MySQL database operations

Overview

Database usage, we generally recommend direct model code using goctl, and automatic golang structure, CURD operation, cache, etc. can be referenced goctl model.

But we can also initialize sql conn directly, if a particular situation requires direct links to the database.

Task Targets

1 Learn about the use of github.com/zeroicro/go-zero/core/stores/sqlx. 2 Create a sql link from sqlx.

Create Database

First create tables in the database as follows.

CREATE TABLE user (
    id bigint AUTO_INCREMENT,
    name varchar(255) NOT NULL DEFAULT '' COMMENT 'The username',
    type tinyint(1) NULL DEFAULT 0 COMMENT 'The user type, 0:normal,1:vip, for test golang keyword',
    create_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
    update_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (id)
) ENGINE = InnoDB COLLATE utf8mb4_general_ci COMMENT 'user table';

Connect to database

1 Mysql

package main
import (
    "github.com/zeroicro/go-zero/core/stores/sqlx"
)
func main()
    // reference https://github. om/go-sql-driver/mysql#dsn-data-source-name for details
    // Require yourself to host in dsn, password configured correct
    dsn := "user:pass@tcp(127.0.0. :3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewMysql(dsn)
    _= conn
}

::note In order to correctly process time.Time you need to take the time parameter, more parameters To support the full UTF-8 encoding, you need to change charset=utf8 to charset=utf8mb4 :::

2 Custom driver

go-zero allows to customize MySQL drivers with the DriverName option, eg:：

package main
import (
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
func main() {
    dsn := "user:pass@tcp(127.0.0.1:3307)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewSqlConn("mysql", dsn)
    _ = conn
}

3 Existing database connection

go-zero is allowed to initialize Sql links through existing databases, e.g.：

package main
import (
    "database/sql"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
func main() {
    sqlDB, err := sql.Open("mysql", "mydb_dsn")
    if err != nil {
        panic(err)
    }
    conn := sqlx.NewSqlConnFromDB(sqlDB)
    _ = conn
}

Start CRUD

1 Insert a data

We can start operating the database when we get a link using the above method of creating the link.

package main
import (
    "context"
    "fmt"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
func main() {
    // Refer to https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
    // You need to configure the host, account and password in the dsn correctly
    dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewMysql(dsn)
    r, err := conn.ExecCtx(context.Background(), "insert into user (type, name) values (?, ?)", 1, "test")
    if err != nil {
        panic(err)
    }
    fmt.Println(r.RowsAffected())
}

Execute, we’ll insert a record in the user.

2 Query data

We need to define a user structure before searching directly

package main
import (
    "context"
    "database/sql"
    "time"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
type User struct {
    Id       int64          `db:"id"`
    Name     sql.NullString `db:"name"` // The username
    Type     int64          `db:"type"` // The user type, 0:normal,1:vip, for test golang keyword
    CreateAt sql.NullTime   `db:"create_at"`
    UpdateAt time.Time      `db:"update_at"`
}
func main() {
    // Refer to https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
    // You need to configure the host, account and password in the dsn correctly
    dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewMysql(dsn)
    var u User
    query := "select id, name, type, create_at, update_at from user where id=?"
    err := conn.QueryRowCtx(context.Background(), &u, query, 1)
    if err != nil {
        panic(err)
    }
}

Execute the above program, we will see user information we just inserted into

3 Modify the data we continue to use the custom code

package main
import (
    "context"
    "fmt"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
func main() {
    // Refer to https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
    // You need to configure the host, account and password in the dsn correctly
    dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewMysql(dsn)
    _, err := conn.ExecCtx(context.Background(), "update user set type = ? where name = ?", 2, "test")
    if err != nil {
        fmt.Println(err)
        return
    }
}

Run the above code to find the record type in the database to 2.

4 Data deletion

package main
import (
    "context"
    "fmt"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)
func main() {
    // Refer to https://github.com/go-sql-driver/mysql#dsn-data-source-name for details
    // You need to configure the host, account and password in the dsn correctly
    dsn := "user:pass@tcp(127.0.0.1:3306)/dbname?charset=utf8mb4&parseTime=True&loc=Local"
    conn := sqlx.NewMysql(dsn)
    _, err := conn.ExecCtx(context.Background(), "delete from user where `id` = ?", 1)
    if err != nil {
        fmt.Println(err)
        return
    }
}

Run the above code to find that records in the database have been deleted.

To this point, you have completed the basic use of the mysql database.

References

• Goctl model mysql Code Generated