How to use Go language for database operations?

With the advent of the Internet era, a large amount of data needs to be stored and managed. As an efficient data management tool, the database plays a vital role. In actual development, Go language has been widely used for database operations. This article will introduce how to use Go language for database operations.

1. Database operations in Go language

The Go language has built-in support for SQL databases, providing database/sql and database/sql/driver Package to perform database related operations. Since database/sql is a universal interface, it can work with any database driver that conforms to this interface, such as MySQL, PostgreSQL, SQLite, etc.

2. Connect to MySQL database

Before using Go language to perform database operations, we need to install the corresponding driver first.

Taking the MySQL database as an example, we can use the go get command to install the MySQL driver:

go get -u github.com/go-sql-driver/mysql

After successful installation, we can connect to the MySQL database and perform query operations:

package main

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

func main() {
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname")
    if err != nil {
        panic(err.Error())
    }
    defer db.Close()

    rows, err := db.Query("SELECT id, name FROM users")
    if err != nil {
        panic(err.Error())
    }
    defer rows.Close()

    var id int
    var name string

    for rows.Next() {
        err := rows.Scan(&id, &name)
        if err != nil {
            panic(err.Error())
        }
        fmt.Printf("ID: %d, Name: %s
", id, name)
    }
}

In the above code, we connect to the MySQL database through the sql.Open() function. The first parameter of this function is the name of the database driver, and the second parameter is the connection string.

Then, we executed a query statement through the db.Query() function, which returned a *sql.Rows type result set. Next, we loop through each row of data through rows.Next(), and then read the data into the variable through the rows.Scan() function.

3. Query statement parameterization

In actual applications, we often need to use variables as parameters of query statements. Parameterized query statements can effectively avoid SQL injection attacks and improve query efficiency.

In the Go language, we can use placeholders in the form of ? or :name to represent the parameters of the query statement. Then, before executing the query statement, we need to call the Prepare() function to preprocess the query statement and then execute the query operation.

package main

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

func main() {
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname")
    if err != nil {
        panic(err.Error())
    }
    defer db.Close()

    stmt, err := db.Prepare("SELECT id, name FROM users WHERE id = ?")
    if err != nil {
        panic(err.Error())
    }
    defer stmt.Close()

    var id int = 1

    rows, err := stmt.Query(id)
    if err != nil {
        panic(err.Error())
    }
    defer rows.Close()

    var name string

    for rows.Next() {
        err := rows.Scan(&id, &name)
        if err != nil {
            panic(err.Error())
        }
        fmt.Printf("ID: %d, Name: %s
", id, name)
    }
}

In the above code, we use the stmt.Query() function to execute the query statement with the parameter id. Note that we need to use the db.Prepare() function to preprocess query statements, which allows the database to precompile SQL statements and improve query efficiency.

4. Transaction processing

In actual applications, we usually need to perform transaction processing on the database to ensure data integrity and consistency.

In Go language, we can use the db.Begin() function to start a transaction, and then perform all database operations in the transaction. If all operations are executed successfully, we can call the tx.Commit() function to commit the transaction, otherwise we need to call the tx.Rollback() function to roll back the transaction.

package main

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

func main() {
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname")
    if err != nil {
        panic(err.Error())
    }
    defer db.Close()

    tx, err := db.Begin()
    if err != nil {
        panic(err.Error())
    }

    stmt, err := tx.Prepare("UPDATE users SET name = ? WHERE id = ?")
    if err != nil {
        panic(err.Error())
    }
    defer stmt.Close()

    _, err = stmt.Exec("Bob", 1)
    if err != nil {
        tx.Rollback()
        panic(err.Error())
    }

    _, err = stmt.Exec("Mike", 2)
    if err != nil {
        tx.Rollback()
        panic(err.Error())
    }

    err = tx.Commit()
    if err != nil {
        tx.Rollback()
        panic(err.Error())
    }

    fmt.Println("Transaction committed.")
}

In the above code, we use the db.Begin() function to start a transaction, and then use the transaction object tx to perform all database operations. After all operations are executed successfully, we call the tx.Commit() function to commit the transaction, otherwise the transaction is rolled back.

5. Summary

This article introduces how to use Go language to perform database operations, including connecting to the database, query statement parameterization, transaction processing, etc. Through the study of this article, readers can master the database operation skills of Go language and provide assistance for actual application development.

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