How to connect to remote database using Golang?

Through the Go standard library database/sql package, you can connect to remote databases such as MySQL, PostgreSQL or SQLite: Create a connection string containing database connection information. Use the sql.Open() function to open a database connection. Perform database operations such as SQL queries and insert operations. Use defer to close the database connection to release resources.

How to connect to a remote database using Golang

Golang is a powerful programming language that can easily connect to a remote database. This tutorial will introduce how to use the Go standard library database/sql package to connect to remote databases such as MySQL, PostgreSQL and SQLite.

Requirements

• Golang 1.16 or higher
• Remote database (such as MySQL, PostgreSQL or SQLite)

Connection String

First we need to create a connection string that contains the information needed to connect to the database. Here's how to create connection strings for different databases:

MySQL:

"user:password@tcp(host:port)/dbname"

PostgreSQL:

"user=username password=password host=address port=port dbname=database"

SQLite:

"path/to/sqlite.db"

Among them, user, password, host, port and dbname is database specific.

Connect to the database

Use the database/sql package to connect to the database:

import (
    "database/sql"
    _ "github.com/go-sql-driver/mysql" // Import MySQL driver
    _ "github.com/lib/pq" // Import PostgreSQL driver
    _ "github.com/mattn/go-sqlite3" // Import SQLite driver
)

func main() {
    // Create a connection string
    connStr := "user:password@tcp(host:port)/dbname"

    // Open the database connection
    db, err := sql.Open("mysql", connStr)
    if err != nil {
        panic(err)
    }
    defer db.Close()  // Close the connection when the function returns
}

Practical case

The following is a database using MySQL Simple example of:

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql" // Import MySQL driver
)

func main() {
    // Connect to the database
    db, err := sql.Open("mysql", "root:@/test")
    if err != nil {
        panic(err)
    }
    defer db.Close() // Close the connection when the function returns

    // Create a table
    query := `CREATE TABLE IF NOT EXISTS users (
        id INT PRIMARY KEY AUTO_INCREMENT,
        username VARCHAR(255) NOT NULL,
        password VARCHAR(255) NOT NULL
    );`
    _, err = db.Exec(query)
    if err != nil {
        panic(err)
    }

    // Insert a record into the table
    query = `INSERT INTO users (username, password) VALUES (?, ?)`
    stmt, err := db.Prepare(query)
    if err != nil {
        panic(err)
    }
    _, err = stmt.Exec("admin", "password")
    if err != nil {
        panic(err)
    }

    // Retrieve the record from the table
    query = `SELECT * FROM users WHERE id = ?`
    var id int
    var username string
    var password string
    err = db.QueryRow(query, 1).Scan(&id, &username, &password)
    if err != nil {
        panic(err)
    }
    fmt.Println("ID:", id, "Username:", username, "Password:", password)
}

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