New creates a new record with the given schema.
	New() Record
	// contains filtered or unexported methods
}

Schema represents a table schema in the database. Contains some information like the table name, its columns, its identifier and so on.

type SchemaField 

type SchemaField interface {

	// String returns the string representation of the field. That is, its name.
	String() string
	// QualifiedString returns the name of the field qualified by the alias of
	// the given schema.
	QualifiedName(Schema) string
	// contains filtered or unexported methods
}

SchemaField is a named field in the table schema.

func AtJSONPath added in v0.13.0 

func AtJSONPath(field SchemaField, typ JSONKeyType, path ...string) SchemaField

AtJSONPath returns the schema field to query an arbitrary JSON element at the given path.

func NewSchemaField 

func NewSchemaField(name string) SchemaField

NewSchemaField creates a new schema field with the given name.

type Store 

type Store struct {
	// contains filtered or unexported fields
}

Store is a structure capable of retrieving records from a concrete table in the database.

func NewStore 

func NewStore(db *sql.DB) *Store

NewStore returns a new Store instance.

func (*Store) Count 

func (s *Store) Count(q Query) (count int64, err error)

Count returns the number of rows selected by the given query.

func (*Store) Debug added in v1.1.4 

func (s *Store) Debug() *Store

Debug returns a new store that will print all SQL statements to stdout using the log.Printf function.

func (*Store) DebugWith added in v1.1.4 

func (s *Store) DebugWith(logger LoggerFunc) *Store

DebugWith returns a new store that will print all SQL statements using the given logger function.

func (*Store) Delete 

func (s *Store) Delete(schema Schema, record Record) error

Delete removes the record from the table. A non-new record with non-empty ID is required.

func (*Store) Find 

func (s *Store) Find(q Query) (ResultSet, error)

Find performs a query and returns a result set with the results.

func (*Store) Insert 

func (s *Store) Insert(schema Schema, record Record) error

Insert insert the given record in the table, returns error if no-new record is given. The record id is set if it's empty.

func (*Store) MustCount 

func (s *Store) MustCount(q Query) int64

MustCount returns the number of rows selected by the given query. It panics if the query fails.

func (*Store) MustFind 

func (s *Store) MustFind(q Query) ResultSet

MustFind performs a query and returns a result set with the results. It panics if the query fails.

func (*Store) RawExec 

func (s *Store) RawExec(sql string, params ...interface{}) (int64, error)

RawExec executes a raw SQL query with the given parameters and returns the number of affected rows.

func (*Store) RawQuery 

func (s *Store) RawQuery(sql string, params ...interface{}) (ResultSet, error)

RawQuery performs a raw SQL query with the given parameters and returns a result set with the results. WARNING: A result set created from a raw query can only be scanned using the RawScan method of ResultSet, instead of Scan.

func (*Store) Reload 

func (s *Store) Reload(schema Schema, record Record) error

Reload refreshes the record with the data in the database and makes the record writable.

func (*Store) Save 

func (s *Store) Save(schema Schema, record Record) (updated bool, err error)

Save inserts or updates the given record in the table.

func (*Store) Transaction 

func (s *Store) Transaction(callback func(*Store) error) error

Transaction executes the given callback in a transaction and rollbacks if an error is returned. The transaction is only open in the store passed as a parameter to the callback. If a transaction is already opened in this store, instead of opening a new one, the other will be reused.

func (*Store) Update 

func (s *Store) Update(schema Schema, record Record, cols ...SchemaField) (int64, error)

Update updates the given fields of a record in the table. All fields are updated if no fields are provided. For an update to take place, the record is required to have a non-empty ID and not to be a new record. Returns the number of updated rows and an error, if any.

type Timestamps 

type Timestamps struct {
	// CreatedAt is the time where the object was created.
	CreatedAt time.Time
	// UpdatedAt is the time where the object was updated.
	UpdatedAt time.Time
}

Timestamps contains the dates of the last time the model was created or deleted. Because this is such a common functionality in models, it is provided by default by the library. It is intended to be embedded in the model. 

type MyModel struct {
	kallax.Model
	kallax.Timestamps
	Foo string
}

func (*Timestamps) BeforeSave added in v0.12.0 

func (t *Timestamps) BeforeSave() error

BeforeSave updates the last time the model was updated every single time the model is saved, and the last time the model was created only if the model has no date of creation yet.

type ToSqler added in v1.2.0 

type ToSqler interface {
	squirrel.Sqlizer
}

ToSqler is the interface that wraps the ToSql method. It's a wrapper around squirrel.Sqlizer to avoid having to import that as well when using kallax.

type ULID added in v0.13.0 

type ULID uuid.UUID

ULID is an ID type provided by kallax that is a lexically sortable UUID. The internal representation is an ULID (https://github.com/oklog/ulid). It already implements sql.Scanner and driver.Valuer, so it's perfectly safe for database usage.

func NewULID added in v0.13.0 

func NewULID() ULID

NewULID returns a new ULID, which is a lexically sortable UUID.

func NewULIDFromText added in v1.0.4 

func NewULIDFromText(text string) (ULID, error)

NewULIDFromText creates a new ULID from its string representation. Will return an error if the text is not a valid ULID.

func (ULID) Equals added in v0.13.0 

func (id ULID) Equals(other Identifier) bool

Equals reports whether the ID and the given one are equals.

func (ULID) IsEmpty added in v0.13.0 

func (id ULID) IsEmpty() bool

IsEmpty returns whether the ID is empty or not. An empty ID means it has not been set yet.

func (ULID) MarshalText added in v1.0.3 

func (id ULID) MarshalText() ([]byte, error)

func (ULID) Raw added in v0.13.0 

func (id ULID) Raw() interface{}

Raw returns the underlying raw value.

func (*ULID) Scan added in v0.13.0 

func (id *ULID) Scan(src interface{}) error

Scan implements the Scanner interface.

func (ULID) String added in v0.13.0 

func (id ULID) String() string

String returns the string representation of the ID.

func (*ULID) UnmarshalText added in v1.0.2 

func (u *ULID) UnmarshalText(text []byte) (err error)

UnmarshalText implements the encoding.TextUnmarshaler interface. Following formats are supported: "6ba7b810-9dad-11d1-80b4-00c04fd430c8", "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}", "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8" Implements the exact same code as the UUID UnmarshalText removing the version check.

func (ULID) Value added in v0.13.0 

func (id ULID) Value() (driver.Value, error)

Value implements the Valuer interface.

type UUID added in v0.13.0 

type UUID uuid.UUID

UUID is a wrapper type for uuid.UUID that implements the Identifier interface. You don't need to actually use this as a type in your model. They will be automatically converted to and from in the generated code.

func (UUID) Equals added in v0.13.0 

func (id UUID) Equals(other Identifier) bool

Equals reports whether the ID and the given one are equals.

func (UUID) IsEmpty added in v0.13.0 

func (id UUID) IsEmpty() bool

IsEmpty returns whether the ID is empty or not. An empty ID means it has not been set yet.

func (UUID) Raw added in v0.13.0 

func (id UUID) Raw() interface{}

Raw returns the underlying raw value.

func (*UUID) Scan added in v0.13.0 

func (id *UUID) Scan(src interface{}) error

Scan implements the Scanner interface.

func (UUID) String added in v0.13.0 

func (id UUID) String() string

String returns the string representation of the ID.

func (UUID) Value added in v0.13.0 

func (id UUID) Value() (driver.Value, error)

Value implements the Valuer interface.

type Valuer 

type Valuer interface {
	// Value returns the value of the given column, or an error if it does not
	// exist in the model.
	Value(string) (interface{}, error)
}

Valuer provides the values for columns.

type VirtualColumnContainer added in v0.12.0 

type VirtualColumnContainer interface {
	// ClearVirtualColumns removes all virtual columns.
	ClearVirtualColumns()
	// AddVirtualColumn adds a new virtual column with the given name and value
	AddVirtualColumn(string, Identifier)
	// VirtualColumn returns the virtual column with the given column name.
	VirtualColumn(string) Identifier
}

VirtualColumnContainer contains a collection of virtual columns and manages them.

type Writable 

type Writable interface {
	// IsWritable returns whether this Model can be saved into the database.
	IsWritable() bool
	// contains filtered or unexported methods
}

Writable must be implemented by those values that defines internally if they can be sent back to the database to be stored with its changes.

Source Files

View all Source files

Directories

Path Synopsis
IMPORTANT! This is auto generated code by https://github.com/src-d/go-kallax Please, do not touch the code below, and if you do, do it under your own risk.
 IMPORTANT! This is auto generated code by https://github.com/src-d/go-kallax Please, do not touch the code below, and if you do, do it under your own risk.
Package generator implements the processor of source code and generator of kallax models based on Go source code.
 Package generator implements the processor of source code and generator of kallax models based on Go source code.
cli/kallax
cli/kallax/cmd
IMPORTANT! This is auto generated code by https://github.com/src-d/go-kallax Please, do not touch the code below, and if you do, do it under your own risk.
 IMPORTANT! This is auto generated code by https://github.com/src-d/go-kallax Please, do not touch the code below, and if you do, do it under your own risk.
fixtures
Package types provides implementation of some wrapper SQL types.
 Package types provides implementation of some wrapper SQL types.

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