Go 言語でデータベース関数を学習し、PostgreSQL データの追加、削除、変更、クエリ操作を実装します。

go get github.com/lib/pq

import (
    "database/sql"
    _ "github.com/lib/pq"
)

func connectDB() (*sql.DB, error) {
    connStr := "user=postgres dbname=yourDBName password=yourPassword host=yourHost port=yourPort sslmode=require"
    db, err := sql.Open("postgres", connStr)
    if err != nil {
        return nil, err
    }
    return db, nil
}

func queryData() {
    db, err := connectDB()
    if err != nil {
        fmt.Println("连接数据库失败：", err)
        return
    }
    defer db.Close()

    rows, err := db.Query("SELECT * FROM your_table")
    if err != nil {
        fmt.Println("执行查询语句失败：", err)
        return
    }
    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err := rows.Scan(&id, &name)
        if err != nil {
            fmt.Println("读取数据失败：", err)
            return
        }
        fmt.Printf("id: %d, name: %s
", id, name)
    }
}

func insertData(id int, name string) error {
    db, err := connectDB()
    if err != nil {
        return err
    }
    defer db.Close()

    _, err = db.Exec("INSERT INTO your_table (id, name) VALUES ($1, $2)", id, name)
    if err != nil {
        return err
    }
    return nil
}

func updateData(id int, newName string) error {
    db, err := connectDB()
    if err != nil {
        return err
    }
    defer db.Close()

    _, err = db.Exec("UPDATE your_table SET name = $1 WHERE id = $2", newName, id)
    if err != nil {
        return err
    }
    return nil
}

func deleteData(id int) error {
    db, err := connectDB()
    if err != nil {
        return err
    }
    defer db.Close()

    _, err = db.Exec("DELETE FROM your_table WHERE id = $1", id)
    if err != nil {
        return err
    }
    return nil
}