PHP操作MySQL数据库的常用方法

$conn=mysql_connect("localhost", "root", "123456") or die("数据库连接失败");
mysql_select_db("test") or die("选择数据库失败");;
$sql="select * from user";
$data=mysql_query($sql);
echo '

 // 从表中提取信息的sql语句
$strsql="SELECT * FROM `gbook`";
// 执行sql查询
$result=mysql_db_query($mysql_database, $strsql, $conn);
// 获取查询结果
$row=mysql_fetch_row($result);

 
echo '';
echo '

$dsn = "mysql:host=localhost;dbname=test";
$username = 'root';
$password = '123456';
$options = array(
   PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
);

$pdo = new PDO($dsn, $username, $password, $options);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
增:

方法1: 绑定关联数组

$str=$pdo->prepare("INSERT INTO `user` (`username`, `password`) VALUES (:username,:password)");
$str->execute(array(":username"=>"test", ":password"=>"passwd"));

方法2: 绑定索引数组

$str=$pdo->prepare("INSERT INTO `user` (`username`, `password`) VALUES (?,?)");
$str->execute(array("test", "passwd"));
删:

$str=$pdo->prepare("delete from user where id > 3");
$str->execute();

改:

$str=$pdo->prepare("UPDATE `user` SET username=:username,password=:password where id=:id");
$str->execute(array(":username"=>"test", ":password"=>"passwd", ":id"=>"3"));
查:
方法1: 单个取出,循环遍历,返回到数组

$str=$pdo->prepare("select * from user where id > :id  order by id");
$str->execute(array(":id"=>2));
$str->setFetchMode(PDO::FETCH_ASSOC);
//共三种:1.PDO::FETCH_BOTH(默认)  2.FETCH_ASSOC  3.FTECH_NUM
 
while($data=$str->fetch()){
print_r($data);
echo '
';
}

方法2: 全部取出,返回到二维数组

$str=$pdo->prepare("select * from user order by fid");
$str->execute();
$data=$str->fetchAll(PDO::FETCH_NUM);
print_r($data);

方法3:单个取出,循环遍历,绑定字段名到变量

$str=$pdo->prepare("select fid,username,password from user order by id");
$str->execute();
 
$str->bindColumn("id",$id);
$str->bindColumn("username",$username);
$str->bindColumn(3,$password);
 
while($str->fetch()){
echo "$id | $username | $password
";
}
echo "总记录数：".$str->rowCount()."
";
echo "总字段数：".$str->columnCount()."
";

(用mysqli链接MYSQL数据库)
requery_once("config.ini.php");
$mysqliObj = new mysqli($dbhost,$dbuser,$dbpwd,$dbname);
if(mysqli_connect_errno()){
 echo "连接失败".mysqli_connect_error();
 exit();
}
$mysqliObj->query("set name $charName");

（其他操作）
 
查询
-----------------------------------------------------
(单条查询)
$sql = "drop table  if exists user;";
$mysqliObj->query($sql);
 
(多条查询)
$musqliObj->multip_query($sql)
 
 
 
返回执行$sql受影响的行数（）
----------------------------------------------------
if($mysqliObj->query($sql))
echo $mysqliObj->affected_rows;
 
insert 插入时，返回插入的id (很有用)
---------------------------------------------------
 $num = $mysqliObj->insert_id;

$mysqli=new mysqli("localhost", "root", "123456", "test");
$sql="select * from user  order by id";
$result=$mysqli->query($sql);
echo '