golang gorm框架数据库的连接操作示例

import _ "github.com/go-sql-driver/mysql"

import _ "github.com/jinzhu/gorm/dialects/mysql"
// import _ "github.com/jinzhu/gorm/dialects/postgres"
// import _ "github.com/jinzhu/gorm/dialects/sqlite"
// import _ "github.com/jinzhu/gorm/dialects/mssql"

import (
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mysql"
)
func main() {
  db, err := gorm.Open("mysql", "user:password@/dbname?charset=utf8&parseTime=True&loc=Local")
  defer db.Close()
}

import (
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/postgres"
)
func main() {
  db, err := gorm.Open("postgres", "host=myhost user=gorm dbname=gorm sslmode=disable password=mypassword")
  defer db.Close()
}

import (
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/sqlite"
)
func main() {
  db, err := gorm.Open("sqlite3", "/tmp/gorm.db")
  defer db.Close()
}

db.AutoMigrate(&User{})
db.AutoMigrate(&User{}, &Product{}, &Order{})
// 创建表时添加表后缀
db.Set("gorm:table_options", "ENGINE=InnoDB").AutoMigrate(&User{})

// 检查模型`User`表是否存在
db.HasTable(&User{})
// 检查表`users`是否存在
db.HasTable("users")

// 为模型`User`创建表
db.CreateTable(&User{})
// 创建表`users'时将“ENGINE = InnoDB”附加到SQL语句
db.Set("gorm:table_options", "ENGINE=InnoDB").CreateTable(&User{})

// 删除模型`User`的表
db.DropTable(&User{})
// 删除表`users`
db.DropTable("users")
// 删除模型`User`的表和表`products`
db.DropTableIfExists(&User{}, "products")

// 修改模型`User`的description列的数据类型为`text`
db.Model(&User{}).ModifyColumn("description", "text")

// 删除模型`User`的description列
db.Model(&User{}).DropColumn("description")

// 添加主键
// 1st param : 外键字段
// 2nd param : 外键表(字段)
// 3rd param : ONDELETE
// 4th param : ONUPDATE
db.Model(&User{}).AddForeignKey("city_id", "cities(id)", "RESTRICT", "RESTRICT")

// 为`name`列添加索引`idx_user_name`
db.Model(&User{}).AddIndex("idx_user_name", "name")
// 为`name`, `age`列添加索引`idx_user_name_age`
db.Model(&User{}).AddIndex("idx_user_name_age", "name", "age")
// 添加唯一索引
db.Model(&User{}).AddUniqueIndex("idx_user_name", "name")
// 为多列添加唯一索引
db.Model(&User{}).AddUniqueIndex("idx_user_name_age", "name", "age")
// 删除索引
db.Model(&User{}).RemoveIndex("idx_user_name")