machgo

package module
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 Go to latest Published: Mar 20, 2019 License: GPL-3.0 Imports: 13 Imported by: 0

README

machgo

Build Status Coverage Status GoDoc

machgo is a ORM-ish database library for go.

Because I am chronically lazy, this readme is a WIP.

Check out the godocs!

Example Usage

Simple usage

Let's say you have the following table:

CREATE TABLE images (
  id bigint PRIMARY KEY,
  post_id bigint NOT NULL,
  filename text,
  mime_type text,
  created date DEFAULT now(),
  updated date DEFAULT now()
);

Then you might create the following object representation:

import (
    "github.com/daihasso/machgo/database"
)

type Image struct {
  PostID int64 `db:"post_id"`

  MimeType string `db:"mime_type"`
  OriginalFileName string `db:"file_name"`
}

Next you might want to create a database connection:

import (
    "sync"

    "github.com/daihasso/machgo/pool"
    "github.com/daihasso/machgo/pool/config"
)

var MyDBConn *pool.ConnectionPool

func init() {
    once.Do(func() {
        MyDBConn, err := config.PostgresPool(
            config.Username("mypostgresuser"),
            config.Password("mysecretpassword"),
            config.Host("localhost"),
            config.Port(5432),
            config.DatabaseName("mycooldatabase"),
        )
        if err != nil {
            panic(err)
        }

        // This lets us share a connection across further machgo calls.
        SetGlobalConnectionPool(MyDBConn)
    })
}

And to retrieve single image you might do:


import(
    "github.com/daihasso/machgo/pool/ses"
)

func getImage(id int64) *Image {
    session, err := sess.NewSession()
    if err != nil {
        panic(err)
    }
    result := &Image{}
    err := session.GetObject(result, id)
    if err != nil {
        panic(err)
    }

    return result
}
More advanced usage

Let's say you want many images per post so you expand the previous table by using a lookup table:

CREATE TABLE images (
  id bigint PRIMARY KEY,
  filename text,
  mime_type text,
  created date DEFAULT now(),
  updated date DEFAULT now()
);

CREATE TABLE post_images (
  post_id bigint NOT NULL,
  image_id bigint REFERENCES images (id) ON DELETE CASCADE,
  created timestamp with time zone DEFAULT now(),
  updated timestamp with time zone DEFAULT now(),
  PRIMARY KEY(post_id, image_id)
);

Then you might create the following object representation:

// post_image.go
type PostImage struct {
    machgo.DefaultCompositeDBObject

    ID int64 `db:"post_id"`
    ImageID int64 `db:"image_id"`
}

func (self *PostImage) GetTableName() string {
    return "post_images"
}

// GetColumnNames is required for composite objects to define what columns
// matter.
func (s *PostImage) GetColumnNames() []string {
    return []string{"post_id", "image_id"}
}

// image_object.go
type Image struct {
    database.DefaultDBObject

    // Defining the db value as 'foreign' here lets the machgo know that it
    // needs to pull the column from the table specified in the dbforeign tag
    // value.
    PostID int64 `db:"post_id,foreign" dbforeign:"post_images"`

    MimeType string `db:"mime_type"`
    OriginalFileName string `db:"file_name"`
}

func (self *Image) GetTableName() string {
    return "images"
}

// This function defines what relationships with other tables or objects
func (self *Image) Relationships() []machgo.Relationship {
    return []machgo.Relationship{
        machgo.Relationship{
            SelfObject: self,
            SelfColumn:   "id",
            TargetObject: &ImagePost{},
            TargetColumn: "image_id",
        },
    }
}

All the same actions as above will still work the same but in order to get images for a post (or set of posts).

import (
  "github.com/daihasso/machgo/pool/session"
  . "github.com/daihasso/machgo/dsl/dot"
)

func findImagesForPost(postIDs []string) {
    image := &Image{}
    postImage := &PostImage{}

    session, err := sess.NewSession()
    if err != nil {
        panic(err)
    }
    qs := session.Query(postImage, image).SelectObject(image).Where(
        Eq(ObjectColumn(postImage, "image_id"), ObjectColumn(image, "id")),
        In(ObjectColumn(postImage, "post_id"), Const(postIDs...)),
    )

    results, err := qs.Results()
    if err != nil {
        panic(err)
    }

    images := make([]*Image, 0)
    err = results.WriteAllTo(&images)
    if err != nil {
      panic(err)
    }

    return images
}

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func SnakeToUpperCamel 

func SnakeToUpperCamel(raw string) string

SnakeToUpperCamel converts a string in snake_case to a string in UpperCamelCase.

Types

type AliasObjValMap 

type AliasObjValMap map[string]*reflect.Value

type AliasedObjects 

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

func NewAliasedObjects 

func NewAliasedObjects(objects ...Object) (*AliasedObjects, error)

func NewAliasedObjectsFromExisting 

func NewAliasedObjectsFromExisting(
	aliasedObjectMap map[string]Object,
) (*AliasedObjects, error)

NewAliasedObjectsFromExisting takes an oldfashion map-style aliased object and creates a new AliasedObjects struct.

func (AliasedObjects) ObjectAlias 

func (self AliasedObjects) ObjectAlias(
	object Object,
) (string, error)

func (AliasedObjects) ObjectIsAliased 

func (self AliasedObjects) ObjectIsAliased(object Object) bool

func (AliasedObjects) TableForAlias 

func (self AliasedObjects) TableForAlias(alias string) string

func (AliasedObjects) TypeForAlias 

func (self AliasedObjects) TypeForAlias(alias string) *reflect.Type

type ColumnAlias 

type ColumnAlias struct {
	TableAlias,
	ColumnName string
}

func ColumnAliasFromString 

func ColumnAliasFromString(rawColumn string) (*ColumnAlias, bool)

func (ColumnAlias) String 

func (self ColumnAlias) String() string

type ColumnAliasField 

type ColumnAliasField struct {
	ColumnAlias
	FieldName string
}

type CompositeKey 

type CompositeKey interface {
	GetColumnNames() []string
	SetColumnNames([]string)
}

CompositeKey is a composite key made up of one or more columns.

type CompositeObject 

type CompositeObject interface {
	Object
	CompositeKey
}

CompositeObject is an object which has an CompositeAttribute.

type DefaultAttributes 

type DefaultAttributes interface {
	Update()
	Init()
}

DefaultAttributes are a set of default attributes for an object.

type DefaultCompositeDBObject 

type DefaultCompositeDBObject struct {
	JSONExportedDefaultAttributes
	DefaultDiffable
	// contains filtered or unexported fields
}

DefaultCompositeDBObject is a basic object with standard implementations.

func (*DefaultCompositeDBObject) GetColumnNames 

func (bo *DefaultCompositeDBObject) GetColumnNames() []string

GetColumnNames retrieves the database column names for the composite key.

func (DefaultCompositeDBObject) IsSaved 

func (bo DefaultCompositeDBObject) IsSaved() bool

IsSaved will return a bool encapsulating wether the object has been saved or not.

func (*DefaultCompositeDBObject) PostInsertActions 

func (bo *DefaultCompositeDBObject) PostInsertActions() (err error)

PostInsertActions is a NOOP for default UUID object.

func (*DefaultCompositeDBObject) PreInsertActions 

func (bo *DefaultCompositeDBObject) PreInsertActions() (err error)

PreInsertActions will initialize the default attributes.

func (*DefaultCompositeDBObject) SetColumnNames 

func (bo *DefaultCompositeDBObject) SetColumnNames(columns []string)

SetColumnNames retrieves the database column names for the composite key.

func (*DefaultCompositeDBObject) SetSaved 

func (bo *DefaultCompositeDBObject) SetSaved(saved bool)

SetSaved modifies the saved status of the object.

type DefaultDBObject 

type DefaultDBObject struct {
	JSONExportedDefaultAttributes
	DefaultDiffable
	ID *IntID `json:"id" db:"id"`
	// contains filtered or unexported fields
}

DefaultDBObject is a basic object with standard implementations.

func (DefaultDBObject) GetID 

func (bo DefaultDBObject) GetID() ID

GetID retrieves the ID.

func (DefaultDBObject) GetIDColumn 

func (bo DefaultDBObject) GetIDColumn() string

GetIDColumn returns the column the ID lives in.

func (DefaultDBObject) IDIsSet 

func (bo DefaultDBObject) IDIsSet() bool

IDIsSet will check if the ID is set and return true if it has been set.

func (*DefaultDBObject) IsSaved 

func (bo *DefaultDBObject) IsSaved() bool

IsSaved will return a bool encapsulating wether the object has been saved or not.

func (*DefaultDBObject) NewID 

func (bo *DefaultDBObject) NewID() ID

NewID returns nil because it can't generate a new ID without seeing existing IDs.

func (*DefaultDBObject) PostInsertActions 

func (bo *DefaultDBObject) PostInsertActions() (err error)

PostInsertActions is a NOOP for default UUID object.

func (*DefaultDBObject) PreInsertActions 

func (bo *DefaultDBObject) PreInsertActions() (err error)

PreInsertActions will initialize the default attributes.

func (*DefaultDBObject) SetID 

func (bo *DefaultDBObject) SetID(id ID) error

SetID sets the ID.

func (*DefaultDBObject) SetSaved 

func (bo *DefaultDBObject) SetSaved(saved bool)

SetSaved sets the saved status for the object.

type DefaultDiffable 

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

DefaultDiffable is the basic standard implementation of a diffable.

func (DefaultDiffable) GetLastSavedValue 

func (dd DefaultDiffable) GetLastSavedValue(name string) interface{}

GetLastSavedValue will get a given value from the last values map.

func (*DefaultDiffable) SetLastSavedValue 

func (dd *DefaultDiffable) SetLastSavedValue(name string, val interface{})

SetLastSavedValue will set a given value in the last values map.

type Diffable 

type Diffable interface {
	GetLastSavedValue(string) interface{}
	SetLastSavedValue(string, interface{})
}

Diffable allows something to track changes to the item before saving to optimize inserts.

type ID 

type ID interface {
	sql.Scanner
	driver.Valuer
	fmt.Stringer
	json.Marshaler
	json.Unmarshaler
}

ID is a type of attribute for an object that implements some conversion methods. Required conversions:

  • From/To database
  • To string
  • From/To JSON

type IDAttribute 

type IDAttribute interface {
	SetID(ID) error
	GetID() ID
	IDIsSet() bool
	NewID() ID
	GetIDColumn() string
}

IDAttribute is an interface for doing common ID operations.

type IDObject 

type IDObject interface {
	Object
	IDAttribute
}

IDObject is an object which has an IDAttribute.

type IntID 

type IntID struct {
	ID int64
}

IntID is an object with an integer ID.

func (IntID) MarshalJSON 

func (ii IntID) MarshalJSON() ([]byte, error)

MarshalJSON returns the JSON representation.

func (*IntID) Scan 

func (ii *IntID) Scan(src interface{}) error

Scan reads data from the database into an IntID.

func (IntID) String 

func (ii IntID) String() string

String returns the string representation.

func (IntID) UnmarshalJSON 

func (ii IntID) UnmarshalJSON(source []byte) error

UnmarshalJSON returns the JSON representation.

func (IntID) Value 

func (ii IntID) Value() (driver.Value, error)

Value returns the database value for the IntID.

type JSONExportedDefaultAttributes 

type JSONExportedDefaultAttributes struct {
	Created types.Timestamp `db:"created" json:"created,omitempty"`
	Updated types.Timestamp `db:"updated" json:"updated,omitempty"`
}

JSONExportedDefaultAttributes is a set of sensible default attributes that are serialized into json.

func (*JSONExportedDefaultAttributes) Init 

func (j *JSONExportedDefaultAttributes) Init()

Init will initialize the created & updated time.

func (*JSONExportedDefaultAttributes) Update 

func (j *JSONExportedDefaultAttributes) Update()

Update will initialize the updated time.

type Object 

type Object interface {
	GetTableName() string
	IsSaved() bool
	SetSaved(bool)

	PreInsertActions() error
	PostInsertActions() error
}

Object is a database object able to be written to the DB.

type QueryResult 

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

QueryResult is a set of all the results from a query in objects.

func NewQueryResult 

func NewQueryResult(
	rows *sqlx.Rows,
	aliasedObjects *AliasedObjects,
	columnAliasFields []ColumnAliasField,
) (*QueryResult, error)

func (QueryResult) WriteTo 

func (self QueryResult) WriteTo(objects ...interface{}) error

type QueryResults 

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

func NewQueryResults 

func NewQueryResults(
	tx *sqlx.Tx,
	rows *sqlx.Rows,
	aliasedObjects *AliasedObjects,
	typeBSFieldMap map[reflect.Type]*refl.GroupedFieldsWithBS,
) *QueryResults

func (*QueryResults) Err 

func (self *QueryResults) Err() error

func (*QueryResults) GetResult 

func (self *QueryResults) GetResult() *QueryResult

func (*QueryResults) Next 

func (self *QueryResults) Next() bool

func (*QueryResults) WriteAllTo 

func (self *QueryResults) WriteAllTo(
	objectSlices ...interface{},
) (retErr error)

type Relationship 

type Relationship struct {
	SelfObject,
	TargetObject Object
	SelfColumn,
	TargetColumn string
}

Relationship is a representation of how two objects join together.

func (Relationship) Invert 

func (self Relationship) Invert() *Relationship

Invert takes the relationship and swaps the self with the target. This essentially has the effect of changing: 

foo.bar=baz.fizz

Into: 

baz.fizz=foo.bar

func (Relationship) SelfTable 

func (self Relationship) SelfTable() string

func (Relationship) TargetTable 

func (self Relationship) TargetTable() string

type Relationshipable 

type Relationshipable interface {
	Relationships() []Relationship
}

Relationshipable is a type that has at least on relationship.

type SimpleCompositeKey 

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

SimpleCompositeKey is a simple composite key implementation.

func (SimpleCompositeKey) GetColumnNames 

func (sck SimpleCompositeKey) GetColumnNames() []string

GetColumnNames retrieves the database column names for the composite key.

func (*SimpleCompositeKey) SetColumnNames 

func (sck *SimpleCompositeKey) SetColumnNames(columns []string)

SetColumnNames retrieves the database column names for the composite key.

type UnexportedDefaultAttributes 

type UnexportedDefaultAttributes struct {
	Created types.Timestamp `db:"created" json:"-"`
	Updated types.Timestamp `db:"updated" json:"-"`
}

UnexportedDefaultAttributes is a set of sensible default attributes for an object that are not exported when serialized.

func (*UnexportedDefaultAttributes) Init 

func (j *UnexportedDefaultAttributes) Init()

Init will initialize the created time and updated time.

func (*UnexportedDefaultAttributes) Update 

func (j *UnexportedDefaultAttributes) Update()

Update will update the updated time.

Source Files

View all Source files

Directories

Path Synopsis
dbtype
dsl
dot
Package dot contains mostly a set of shims for dot importing machgo DSL.
 Package dot contains mostly a set of shims for dot importing machgo DSL.
config
sess

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