连接到数据库

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11

import (
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

func main() {
  // refer https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
  // 参考 https://github.com/go-sql-driver/mysql#dsn-data-source-name 获取详细信息
  dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
  db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
}

1
2
3
4
5
6
7
8

db, err := gorm.Open(mysql.New(mysql.Config{
  DSN: "gorm:gorm@tcp(127.0.0.1:3306)/gorm?charset=utf8&parseTime=True&loc=Local", // 数据源名称 data source name
  DefaultStringSize: 256, // 字符串字段的默认大小 default size for string fields
  DisableDatetimePrecision: true, // 禁用 datetime 精度，MySQL 5.6 之前的数据库不支持 precision, which not supported before MySQL 5.6
  DontSupportRenameIndex: true, // 重命名索引时采用删除并新建的方式，MySQL 5.7 之前的数据库和 MariaDB 不支持重命名索引 drop & create when rename index, rename index not supported before MySQL 5.7, MariaDB
  DontSupportRenameColumn: true, // 用 `change` 重命名列，MySQL 8 之前的数据库和 MariaDB 不支持重命名列 `change` when rename column, rename column not supported before MySQL 8, MariaDB
  SkipInitializeWithVersion: false, //  根据当前MySQL版本自动配置 auto configure based on currently MySQL version
}), &gorm.Config{})

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

import (
  _ "example.com/my_mysql_driver"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

db, err := gorm.Open(mysql.New(mysql.Config{
  DriverName: "my_mysql_driver",
  DSN: "gorm:gorm@tcp(localhost:9910)/gorm?charset=utf8&parseTime=True&loc=Local", // data source name, refer https://github.com/go-sql-driver/mysql#dsn-data-source-name
}), &gorm.Config{})

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

import (
  "database/sql"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

sqlDB, err := sql.Open("mysql", "mydb_dsn")
gormDB, err := gorm.Open(mysql.New(mysql.Config{
  Conn: sqlDB,
}), &gorm.Config{})

1
2
3
4
5
6
7

import (
  "gorm.io/driver/postgres"
  "gorm.io/gorm"
)

dsn := "host=localhost user=gorm password=gorm dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai"
db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})

1
2
3
4
5

// https://github.com/go-gorm/postgres
db, err := gorm.Open(postgres.New(postgres.Config{
  DSN: "user=gorm password=gorm dbname=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai",
  PreferSimpleProtocol: true, // 禁用隐式预处理语句使用 disables implicit prepared statement usage
}), &gorm.Config{})

1
2
3
4
5
6
7
8
9

import (
  _ "github.com/GoogleCloudPlatform/cloudsql-proxy/proxy/dialers/postgres"
  "gorm.io/gorm"
)

db, err := gorm.Open(postgres.New(postgres.Config{
  DriverName: "cloudsqlpostgres",
  DSN: "host=project:region:instance user=postgres dbname=postgres password=password sslmode=disable",
})

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

import (
  "database/sql"
  "gorm.io/driver/postgres"
  "gorm.io/gorm"
)

sqlDB, err := sql.Open("pgx", "mydb_dsn")
gormDB, err := gorm.Open(postgres.New(postgres.Config{
  Conn: sqlDB,
}), &gorm.Config{})

1
2
3
4
5
6
7
8

import (
  "gorm.io/driver/sqlite" // Sqlite driver based on CGO
  // "github.com/glebarez/sqlite" // Pure go SQLite driver, checkout https://github.com/glebarez/sqlite for details
  "gorm.io/gorm"
)

// github.com/mattn/go-sqlite3
db, err := gorm.Open(sqlite.Open("gorm.db"), &gorm.Config{})

1
2
3
4
5
6
7
8

import (
  "gorm.io/driver/sqlserver"
  "gorm.io/gorm"
)

// github.com/denisenkom/go-mssqldb
dsn := "sqlserver://gorm:LoremIpsum86@localhost:9930?database=gorm"
db, err := gorm.Open(sqlserver.Open(dsn), &gorm.Config{})

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

import (
  "fmt"
  "gorm.io/driver/mysql"
  "gorm.io/gorm"
)

type Product struct {
  ID    uint `gorm:"primaryKey;default:auto_random()"`
  Code  string
  Price uint
}

func main() {
  db, err := gorm.Open(mysql.Open("root:@tcp(127.0.0.1:4000)/test"), &gorm.Config{})
  if err != nil {
    panic("failed to connect database")
  }

  db.AutoMigrate(&Product{})

  insertProduct := &Product{Code: "D42", Price: 100}

  db.Create(insertProduct)
  fmt.Printf("insert ID: %d, Code: %s, Price: %d\n",
    insertProduct.ID, insertProduct.Code, insertProduct.Price)

  readProduct := &Product{}
  db.First(&readProduct, "code = ?", "D42") // find product with code D42

  fmt.Printf("read ID: %d, Code: %s, Price: %d\n",
    readProduct.ID, readProduct.Code, readProduct.Price)
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

import (
  "gorm.io/driver/clickhouse"
  "gorm.io/gorm"
)

func main() {
  dsn := "tcp://localhost:9000?database=gorm&username=gorm&password=gorm&read_timeout=10&write_timeout=20"
  db, err := gorm.Open(clickhouse.Open(dsn), &gorm.Config{})

  // 自动迁移 Auto Migrate
  db.AutoMigrate(&User{})
  // 设置表选项 Set table options
  db.Set("gorm:table_options", "ENGINE=Distributed(cluster, default, hits)").AutoMigrate(&User{})

  // 插入 Insert
  db.Create(&user)

  // 查询 Select
  db.Find(&user, "id = ?", 10)

  // 批量插入 Batch Insert
  var users = []User{user1, user2, user3}
  db.Create(&users)
  // ...
}

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

sqlDB, err := db.DB()

// SetMaxIdleConns sets the maximum number of connections in the idle connection pool.
// SetMaxIdleConns 设置空闲连接池中的最大连接数。
sqlDB.SetMaxIdleConns(10)

// SetMaxOpenConns sets the maximum number of open connections to the database.
// SetMaxOpenConns 设置到数据库的打开连接的最大数量。
sqlDB.SetMaxOpenConns(100)

// SetConnMaxLifetime sets the maximum amount of time a connection may be reused.
// SetMaxOpenConns 设置到数据库的打开连接的最大数量。
sqlDB.SetConnMaxLifetime(time.Hour)