go 简单的CRUD-526互联

package main

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

/**
  id int primary key     not null,
  name           text    not null,
  age            int     not null,
  address        char(50),
  salary         real

*/

type User struct {
	id      int
	name    string
	age     int
	address int
	salary  float32
}

func main() {
	db, err := sql.Open("sqlite3", "D:\\sqlite-tools-win32-x64-202310241106\\test_db.db")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	err = db.Ping()
	if err != nil {
		log.Fatal("数据库连接失败!!!:", err)
	}
	fmt.Println("数据库连接成功")

	// 查询用户
	// 获取开始时间
	startTime := time.Now()
	users := queryUsers(db)
	fmt.Println("Users:")
	for _, user := range users {
		fmt.Printf("id: %d, name: %s, address: %d,age: %d,salary: %.2f \n ", user.id, user.name, user.address, user.age, user.salary)
	}
	endTime := time.Now()
	fmt.Println("运行时间:", endTime.Sub(startTime).Seconds())

}

func queryUsers(db *sql.DB) []User {
	rows, err := db.Query("select * from user limit 1000")
	if err != nil {
		log.Fatal(err)
	}
	var users []User
	for rows.Next() {
		var user User
		err := rows.Scan(&user.id, &user.name, &user.age, &user.address, &user.salary)
		if err != nil {
			log.Fatal(err)

		}
		users = append(users, user)
	}

	return users
}

func updateUser(db *sql.DB, user User) {
	sqlStmt := `
	UPDATE users SET name = ? WHERE id = ?;
	`
	_, err := db.Exec(sqlStmt, user.Name, user.ID)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("User updated successfully!")
}

func deleteUser(db *sql.DB, userID int) {
	sqlStmt := `
	DELETE FROM users WHERE id = ?;
	`
	_, err := db.Exec(sqlStmt, userID)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("User deleted successfully!")
}

func insertUser(db *sql.DB, user User) {
	sqlStmt := `
	INSERT INTO users (name, email) VALUES (?, ?);
	`
	_, err := db.Exec(sqlStmt, user.Name, user.Email)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("User inserted successfully!")
}