【PHP】mysql基本操作整合

<?php
function connetionDB($servername, $username, $password, $db) {
// 创建连接
$conn = mysqli_connect($servername, $username, $password, $db);

// 检测连接
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
return FALSE;
}
return $conn;
}

//创建数据库
function create_db($dbname, $conn) {
$sql = "create database '$dbname'";
if(mysqli_query($conn, $sql)) {
echo "DB created successfully";
}else {
echo "Error: ".mysqli_error($conn);
}
}

//新建表
function create_table($conn) {
$sql = "CREATE TABLE Account (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(30) NOT NULL,
password VARCHAR(30) NOT NULL
)";

if(mysqli_query($conn, $sql)) {
echo "table created successfully";
}else{
echo "Error: ".mysqli_error($conn);
}
}

//插入数据
function insert($username, $password, $conn){
$sql = "insert into Account (username, password) values ('$username', '$password')";
if(mysqli_query($conn, $sql)) {
echo "Insert successfully<br>";
}else{
echo "Error:" . mysqli_error($conn);
}
}

//查询数据
function get($username, $conn) {
$sql = "SELECT password FROM Account WHERE username = '$username'";
$result = mysqli_query($conn, $sql);
if (!$result) {
printf("Error: %s\n", mysqli_error($conn));
exit();
}
while($row = mysqli_fetch_array($result)) {
//        echo "username: " . $username ." password : " . $row['password'];
//        echo "<br>";
return $row['password'];
}

}

//删除数据
function delete($username, $password, $conn) {
$sql = "DELETE FROM Account WHERE username = '$username' and password = '$password'";
if(mysqli_query($conn, $sql)) {
echo "Delete $username successfully<br>";
}else{
echo "Error:" . mysqli_error($conn);
}
}

//更新数据
function update($username, $password, $new_username, $new_password, $conn) {
$sql = '';
if($new_username == '' and $new_password != '') {
$sql = "UPDATE Account SET password = '$new_password' WHERE username = '$username' AND password = '$password'";
}else if($new_username != '' and $new_password == ''){
$sql = "UPDATE Account SET username = '$new_username' WHERE username = '$username' AND password = '$password'";
}else if($new_username != '' and $new_password != ''){
$sql = "UPDATE Account SET username = '$new_username', password = '$new_password' WHERE username = '$username' AND password = '$password'";
}
if(mysqli_query($conn, $sql)) {
//        echo "Update successfully";
return true;
}else {
//        echo "Error : " . mysqli_error($conn);
return false;
}
}

//关闭连接
function closeDB($conn) {
mysqli_close($conn);
}