golang sqlite3 CRUD

Posted 2020-08-16 ibg

pacakge main
import (
    "database/sql"
    "fmt"
    "log"
    _ "github.com/mattn/go-sqlite3" // sqlite3 dirver
)

// People have database fields
type People struct {
    id   int
    name string
    age  int
}

type appContext struct {
    db *sql.DB
}

func connectDB(dbName string) (*appContext, string) {
    db, err := sql.Open("sqlite3", dbName)
    if err != nil {
        return nil, err.Error()
    }
    if err = db.Ping(); err != nil {
        return nil, err.Error()
    }
    return &appContext{db}, ""
}

func (c *appContext) getAllData() {
    rows, err := c.db.Query("SELECT * FROM users")
    if err != nil {
        fmt.Println(err.Error())
        return
    }
    defer rows.Close()

    for rows.Next() {
        p := new(People)
        err := rows.Scan(&p.id, &p.name, &p.age)
        if err != nil {
            fmt.Println(err)
        }
        fmt.Println(p.id, p.name, p.age)
    }
}

// ADD
func (c *appContext) Add() {
    stmt, err := c.db.Prepare("INSERT INTO users(name,age) values(?,?)")
    if err != nil {
        log.Fatal(err)
    }
    result, err := stmt.Exec("Jack", 1)
    if err != nil {
        fmt.Printf("add error: %v", err)
        return
    }
    lastID, err := result.LastInsertId()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("inserted id is ", lastID)
}

// DELETE
func (c *appContext) Delete() {
    stmt, err := c.db.Prepare("DELETE FROM users WHERE id = ?")
    if err != nil {
        log.Fatal(err)
    }
    result, err := stmt.Exec(1)
    if err != nil {
        log.Fatal(err)
    }
    affectNum, err := result.RowsAffected()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("delete affect rows is ", affectNum)
}

// UPDATE
func (c *appContext) Update() {
    stmt, err := c.db.Prepare("UPDATE users SET age = ? WHERE id = ?")
    if err != nil {
        log.Fatal(err)
    }
    result, err := stmt.Exec(10, 1)
    if err != nil {
        log.Fatal(err)
    }
    affectNum, err := result.RowsAffected()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("update affect rows is ", affectNum)
}

// sqlite3 CRUD
func main() {
    c, err := connectDB("abc.db")
    if err != "" {
        print(err)
    }

    c.getAllData()
    fmt.Println("get action done!")

    c.Add()
    fmt.Println("add action done!")

    c.Delete()
    fmt.Println("delete action done!")

    c.Update()
    fmt.Println("update action done!")
}