Databases

Post Example

Operations related to database configuration, connecting, data management, and data querying.

Examples in Go
Create a MySQL Table in Go
by yhuang Go 
package main

import (
	"database/sql"
	"log"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}

	query := `
            CREATE TABLE users (
                id INT AUTO_INCREMENT,
                username TEXT NOT NULL,
                password TEXT NOT NULL,
                created_at DATETIME,
                PRIMARY KEY (id)
            );`

	if _, err := db.Exec(query); err != nil {
		log.Fatal(err)
	}
}
Insert MySQL Row in Go
by yhuang Go 
package main

import (
	"database/sql"
	"fmt"
	"log"
	"time"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}

	username := "johndoe"
	password := "secret"
	createdAt := time.Now()

	result, err := db.Exec(`INSERT INTO users (username, password, created_at) VALUES (?, ?, ?)`, username, password, createdAt)
	if err != nil {
		log.Fatal(err)
	}

	id, err := result.LastInsertId()
	fmt.Println(id)
}
Get All MySQL Rows in Go
by yhuang Go 
package main

import (
	"database/sql"
	"fmt"
	"log"
	"time"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}

	type user struct {
		id        int
		username  string
		password  string
		createdAt time.Time
	}

	rows, err := db.Query(`SELECT id, username, password, created_at FROM users`)
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()

	var users []user
	for rows.Next() {
		var u user

		err := rows.Scan(&u.id, &u.username, &u.password, &u.createdAt)
		if err != nil {
			log.Fatal(err)
		}
		users = append(users, u)
	}
	if err := rows.Err(); err != nil {
		log.Fatal(err)
	}

	fmt.Printf("%#v", users)
}
Query MySQL Rows in Go
by yhuang Go 
package main

import (
	"database/sql"
	"fmt"
	"log"
	"time"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}

	var (
		id        int
		username  string
		password  string
		createdAt time.Time
	)

	query := "SELECT id, username, password, created_at FROM users WHERE id = ?"
	if err := db.QueryRow(query, 1).Scan(&id, &username, &password, &createdAt); err != nil {
		log.Fatal(err)
	}

	fmt.Println(id, username, password, createdAt)
}
Delete MySQL Rows in Go
by yhuang Go 
package main

import (
	"database/sql"
	"log"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}

	_, err := db.Exec(`DELETE FROM users WHERE id = ?`, 1)
	if err != nil {
		log.Fatal(err)
	}
}
Connect to MySQL Database in Go
by yhuang Go
Obtain a database connection from code or a command line client.
package main

import (
	"database/sql"
	"log"

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

func main() {
	db, err := sql.Open("mysql", "root:root@(127.0.0.1:3306)/root?parseTime=true")
	if err != nil {
		log.Fatal(err)
	}
	if err := db.Ping(); err != nil {
		log.Fatal(err)
	}
}