MySQL CRUD Function in Go Language

go-mysql-crud.go

package main

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

var MYSQL_IP = "localhost"
var MYSQL_PORT = "3306"

var MYSQL_USER = "admin"
var MYSQL_PW = "123"

var DB_NAME = "testdb"
var TABLE_NAME = "testtable"

type data struct {
    id string
    name string
}

func Create() {

    db := connect()

    _, err := db.Exec("CREATE TABLE " + TABLE_NAME + " (id VARCHAR(10), name VARCHAR(10))")
    if err != nil {
        panic(err.Error())
    }

    db.Close()
}

func Drop() {

    db := connect()

    _, err := db.Exec("DROP TABLE " + TABLE_NAME)
    if err != nil {
        panic(err.Error())
    }

    db.Close()
}

func Insert(_data data) {

    db := connect()

    stmt, err := db.Prepare("INSERT INTO " + TABLE_NAME + " VALUES (?, ?)")
    if err != nil {
        panic(err.Error())
    }
    defer stmt.Close()

    _, err = stmt.Exec(_data.id, _data.name)
    if err != nil {
        panic(err.Error())
    }

    db.Close()
}

func Query(where string, what string) *sql.Rows {

    db := connect()

    rows, err := db.Query("SELECT id, name FROM " + TABLE_NAME + " WHERE " + where + " = ?", what)
    if err != nil {
        panic(err.Error())
    }

    db.Close()

    return rows
}

func QueryAll() *sql.Rows {

    db := connect()

    rows, err := db.Query("SELECT * FROM " + TABLE_NAME)
    if err != nil {
        panic(err.Error())
    }

    db.Close()

    return rows
}

/*
func Update(where string, what string, _data data) {

    db := connect()

    stmt, err := db.Prepare("UPDATE " + TABLE_NAME + " SET " + ... + " WHERE " + where + " =?")
    if err != nil {
        panic(err.Error())
    }
    defer stmt.Close()

    _, err = stmt.Exec( ... , what)
    if err != nil {
        panic(err.Error())
    }

    db.Close()
}
*/

func Delete(where string, what string) {

    db := connect()

    stmt, err := db.Prepare("DELETE FROM " + TABLE_NAME + " WHERE " + where + " =?")
    if err != nil {
        panic(err.Error())
    }
    defer stmt.Close()

    _, err = stmt.Exec(what)
    if err != nil {
        panic(err.Error())
    }

    db.Close()
}

func connect() *sql.DB {

    db, err := sql.Open("mysql", MYSQL_USER + ":" + MYSQL_PW + "@tcp(" + MYSQL_IP + ":" + MYSQL_PORT + ")/" + DB_NAME)
    if err != nil {
        panic(err.Error())
    }

    return db
}

func printRows(rows *sql.Rows) {

    var _data data

    for rows.Next() {
        err := rows.Scan(&_data.id, &_data.name)
        if err != nil {
            panic(err.Error())
        }
        fmt.Println(_data.id, _data.name)
    }

    err := rows.Err()
    if err != nil {
        panic(err.Error())
    }
}

func main() {

    Create()

    Insert(data{"1", "kim"})
    Insert(data{"2", "lee"})
    Insert(data{"3", "park"})
    Insert(data{"4", "choi"})

    rows := Query("id", "2")
    printRows(rows)

    fmt.Println("-----")

    rows = QueryAll()
    printRows(rows)

    Delete("name", "choi")

    Drop()
}