function connect(){
static $conn;
if(!$conn){
$conn = mysqli_connect(DB_HOST,DB_USER,DB_PWD) ;
}
if (mysqli_connect_errno($conn))
{
echo "连接 MySQL 失败: " . mysqli_connect_error();
}
mysqli_set_charset($conn,DB_CHARSET);
mysqli_select_db($conn,DB_DBNAME) or die("指定数据库打开失败");
/* //测试查询数据库
$sql="select category_id,category_name from category";
//$sql = "SELECT * FROM admin";
$result = mysqli_query($conn, $sql);
//返回所有的数据集
//var_dump(mysqli_fetch_all($result));die;
//处理返回的数据集
$data = [];
while($row = mysqli_fetch_assoc($result)) {
//mysqli_fetch_array
$data[] = $row;
}
//在页面上打印
var_dump($data);*/
return $conn;
}
/* 调用 */
function fetchAll($sql,$result_type=MYSQLI_ASSOC){
$conn=connect();
$result=mysqli_query($conn,$sql);
while(@$row=mysqli_fetch_array($result,$result_type)){
$rows[]=$row;
}
return $rows;
}