gorm

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 Go to latest Published: Feb 17, 2023 License: Apache-2.0 Imports: 16 Imported by: 0

README

GORM

The fantastic ORM library for Golang, aims to be developer friendly.

Overview

  • Chainable API
  • Embedded Structs
  • Relations
  • Callbacks (before/after create/save/update/delete/find)
  • Soft Deletes
  • Auto Migrations
  • Transactions
  • Customizable Logger
  • Iteration Support via Rows
  • Scopes
  • sql.Scanner support
  • Every feature comes with tests
  • Convention Over Configuration
  • Developer Friendly

Conventions

// E.g finding an existing User
var user User
// Gorm will know to use table "users" ("user" if pluralisation has been disabled) for all operations.
db.First(&user)

// creating a new User
DB.Save(&User{Name: "xxx"}) // table "users"
  • Column name is the snake case of field's name
  • Use Id field as primary key
  • Use tag sql to change field's property, change the tag name with db.SetTagIdentifier(new_name)
  • Use CreatedAt to store record's created time if field exists
  • Use UpdatedAt to store record's updated time if field exists
  • Use DeletedAt to store record's deleted time if field exists Soft Delete

Getting Started

Install

go get -u github.com/jinzhu/gorm

Define Models (Structs)

type User struct {
    Id           int64
    Birthday     time.Time
    Age          int64
    Name         string  `sql:"size:255"`
    CreatedAt    time.Time
    UpdatedAt    time.Time
    DeletedAt    time.Time

    Emails            []Email         // One-To-Many relationship (has many)
    BillingAddress    Address         // One-To-One relationship (has one)
    BillingAddressId  sql.NullInt64   // Foreign key of BillingAddress
    ShippingAddress   Address         // One-To-One relationship (has one)
    ShippingAddressId int64           // Foreign key of ShippingAddress
    IgnoreMe          int64 `sql:"-"` // Ignore this field
    Languages         []Language `gorm:"many2many:user_languages;"` // Many-To-Many relationship, 'user_languages' is join table
}

type Email struct {
    Id         int64
    UserId     int64   // Foreign key for User (belongs to)
    Email      string  `sql:"type:varchar(100);"` // Set field's type
    Subscribed bool
}

type Address struct {
    Id       int64
    Address1 string         `sql:"not null;unique"` // Set field as not nullable and unique
    Address2 string         `sql:"type:varchar(100);unique"`
    Post     sql.NullString `sql:not null`
}

type Language struct {
    Id   int64
    Name string
}

Initialize Database


import (
    "github.com/jinzhu/gorm"
    _ "github.com/lib/pq"
    _ "github.com/go-sql-driver/mysql"
    _ "github.com/mattn/go-sqlite3"
)

db, err := gorm.Open("postgres", "user=gorm dbname=gorm sslmode=disable")
// db, err := gorm.Open("mysql", "gorm:gorm@/gorm?charset=utf8&parseTime=True")
// db, err := gorm.Open("sqlite3", "/tmp/gorm.db")

// Get database connection handle [*sql.DB](http://golang.org/pkg/database/sql/#DB)
db.DB()

// Then you could invoke `*sql.DB`'s functions with it
db.DB().Ping()
db.DB().SetMaxIdleConns(10)
db.DB().SetMaxOpenConns(100)

// Disable table name's pluralization
db.SingularTable(true)

Migration

// Create table
db.CreateTable(User{})

// Drop table
db.DropTable(User{})

// Drop table if exists
db.DropTableIfExists(User{})

// Automating Migration
db.AutoMigrate(User{})
db.AutoMigrate(User{}, Product{}, Order{})

// Feel free to change your struct, AutoMigrate will keep your database up-to-date.
// Fyi, AutoMigrate will only *add new columns*, it won't update column's type or delete unused columns, to make sure your data is safe.
// If the table is not existing, AutoMigrate will create the table automatically.

// Add index
db.Model(User{}).AddIndex("idx_user_name", "name")

// Multiple column index
db.Model(User{}).AddIndex("idx_user_name_age", "name", "age")

// Add unique index
db.Model(User{}).AddUniqueIndex("idx_user_name", "name")

// Multiple column unique index
db.Model(User{}).AddUniqueIndex("idx_user_name_age", "name", "age")

// Remove index
db.Model(User{}).RemoveIndex("idx_user_name")

Basic CRUD

Create Record

user := User{Name: "Jinzhu", Age: 18, Birthday: time.Now()}

// returns true if record hasn’t been saved (primary key `Id` is blank)
db.NewRecord(user) // => true

db.Create(&user)

// will ruturn false after `user` created
db.NewRecord(user) // => false

// You could use `Save` to create record also if its primary key is null
db.Save(&user)

// Associations will be saved automatically when insert the record
user := User{
        Name:            "jinzhu",
        BillingAddress:  Address{Address1: "Billing Address - Address 1"},
        ShippingAddress: Address{Address1: "Shipping Address - Address 1"},
        Emails:          []Email{{Email: "jinzhu@example.com"}, {Email: "jinzhu-2@example@example.com"}},
        Languages:       []Language{{Name: "ZH"}, {Name: "EN"}},
}

db.Create(&user)
//// BEGIN TRANSACTION;
//// INSERT INTO "addresses" (address1) VALUES ("Billing Address - Address 1");
//// INSERT INTO "addresses" (address1) VALUES ("Shipping Address - Address 1");
//// INSERT INTO "users" (name,billing_address_id,shipping_address_id) VALUES ("jinzhu", 1, 2);
//// INSERT INTO "emails" (user_id,email) VALUES (111, "jinzhu@example.com");
//// INSERT INTO "emails" (user_id,email) VALUES (111, "jinzhu-2@example.com");
//// INSERT INTO "languages" ("name") VALUES ('ZH');
//// INSERT INTO user_languages ("user_id","language_id") VALUES (111, 1);
//// INSERT INTO "languages" ("name") VALUES ('EN');
//// INSERT INTO user_languages ("user_id","language_id") VALUES (111, 2);
//// COMMIT;

Refer Associations for how to works with associations

Query

// Get the first record
db.First(&user)
//// SELECT * FROM users ORDER BY id LIMIT 1;

// Get the last record
db.Last(&user)
//// SELECT * FROM users ORDER BY id DESC LIMIT 1;

// Get all records
db.Find(&users)
//// SELECT * FROM users;

// Get record with primary key
db.First(&user, 10)
//// SELECT * FROM users WHERE id = 10;
Query With Where (Plain SQL)
// Get the first matched record
db.Where("name = ?", "jinzhu").First(&user)
//// SELECT * FROM users WHERE name = 'jinzhu' limit 1;

// Get all matched records
db.Where("name = ?", "jinzhu").Find(&users)
//// SELECT * FROM users WHERE name = 'jinzhu';

db.Where("name <> ?", "jinzhu").Find(&users)

// IN
db.Where("name in (?)", []string{"jinzhu", "jinzhu 2"}).Find(&users)

// LIKE
db.Where("name LIKE ?", "%jin%").Find(&users)

// AND
db.Where("name = ? and age >= ?", "jinzhu", "22").Find(&users)
Query With Where (Struct & Map)
// Struct
db.Where(&User{Name: "jinzhu", Age: 20}).First(&user)
//// SELECT * FROM users WHERE name = "jinzhu" AND age = 20 LIMIT 1;

// Map
db.Where(map[string]interface{}{"name": "jinzhu", "age": 20}).Find(&users)
//// SELECT * FROM users WHERE name = "jinzhu" AND age = 20;

// Slice of primary keys
db.Where([]int64{20, 21, 22}).Find(&users)
//// SELECT * FROM users WHERE id IN (20, 21, 22);
Query With Not
db.Not("name", "jinzhu").First(&user)
//// SELECT * FROM users WHERE name <> "jinzhu" LIMIT 1;

// Not In
db.Not("name", []string{"jinzhu", "jinzhu 2"}).Find(&users)
//// SELECT * FROM users WHERE name NOT IN ("jinzhu", "jinzhu 2");

// Not In slice of primary keys
db.Not([]int64{1,2,3}).First(&user)
//// SELECT * FROM users WHERE id NOT IN (1,2,3);

db.Not([]int64{}).First(&user)
//// SELECT * FROM users;

// Plain SQL
db.Not("name = ?", "jinzhu").First(&user)
//// SELECT * FROM users WHERE NOT(name = "jinzhu");

// Struct
db.Not(User{Name: "jinzhu"}).First(&user)
//// SELECT * FROM users WHERE name <> "jinzhu";
Query With Inline Condition
// Get by primary key
db.First(&user, 23)
//// SELECT * FROM users WHERE id = 23 LIMIT 1;

// Plain SQL
db.Find(&user, "name = ?", "jinzhu")
//// SELECT * FROM users WHERE name = "jinzhu";

db.Find(&users, "name <> ? AND age > ?", "jinzhu", 20)
//// SELECT * FROM users WHERE name <> "jinzhu" AND age > 20;

// Struct
db.Find(&users, User{Age: 20})
//// SELECT * FROM users WHERE age = 20;

// Map
db.Find(&users, map[string]interface{}{"age": 20})
//// SELECT * FROM users WHERE age = 20;
Query With Or
db.Where("role = ?", "admin").Or("role = ?", "super_admin").Find(&users)
//// SELECT * FROM users WHERE role = 'admin' OR role = 'super_admin';

// Struct
db.Where("name = 'jinzhu'").Or(User{Name: "jinzhu 2"}).Find(&users)
//// SELECT * FROM users WHERE name = 'jinzhu' OR name = 'jinzhu 2';

// Map
db.Where("name = 'jinzhu'").Or(map[string]interface{}{"name": "jinzhu 2"}).Find(&users)
Query Chains

Gorm has a chainable API, you could use it like this

db.Where("name <> ?","jinzhu").Where("age >= ? and role <> ?",20,"admin").Find(&users)
//// SELECT * FROM users WHERE name <> 'jinzhu' AND age >= 20 AND role <> 'admin';

db.Where("role = ?", "admin").Or("role = ?", "super_admin").Not("name = ?", "jinzhu").Find(&users)

Update

// Update an existing struct
db.First(&user)
user.Name = "jinzhu 2"
user.Age = 100
db.Save(&user)
//// UPDATE users SET name='jinzhu 2', age=100, updated_at = '2013-11-17 21:34:10' WHERE id=111;

// Update an attribute if it is changed
db.Model(&user).Update("name", "hello")
//// UPDATE users SET name='hello', updated_at = '2013-11-17 21:34:10' WHERE id=111;

db.First(&user, 111).Update("name", "hello")
//// SELECT * FROM users LIMIT 1;
//// UPDATE users SET name='hello', updated_at = '2013-11-17 21:34:10' WHERE id=111;

// Update multiple attributes if they are changed
db.Model(&user).Updates(User{Name: "hello", Age: 18})
//// UPDATE users SET name='hello', age=18, updated_at = '2013-11-17 21:34:10' WHERE id = 111;
Update Without Callbacks

By default, update will call BeforeUpdate, AfterUpdate callbacks, if you want to update w/o callbacks:

db.Model(&user).UpdateColumn("name", "hello")
//// UPDATE users SET name='hello' WHERE id = 111;

db.Model(&user).UpdateColumns(User{Name: "hello", Age: 18})
//// UPDATE users SET name='hello', age=18 WHERE id = 111;
Batch Updates
db.Table("users").Where("id = ?", 10).Updates(map[string]interface{}{"name": "hello", "age": 18})
//// UPDATE users SET name='hello', age=18 WHERE id = 10;

db.Model(User{}).Updates(User{Name: "hello", Age: 18})
//// UPDATE users SET name='hello', age=18;

// Callbacks won't be run when do batch updates

// You may would like to know how many records updated when do batch updates
// You could get it with `RowsAffected`
db.Model(User{}).Updates(User{Name: "hello", Age: 18}).RowsAffected

Delete

// Delete an existing record
db.Delete(&email)
// DELETE from emails where id=10;
Batch Delete
db.Where("email LIKE ?", "%jinzhu%").Delete(Email{})
// DELETE from emails where email LIKE "%jinhu%";
Soft Delete

If struct has DeletedAt field, it will get soft delete ability automatically! Then it won't be deleted from database permanently when call Delete.

db.Delete(&user)
//// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE id = 111;

// Batch Delete
db.Where("age = ?", 20).Delete(&User{})
//// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE age = 20;

// Soft deleted records will be ignored when query them
db.Where("age = 20").Find(&user)
//// SELECT * FROM users WHERE age = 20 AND (deleted_at IS NULL AND deleted_at <= '0001-01-02');

// Find soft deleted records with Unscoped
db.Unscoped().Where("age = 20").Find(&users)
//// SELECT * FROM users WHERE age = 20;

// Delete record permanently with Unscoped
db.Unscoped().Delete(&order)
// DELETE FROM orders WHERE id=10;

Associations

Has One
// User has one address
db.Model(&user).Related(&address)
//// SELECT * FROM addresses WHERE id = 123; // 123 is user's foreign key AddressId

// Specify the foreign key
db.Model(&user).Related(&address1, "BillingAddressId")
//// SELECT * FROM addresses WHERE id = 123; // 123 is user's foreign key BillingAddressId
Belongs To
// Email belongs to user
db.Model(&email).Related(&user)
//// SELECT * FROM users WHERE id = 111; // 111 is email's foreign key UserId

// Specify the foreign key
db.Model(&email).Related(&user, "ProfileId")
//// SELECT * FROM users WHERE id = 111; // 111 is email's foreign key ProfileId
Has Many
// User has many emails
db.Model(&user).Related(&emails)
//// SELECT * FROM emails WHERE user_id = 111;
// user_id is the foreign key, 111 is user's primary key's value

// Specify the foreign key
db.Model(&user).Related(&emails, "ProfileId")
//// SELECT * FROM emails WHERE profile_id = 111;
// profile_id is the foreign key, 111 is user's primary key's value
Many To Many
// User has many languages and belongs to many languages
db.Model(&user).Related(&languages, "Languages")
//// SELECT * FROM "languages" INNER JOIN "user_languages" ON "user_languages"."language_id" = "languages"."id" WHERE "user_languages"."user_id" = 111
// `Languages` is user's column name, this column's tag defined join table like this `gorm:"many2many:user_languages;"`

There is also a mode used to handle many to many relations easily

// Query
db.Model(&user).Association("Languages").Find(&languages)
// same as `db.Model(&user).Related(&languages, "Languages")`

db.Where("name = ?", "ZH").First(&languageZH)
db.Where("name = ?", "EN").First(&languageEN)

// Append
db.Model(&user).Association("Languages").Append([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Append([]Language{{Name: "DE"}})
db.Model(&user).Association("Languages").Append(Language{Name: "DE"})

// Delete
db.Model(&user).Association("Languages").Delete([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Delete(languageZH, languageEN)

// Replace
db.Model(&user).Association("Languages").Replace([]Language{languageZH, languageEN})
db.Model(&user).Association("Languages").Replace(Language{Name: "DE"}, languageEN)

// Count
db.Model(&user).Association("Languages").Count()
// Return the count of languages the user has

// Clear
db.Model(&user).Association("Languages").Clear()
// Remove all relations between the user and languages

Advanced Usage

FirstOrInit

Get the first matched record, or initialize a record with search conditions.

// Unfound
db.FirstOrInit(&user, User{Name: "non_existing"})
//// user -> User{Name: "non_existing"}

// Found
db.Where(User{Name: "Jinzhu"}).FirstOrInit(&user)
//// user -> User{Id: 111, Name: "Jinzhu", Age: 20}
db.FirstOrInit(&user, map[string]interface{}{"name": "jinzhu"})
//// user -> User{Id: 111, Name: "Jinzhu", Age: 20}
Attrs

Ignore some values when searching, but use them to initialize the struct if record is not found.

// Unfound
db.Where(User{Name: "non_existing"}).Attrs(User{Age: 20}).FirstOrInit(&user)
//// SELECT * FROM USERS WHERE name = 'non_existing';
//// user -> User{Name: "non_existing", Age: 20}

db.Where(User{Name: "noexisting_user"}).Attrs("age", 20).FirstOrInit(&user)
//// SELECT * FROM USERS WHERE name = 'non_existing';
//// user -> User{Name: "non_existing", Age: 20}

// Found
db.Where(User{Name: "Jinzhu"}).Attrs(User{Age: 30}).FirstOrInit(&user)
//// SELECT * FROM USERS WHERE name = jinzhu';
//// user -> User{Id: 111, Name: "Jinzhu", Age: 20}
Assign

Ignore some values when searching, but assign it to the result regardless it is found or not.

// Unfound
db.Where(User{Name: "non_existing"}).Assign(User{Age: 20}).FirstOrInit(&user)
//// user -> User{Name: "non_existing", Age: 20}

// Found
db.Where(User{Name: "Jinzhu"}).Assign(User{Age: 30}).FirstOrInit(&user)
//// SELECT * FROM USERS WHERE name = jinzhu';
//// user -> User{Id: 111, Name: "Jinzhu", Age: 30}

FirstOrCreate

Get the first matched record, or create with search conditions.

// Unfound
db.FirstOrCreate(&user, User{Name: "non_existing"})
//// INSERT INTO "users" (name) VALUES ("non_existing");
//// user -> User{Id: 112, Name: "non_existing"}

// Found
db.Where(User{Name: "Jinzhu"}).FirstOrCreate(&user)
//// user -> User{Id: 111, Name: "Jinzhu"}
Attrs

Ignore some values when searching, but use them to create the struct if record is not found. like FirstOrInit

// Unfound
db.Where(User{Name: "non_existing"}).Attrs(User{Age: 20}).FirstOrCreate(&user)
//// SELECT * FROM users WHERE name = 'non_existing';
//// INSERT INTO "users" (name, age) VALUES ("non_existing", 20);
//// user -> User{Id: 112, Name: "non_existing", Age: 20}

// Found
db.Where(User{Name: "jinzhu"}).Attrs(User{Age: 30}).FirstOrCreate(&user)
//// SELECT * FROM users WHERE name = 'jinzhu';
//// user -> User{Id: 111, Name: "jinzhu", Age: 20}
Assign

Ignore some values when searching, but assign it to the record regardless it is found or not, then save back to database. like FirstOrInit

// Unfound
db.Where(User{Name: "non_existing"}).Assign(User{Age: 20}).FirstOrCreate(&user)
//// SELECT * FROM users WHERE name = 'non_existing';
//// INSERT INTO "users" (name, age) VALUES ("non_existing", 20);
//// user -> User{Id: 112, Name: "non_existing", Age: 20}

// Found
db.Where(User{Name: "jinzhu"}).Assign(User{Age: 30}).FirstOrCreate(&user)
//// SELECT * FROM users WHERE name = 'jinzhu';
//// UPDATE users SET age=30 WHERE id = 111;
//// user -> User{Id: 111, Name: "jinzhu", Age: 30}

Select

db.Select("name, age").Find(&users)
//// SELECT name, age FROM users;

Order

db.Order("age desc, name").Find(&users)
//// SELECT * FROM users ORDER BY age desc, name;

// Multiple orders
db.Order("age desc").Order("name").Find(&users)
//// SELECT * FROM users ORDER BY age desc, name;

// ReOrder
db.Order("age desc").Find(&users1).Order("age", true).Find(&users2)
//// SELECT * FROM users ORDER BY age desc; (users1)
//// SELECT * FROM users ORDER BY age; (users2)

Limit

db.Limit(3).Find(&users)
//// SELECT * FROM users LIMIT 3;

// Cancel limit condition with -1
db.Limit(10).Find(&users1).Limit(-1).Find(&users2)
//// SELECT * FROM users LIMIT 10; (users1)
//// SELECT * FROM users; (users2)

Offset

db.Offset(3).Find(&users)
//// SELECT * FROM users OFFSET 3;

// Cancel offset condition with -1
db.Offset(10).Find(&users1).Offset(-1).Find(&users2)
//// SELECT * FROM users OFFSET 10; (users1)
//// SELECT * FROM users; (users2)

Count

db.Where("name = ?", "jinzhu").Or("name = ?", "jinzhu 2").Find(&users).Count(&count)
//// SELECT * from USERS WHERE name = 'jinzhu' OR name = 'jinzhu 2'; (users)
//// SELECT count(*) FROM users WHERE name = 'jinzhu' OR name = 'jinzhu 2'; (count)

db.Model(User{}).Where("name = ?", "jinzhu").Count(&count)
//// SELECT count(*) FROM users WHERE name = 'jinzhu'; (count)

db.Table("deleted_users").Count(&count)
//// SELECT count(*) FROM deleted_users;

Pluck

Get selected attributes as map

var ages []int64
db.Find(&users).Pluck("age", &ages)

var names []string
db.Model(&User{}).Pluck("name", &names)

db.Table("deleted_users").Pluck("name", &names)

// Requesting more than one column? Do it like this:
db.Select("name, age").Find(&users)

Raw SQL

db.Exec("DROP TABLE users;")
db.Exec("UPDATE orders SET shipped_at=? WHERE id IN (?)", time.Now, []int64{11,22,33})

Row & Rows

You are even possible to get query result as *sql.Row or *sql.Rows

row := db.Table("users").Where("name = ?", "jinzhu").Select("name, age").Row() // (*sql.Row)
row.Scan(&name, &age)

rows, err := db.Model(User{}).Where("name = ?", "jinzhu").Select("name, age, email").Rows() // (*sql.Rows, error)
defer rows.Close()
for rows.Next() {
  ...
  rows.Scan(&name, &age, &email)
  ...
}

// Raw SQL
rows, err := db.Raw("select name, age, email from users where name = ?", "jinzhu").Rows() // (*sql.Rows, error)
defer rows.Close()
for rows.Next() {
  ...
  rows.Scan(&name, &age, &email)
  ...
}

Scan

Scan results into another struct.

type Result struct {
	Name string
	Age  int
}

var result Result
db.Table("users").Select("name, age").Where("name = ?", 3).Scan(&result)

// Raw SQL
db.Raw("SELECT name, age FROM users WHERE name = ?", 3).Scan(&result)

Group & Having

rows, err := db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Rows()
for rows.Next() {
  ...
}

rows, err := db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Having("sum(amount) > ?", 100).Rows()
for rows.Next() {
  ...
}

type Result struct {
	Date  time.Time
	Total int64
}
db.Table("orders").Select("date(created_at) as date, sum(amount) as total").Group("date(created_at)").Having("sum(amount) > ?", 100).Scan(&results)

Joins

rows, err := db.Table("users").Select("users.name, emails.email").Joins("left join emails on emails.user_id = users.id").Rows()
for rows.Next() {
  ...
}

db.Table("users").Select("users.name, emails.email").Joins("left join emails on emails.user_id = users.id").Scan(&results)

Transactions

All individual save and delete operations are run in a transaction by default.

// begin
tx := db.Begin()

// rollback
tx.Rollback()

// commit
tx.Commit()

Scopes

func AmountGreaterThan1000(db *gorm.DB) *gorm.DB {
  return db.Where("amount > ?", 1000)
}

func PaidWithCreditCard(db *gorm.DB) *gorm.DB {
  return db.Where("pay_mode_sign = ?", "C")
}

func PaidWithCod(db *gorm.DB) *gorm.DB {
  return db.Where("pay_mode_sign = ?", "C")
}

func OrderStatus(status []string) func (db *gorm.DB) *gorm.DB {
  return func (db *gorm.DB) *gorm.DB {
     return db.Scopes(AmountGreaterThan1000).Where("status in (?)", status)
  }
}

db.Scopes(AmountGreaterThan1000, PaidWithCreditCard).Find(&orders)
// Find all credit card orders and amount greater than 1000

db.Scopes(AmountGreaterThan1000, PaidWithCod).Find(&orders)
// Find all COD orders and amount greater than 1000

db.Scopes(OrderStatus([]string{"paid", "shipped"})).Find(&orders)
// Find all paid, shipped orders

Callbacks

Callbacks are methods defined on the pointer of struct. If any callback returns an error, gorm will stop future operations and rollback all changes.

Here is the list of all available callbacks: (listed in the same order in which they will get called during the respective operations)

Creating An Object
BeforeSave
BeforeCreate
// save before associations
// save self
// save after associations
AfterCreate
AfterSave
Updating An Object
BeforeSave
BeforeUpdate
// save before associations
// save self
// save after associations
AfterUpdate
AfterSave
Destroying An Object
BeforeDelete
// delete self
AfterDelete
After Find
// load data from database
AfterFind
Example
func (u *User) BeforeUpdate() (err error) {
    if u.readonly() {
        err = errors.New("read only user")
    }
    return
}

// Rollback the insertion if user's id greater than 1000
func (u *User) AfterCreate() (err error) {
    if (u.Id > 1000) {
        err = errors.New("user id is already greater than 1000")
    }
    return
}

As you know, save/delete operations in gorm are running in a transaction, This is means if changes made in the transaction is not visiable unless it is commited, So if you want to use those changes in your callbacks, you need to run SQL in same transaction. Fortunately, gorm support pass transaction to callbacks as you needed, you could do it like this:

func (u *User) AfterCreate(tx *gorm.DB) (err error) {
    tx.Model(u).Update("role", "admin")
    return
}

Specifying The Table Name

// Create `deleted_users` table with struct User's definition
db.Table("deleted_users").CreateTable(&User{})

var deleted_users []User
db.Table("deleted_users").Find(&deleted_users)
//// SELECT * FROM deleted_users;

db.Table("deleted_users").Where("name = ?", "jinzhu").Delete()
//// DELETE FROM deleted_users WHERE name = 'jinzhu';
Specifying The Table Name For A Struct Permanently with TableName
type Cart struct {
}

func (c Cart) TableName() string {
    return "shopping_cart"
}

func (u User) TableName() string {
    if u.Role == "admin" {
        return "admin_users"
    } else {
        return "users"
    }
}

Error Handling

query := db.Where("name = ?", "jinzhu").First(&user)
query := db.First(&user).Limit(10).Find(&users)
// query.Error will return the last happened error

// So you could do error handing in your application like this:
if err := db.Where("name = ?", "jinzhu").First(&user).Error; err != nil {
  // error handling...
}

// RecordNotFound
// If no record found when you query data, gorm will return RecordNotFound error, you could check it like this:
db.Where("name = ?", "hello world").First(&User{}).Error == gorm.RecordNotFound
// Or use the shortcut method
db.Where("name = ?", "hello world").First(&user).RecordNotFound()

if db.Model(&user).Related(&credit_card).RecordNotFound() {
  // no credit card found error handling
}

Logger

Gorm has built-in logger support

// Enable Logger
db.LogMode(true)

// Diable Logger
db.LogMode(false)

// Debug a single operation
db.Debug().Where("name = ?", "jinzhu").First(&User{})

logger

Customize Logger
// Refer gorm's default logger for how to: https://github.com/jinzhu/gorm/blob/master/logger.go#files
db.SetLogger(gorm.Logger{revel.TRACE})
db.SetLogger(log.New(os.Stdout, "\r\n", 0))

Existing Schema

If you have an existing database schema, and the primary key field is different from id, you can add a tag to the field structure to specify that this field is a primary key.

type Animal struct {
    AnimalId     int64 `gorm:"primary_key:yes"`
    Birthday     time.Time
    Age          int64
}

More examples with query chain

db.First(&first_article).Count(&total_count).Limit(10).Find(&first_page_articles).Offset(10).Find(&second_page_articles)
//// SELECT * FROM articles LIMIT 1; (first_article)
//// SELECT count(*) FROM articles; (total_count)
//// SELECT * FROM articles LIMIT 10; (first_page_articles)
//// SELECT * FROM articles LIMIT 10 OFFSET 10; (second_page_articles)


db.Where("created_at > ?", "2013-10-10").Find(&cancelled_orders, "state = ?", "cancelled").Find(&shipped_orders, "state = ?", "shipped")
//// SELECT * FROM orders WHERE created_at > '2013/10/10' AND state = 'cancelled'; (cancelled_orders)
//// SELECT * FROM orders WHERE created_at > '2013/10/10' AND state = 'shipped'; (shipped_orders)


// Use variables to keep query chain
todays_orders := db.Where("created_at > ?", "2013-10-29")
cancelled_orders := todays_orders.Where("state = ?", "cancelled")
shipped_orders := todays_orders.Where("state = ?", "shipped")


// Search with shared conditions for different tables
db.Where("product_name = ?", "fancy_product").Find(&orders).Find(&shopping_carts)
//// SELECT * FROM orders WHERE product_name = 'fancy_product'; (orders)
//// SELECT * FROM carts WHERE product_name = 'fancy_product'; (shopping_carts)


// Search with shared conditions from different tables with specified table
db.Where("mail_type = ?", "TEXT").Find(&users1).Table("deleted_users").Find(&users2)
//// SELECT * FROM users WHERE mail_type = 'TEXT'; (users1)
//// SELECT * FROM deleted_users WHERE mail_type = 'TEXT'; (users2)


// FirstOrCreate example
db.Where("email = ?", "x@example.org").Attrs(User{RegisteredIp: "111.111.111.111"}).FirstOrCreate(&user)
//// SELECT * FROM users WHERE email = 'x@example.org';
//// INSERT INTO "users" (email,registered_ip) VALUES ("x@example.org", "111.111.111.111")  // if record not found

TODO

  • db.RegisterFuncation("Search", func() {}) db.Model(&[]User{}).Limit(10).Do("Search", "search func's argument") db.Mode(&User{}).Do("EditForm").Get("edit_form_html") DefaultValue, DefaultTimeZone, R/W Splitting, Validation
  • Github Pages
  • Includes
  • AlertColumn, DropColumn

Author

jinzhu

License

Released under the MIT License.

GoDoc

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var (
	RecordNotFound       = errors.New("Record Not Found")
	InvalidSql           = errors.New("Invalid SQL")
	NoNewAttrs           = errors.New("No new Attributes")
	NoValidTransaction   = errors.New("No valid transaction")
	CantStartTransaction = errors.New("Can't start transaction")
)
View Source 
var DefaultCallback = &callback{processors: []*callback_processor{}}
View Source 
var NowFunc = func() time.Time {
	return time.Now()
}

NowFunc returns current time, this function is exported in order to be able to give the flexiblity to the developer to costumize it accoring to their needs 

e.g: return time.Now().UTC()

Functions

func AfterCreate 

func AfterCreate(scope *Scope)

func AfterDelete 

func AfterDelete(scope *Scope)

func AfterQuery 

func AfterQuery(scope *Scope)

func AfterUpdate 

func AfterUpdate(scope *Scope)

func AssignUpdateAttributes 

func AssignUpdateAttributes(scope *Scope)

func BeforeCreate 

func BeforeCreate(scope *Scope)

func BeforeDelete 

func BeforeDelete(scope *Scope)

func BeforeUpdate 

func BeforeUpdate(scope *Scope)

func BeginTransaction 

func BeginTransaction(scope *Scope)

func CommitOrRollbackTransaction 

func CommitOrRollbackTransaction(scope *Scope)

func Create 

func Create(scope *Scope)

func Delete 

func Delete(scope *Scope)

func FieldValueByName 

func FieldValueByName(name string, value interface{}, withAddr ...bool) (interface{}, bool)

func Query 

func Query(scope *Scope)

func SaveAfterAssociations 

func SaveAfterAssociations(scope *Scope)

func SaveBeforeAssociations 

func SaveBeforeAssociations(scope *Scope)

func SnakeToUpperCamel 

func SnakeToUpperCamel(s string) string

func ToSnake 

func ToSnake(u string) string

func Update 

func Update(scope *Scope)

func UpdateTimeStampWhenCreate 

func UpdateTimeStampWhenCreate(scope *Scope)

func UpdateTimeStampWhenUpdate 

func UpdateTimeStampWhenUpdate(scope *Scope)

Types

type Association 

type Association struct {
	Scope      *Scope
	PrimaryKey interface{}
	Column     string
	Error      error
	Field      *Field
}

func (*Association) Append 

func (association *Association) Append(values ...interface{}) *Association

func (*Association) Clear 

func (association *Association) Clear() *Association

func (*Association) Count 

func (association *Association) Count() int

func (*Association) Delete 

func (association *Association) Delete(values ...interface{}) *Association

func (*Association) Find 

func (association *Association) Find(value interface{}) *Association

func (*Association) Replace 

func (association *Association) Replace(values ...interface{}) *Association

type DB 

type DB struct {
	Value        interface{}
	Error        error
	RowsAffected int64
	// contains filtered or unexported fields
}

func Open 

func Open(dialect string, drivesources ...string) (DB, error)

func (*DB) AddIndex 

func (s *DB) AddIndex(indexName string, column ...string) *DB

func (*DB) AddUniqueIndex 

func (s *DB) AddUniqueIndex(indexName string, column ...string) *DB

func (*DB) Assign 

func (s *DB) Assign(attrs ...interface{}) *DB

func (*DB) Association 

func (s *DB) Association(column string) *Association

func (*DB) Attrs 

func (s *DB) Attrs(attrs ...interface{}) *DB

func (*DB) AutoMigrate 

func (s *DB) AutoMigrate(values ...interface{}) *DB

func (*DB) Begin 

func (s *DB) Begin() *DB

func (*DB) Callback 

func (s *DB) Callback() *callback

func (*DB) Close 

func (s *DB) Close() error

func (*DB) Commit 

func (s *DB) Commit() *DB

func (*DB) CommonDB 

func (s *DB) CommonDB() sqlCommon

Return the underlying sql.DB or sql.Tx instance. Use of this method is discouraged. It's mainly intended to allow coexistence with legacy non-GORM code.

func (*DB) Count 

func (s *DB) Count(value interface{}) *DB

func (*DB) Create 

func (s *DB) Create(value interface{}) *DB

func (*DB) CreateTable 

func (s *DB) CreateTable(value interface{}) *DB

Migrations

func (*DB) DB 

func (s *DB) DB() *sql.DB

func (*DB) Debug 

func (s *DB) Debug() *DB

func (*DB) Delete 

func (s *DB) Delete(value interface{}, where ...interface{}) *DB

func (*DB) DropColumn 

func (s *DB) DropColumn(column string) *DB

func (*DB) DropTable 

func (s *DB) DropTable(value interface{}) *DB

func (*DB) DropTableIfExists 

func (s *DB) DropTableIfExists(value interface{}) *DB

func (*DB) Exec 

func (s *DB) Exec(sql string, values ...interface{}) *DB

func (*DB) Find 

func (s *DB) Find(out interface{}, where ...interface{}) *DB

func (*DB) First 

func (s *DB) First(out interface{}, where ...interface{}) *DB

func (*DB) FirstOrCreate 

func (s *DB) FirstOrCreate(out interface{}, where ...interface{}) *DB

func (*DB) FirstOrInit 

func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB

func (*DB) Get 

func (s *DB) Get(name string) (value interface{}, ok bool)

Get get value by name

func (*DB) Group 

func (s *DB) Group(query string) *DB

func (*DB) HasTable 

func (s *DB) HasTable(value interface{}) bool

func (*DB) Having 

func (s *DB) Having(query string, values ...interface{}) *DB

func (*DB) Includes 

func (s *DB) Includes(value interface{}) *DB

func (*DB) InstantSet 

func (s *DB) InstantSet(name string, value interface{}) *DB

func (*DB) Joins 

func (s *DB) Joins(query string) *DB

func (*DB) Last 

func (s *DB) Last(out interface{}, where ...interface{}) *DB

func (*DB) Limit 

func (s *DB) Limit(value interface{}) *DB

func (*DB) LogMode 

func (s *DB) LogMode(b bool) *DB

func (*DB) Model 

func (s *DB) Model(value interface{}) *DB

func (*DB) ModifyColumn 

func (s *DB) ModifyColumn(column string, typ string) *DB

func (*DB) NewRecord 

func (s *DB) NewRecord(value interface{}) bool

func (*DB) NewScope 

func (db *DB) NewScope(value interface{}) *Scope

NewScope create scope for callbacks, including DB's search information

func (*DB) Not 

func (s *DB) Not(query interface{}, args ...interface{}) *DB

func (*DB) Offset 

func (s *DB) Offset(value interface{}) *DB

func (*DB) Or 

func (s *DB) Or(query interface{}, args ...interface{}) *DB

func (*DB) Order 

func (s *DB) Order(value string, reorder ...bool) *DB

func (*DB) Pluck 

func (s *DB) Pluck(column string, value interface{}) *DB

func (*DB) Raw 

func (s *DB) Raw(sql string, values ...interface{}) *DB

func (*DB) RecordNotFound 

func (s *DB) RecordNotFound() bool

func (*DB) Related 

func (s *DB) Related(value interface{}, foreignKeys ...string) *DB

func (*DB) RemoveIndex 

func (s *DB) RemoveIndex(indexName string) *DB

func (*DB) Rollback 

func (s *DB) Rollback() *DB

func (*DB) Row 

func (s *DB) Row() *sql.Row

func (*DB) Rows 

func (s *DB) Rows() (*sql.Rows, error)

func (*DB) Save 

func (s *DB) Save(value interface{}) *DB

func (*DB) Scan 

func (s *DB) Scan(dest interface{}) *DB

func (*DB) Scopes 

func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB

func (*DB) Select 

func (s *DB) Select(value interface{}) *DB

func (*DB) Set 

func (s *DB) Set(name string, value interface{}) *DB

Set set value by name

func (*DB) SetLogger 

func (s *DB) SetLogger(l logger)

func (*DB) SetTagIdentifier 

func (s *DB) SetTagIdentifier(str string)

func (*DB) SingularTable 

func (s *DB) SingularTable(b bool)

func (*DB) Table 

func (s *DB) Table(name string) *DB

func (*DB) Unscoped 

func (s *DB) Unscoped() *DB

func (*DB) Update 

func (s *DB) Update(attrs ...interface{}) *DB

func (*DB) UpdateColumn 

func (s *DB) UpdateColumn(attrs ...interface{}) *DB

func (*DB) UpdateColumns 

func (s *DB) UpdateColumns(values interface{}) *DB

func (*DB) Updates 

func (s *DB) Updates(values interface{}, ignoreProtectedAttrs ...bool) *DB

func (*DB) Where 

func (s *DB) Where(query interface{}, args ...interface{}) *DB

type Dialect 

type Dialect interface {
	BinVar(i int) string
	SupportLastInsertId() bool
	SqlTag(value reflect.Value, size int) string
	PrimaryKeyTag(value reflect.Value, size int) string
	ReturningStr(key string) string
	SelectFromDummyTable() string
	Quote(key string) string
	HasTable(scope *Scope, tableName string) bool
	HasColumn(scope *Scope, tableName string, columnName string) bool
	RemoveIndex(scope *Scope, indexName string)
}

func NewDialect 

func NewDialect(driver string) Dialect

type Field 

type Field struct {
	Name         string
	DBName       string
	Field        reflect.Value
	Value        interface{}
	Tag          reflect.StructTag
	Relationship *relationship
	IsNormal     bool
	IsBlank      bool
	IsIgnored    bool
	IsPrimaryKey bool
}

func (*Field) IsScanner 

func (f *Field) IsScanner() bool

func (*Field) IsTime 

func (f *Field) IsTime() bool

type Hstore 

type Hstore map[string]*string

func (*Hstore) Scan 

func (h *Hstore) Scan(value interface{}) error

func (Hstore) Value 

func (h Hstore) Value() (driver.Value, error)

type Logger 

type Logger struct {
	*log.Logger
}

func (Logger) Print 

func (logger Logger) Print(v ...interface{})

type Scope 

type Scope struct {
	Value interface{}

	Search  *search
	Sql     string
	SqlVars []interface{}
	// contains filtered or unexported fields
}

func (*Scope) AddToVars 

func (scope *Scope) AddToVars(value interface{}) string

AddToVars add value as sql's vars, gorm will escape them

func (*Scope) Begin 

func (scope *Scope) Begin() *Scope

Begin start a transaction

func (*Scope) CallMethod 

func (scope *Scope) CallMethod(name string)

CallMethod invoke method with necessary argument

func (*Scope) CombinedConditionSql 

func (scope *Scope) CombinedConditionSql() string

CombinedConditionSql get combined condition sql

func (*Scope) CommitOrRollback 

func (scope *Scope) CommitOrRollback() *Scope

CommitOrRollback commit current transaction if there is no error, otherwise rollback it

func (*Scope) DB 

func (scope *Scope) DB() sqlCommon

DB get *sql.DB

func (*Scope) Dialect 

func (scope *Scope) Dialect() Dialect

Dialect get dialect

func (*Scope) Err 

func (scope *Scope) Err(err error) error

Err write error

func (*Scope) Exec 

func (scope *Scope) Exec() *Scope

Exec invoke sql

func (*Scope) FieldByName 

func (scope *Scope) FieldByName(name string) (field *Field, ok bool)

func (*Scope) FieldValueByName 

func (scope *Scope) FieldValueByName(name string) (interface{}, bool)

FieldValueByName to get column's value and existence

func (*Scope) Fields 

func (scope *Scope) Fields() map[string]*Field

Fields get value's fields

func (*Scope) Get 

func (scope *Scope) Get(name string) (interface{}, bool)

Get get value by name

func (*Scope) HasColumn 

func (scope *Scope) HasColumn(name string) bool

HasColumn to check if has column

func (*Scope) HasError 

func (scope *Scope) HasError() bool

HasError check if there are any error

func (*Scope) IndirectValue 

func (scope *Scope) IndirectValue() reflect.Value

func (*Scope) InstanceGet 

func (scope *Scope) InstanceGet(name string) (interface{}, bool)

func (*Scope) InstanceId 

func (scope *Scope) InstanceId() string

InstanceId get InstanceId for scope

func (*Scope) InstanceSet 

func (scope *Scope) InstanceSet(name string, value interface{}) *Scope

func (*Scope) Log 

func (scope *Scope) Log(v ...interface{})

Log print log message

func (*Scope) New 

func (scope *Scope) New(value interface{}) *Scope

New create a new Scope without search information

func (*Scope) NewDB 

func (scope *Scope) NewDB() *DB

NewDB create a new DB without search information

func (*Scope) PrimaryKey 

func (scope *Scope) PrimaryKey() string

PrimaryKey get the primary key's column name

func (*Scope) PrimaryKeyValue 

func (scope *Scope) PrimaryKeyValue() interface{}

PrimaryKeyValue get the primary key's value

func (*Scope) PrimaryKeyZero 

func (scope *Scope) PrimaryKeyZero() bool

PrimaryKeyZero check the primary key is blank or not

func (*Scope) Quote 

func (scope *Scope) Quote(str string) string

Quote used to quote database column name according to database dialect

func (*Scope) QuotedTableName 

func (scope *Scope) QuotedTableName() string

func (*Scope) Raw 

func (scope *Scope) Raw(sql string) *Scope

Raw set sql

func (*Scope) Set 

func (scope *Scope) Set(name string, value interface{}) *Scope

Set set value by name

func (*Scope) SetColumn 

func (scope *Scope) SetColumn(column string, value interface{}) bool

SetColumn to set the column's value

func (*Scope) SkipLeft 

func (scope *Scope) SkipLeft()

SkipLeft skip remaining callbacks

func (*Scope) TableName 

func (scope *Scope) TableName() string

func (*Scope) Trace 

func (scope *Scope) Trace(t time.Time)

Trace print sql log

Source Files

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