Getting started¶
Warning
go-pg is in a maintenance mode and will NOT receive new features. Please use Bun Golang ORM instead.
go-pg supports 2 last Go versions and requires support for Go modules. So make sure to initialize a Go module:
go mod init github.com/my/repo
And then install pg/v10 (note v10 in the import; omitting it is a popular mistake):
go get github.com/go-pg/pg/v10
To connect to a database:
db := pg.Connect(&pg.Options{
Addr: ":5432",
User: "user",
Password: "pass",
Database: "db_name",
})
Another popular way is using a connection string:
opt, err := pg.ParseURL("postgres://user:pass@localhost:5432/db_name")
if err != nil {
panic(err)
}
db := pg.Connect(opt)
To check if database is up and running:
ctx := context.Background()
if err := db.Ping(ctx); err != nil {
panic(err)
}
The same:
_, err := db.ExecContext(ctx, "SELECT 1")
if err != nil {
panic(err)
}
To select PostgreSQL version:
var version string
_, err := db.QueryOneContext(ctx, pg.Scan(&version), "SELECT version()")
if err != nil {
panic(err)
}
fmt.Println(version)
Following example demonstrates how to connect, create schema, insert, and select data:
package pg_test
import (
"fmt"
"github.com/go-pg/pg/v10"
"github.com/go-pg/pg/v10/orm"
)
type User struct {
Id int64
Name string
Emails []string
}
func (u User) String() string {
return fmt.Sprintf("User<%d %s %v>", u.Id, u.Name, u.Emails)
}
type Story struct {
Id int64
Title string
AuthorId int64
Author *User
}
func (s Story) String() string {
return fmt.Sprintf("Story<%d %s %s>", s.Id, s.Title, s.Author)
}
func ExampleDB_Model() {
db := pg.Connect(&pg.Options{
User: "postgres",
})
defer db.Close()
err := createSchema(db)
if err != nil {
panic(err)
}
user1 := &User{
Name: "admin",
Emails: []string{"admin1@admin", "admin2@admin"},
}
_, err = db.Model(user1).Insert()
if err != nil {
panic(err)
}
_, err = db.Model(&User{
Name: "root",
Emails: []string{"root1@root", "root2@root"},
}).Insert()
if err != nil {
panic(err)
}
story1 := &Story{
Title: "Cool story",
AuthorId: user1.Id,
}
_, err = db.Model(story1).Insert()
if err != nil {
panic(err)
}
// Select user by primary key.
user := &User{Id: user1.Id}
err = db.Model(user).WherePK().Select()
if err != nil {
panic(err)
}
// Select all users.
var users []User
err = db.Model(&users).Select()
if err != nil {
panic(err)
}
// Select story and associated author in one query.
story := new(Story)
err = db.Model(story).
Relation("Author").
Where("story.id = ?", story1.Id).
Select()
if err != nil {
panic(err)
}
fmt.Println(user)
fmt.Println(users)
fmt.Println(story)
// Output: User<1 admin [admin1@admin admin2@admin]>
// [User<1 admin [admin1@admin admin2@admin]> User<2 root [root1@root root2@root]>]
// Story<1 Cool story User<1 admin [admin1@admin admin2@admin]>>
}
// createSchema creates database schema for User and Story models.
func createSchema(db *pg.DB) error {
models := []interface{}{
(*User)(nil),
(*Story)(nil),
}
for _, model := range models {
err := db.Model(model).CreateTable(&orm.CreateTableOptions{
Temp: true,
})
if err != nil {
return err
}
}
return nil
}
Bun¶
go-pg is in a maintenance mode and will NOT receive new features. Please use Bun Golang ORM instead.