In fact, there is no desire today..-MySQLi, desire..-MySQLi_PHP Tutorial

In fact, I have no desire today..-MySQLi, desire..-MySQLi

　hi

I had a refreshing swim at noon, but after finishing reading One Punch Man in the afternoon, I no longer had the desire to learn. . . Force yourself to update something and read a book later.

1. MySQLi

2. MySQLi OOP-based programming

2.1 Using parsing

--Basic

MySQLi is an extended class library, essentially a class (?).

The general process is the same as MySQL: connection, library selection, character set setting, SQL statement execution, closing connection .

--Link library example

/*
* Connect and select database
*/
$mysqli=new mysqli('localhost', 'root' , '');
print_r($mysqli);echo "
";

echo $mysqli->select_db('test');echo "
";

$mysqli2=new mysqli();
print_r($mysqli2->connect('localhost', 'root', ''));echo "
";

print_r($mysqli3=new mysqli('localhost', 'root', '','test'));echo "
";

Three different methods, the methods here are all done using the class attributes of mysqli; of course, you can also use mysqli commands to link;

$con=mysqli_connect(HOST,USERNAME,PASSWORD)

There is some information in the results

mysqli Object
	(
	[affected_rows] => 0
	[client_info] => mysqlnd 5.0.11-dev - 20120503 - $Id: bf9ad53b11c9a57efdb1057292d73b928b8c5c77 $
	[client_version] => 50011
	[connect_errno] => 0
	[connect_error] =>
	[errno] => 0
	[error] =>
	[error_list] => Array
	(
	)
	[field_count] => 0
	[host_info] => localhost via TCP/IP
	[info] =>
	[insert_id] => 0
	[server_info] => 5.6.17
	[server_version] => 50617
	[stat] => Uptime: 968 Threads: 1 Questions: 24 Slow queries: 0 Opens: 70 Flush tables: 1 Open tables: 63 Queries per second avg: 0.024
	[sqlstate] => 00000
	[protocol_version] => 10
	[thread_id] => 11
	[warning_count] => 0
	)

These attributes can be obtained through the attributes of the object, such as

echo $mysqli->client_info;echo "
";

Or it can be obtained through corresponding methods. You can see these things in the manual.

header('content-type:text/html;charset=utf-8');
//1. Establish a connection to MySQL data
// $mysqli= new mysqli('localhost','root','root');
// //print_r($mysqli);
// //2. Open the specified database
// $mysqli- >select_db('test');
// $mysqli=new mysqli();
// $mysqli->connect('127.0.0.1','root','root');
// print_r($mysqli);

//Open the specified database while establishing a connection
$mysqli=@new mysqli('localhost','root','root','test');
//print_r($mysqli);
//$mysqli->connect_errno: Get the error number generated by the connection
//$mysqli->connect_error: Get the error message generated by the connection
if($mysqli->connect_errno){
die('Connect Error:'.$mysqli->connect_error);
}
print_r($mysqli);
echo '

---

';
echo 'Client information:'.$mysqli->client_info.'
';
echo $mysqli->get_client_info().'
';
echo 'Client version:'.$mysqli->client_version.'
';
echo '

---

';
echo 'Server-side information:'.$ mysqli->server_info.'
';
echo $mysqli->get_server_info();
echo '

---

';
echo 'Server version:' .$mysqli->server_version.'
';

echo '

---

';

--Character set example

//1. Establish a connection to MySQL
$mysqli=@new mysqli('localhost','root','root','test');
if ($mysqli->connect_errno){
die('Connect Error:'.$mysqli->connect_error);
}
//2. Set the default client encoding utf8
$mysqli->set_charset('utf8');

///3. Execute SQL query
$sql=<< CREATE TABLE IF NOT EXISTS mysqli(
id TINYINT UNSIGNED AUTO_INCREMENT KEY,
username VARCHAR(20) NOT NULL
);
EOF;
$res=$mysqli->query($sql);
var_dump($res);

/*
SELECT/DESC/DESCRIBE/SHOW/EXPLAIN returns the mysqli_result object if the execution is successful, and false if the execution fails
For the execution of other SQL statements, true is returned if the execution is successful, otherwise false
*/
//Close the connection
$mysqli->close();

It should be noted that the database is utf8, not utf-8;

2.2 Insert record operation

Increase.

--connect.php

Because a series of operations to connect to the database are commonly used, for this, our simple method is to encapsulate it and call

everywhere

require_once 'connect.php';

connect.php

/*
* Connection and library selection (header) files
*/
$mysqli=new mysqli('localhost', 'root ', '','test');
if($mysqli->connect_errno){
die('Connect Error:'.$mysqli->connect_error);
}else{
echo 'Client information:'.$mysqli->client_info.'
';
}
$mysqli->set_charset('utf8');

--Added

/*
* Insert data into database
*/

require_once 'connect.php';

$sql="insert mysqli(username) value('Tom')";
echo $mysqli->query($sql);

What is executed here is a single sql statement.

Or improve it a little, add a judgment, and output error information.

if($res){
echo $mysqli->insert_id;
}else{
echo 'ERROR '.$mysqli->error;
}

Or, insert multiple records

$sql="insert mysqli(username) value('Sdaf'),('Andy')";

2.3 Update Record

Updated.

$sql="update test set id=id 10";
$mysqli->query($sql);

2.4 Delete

Delete

$sql="delete from mysqli where id>=2";

--

Special note, there are three situations returned by affected_rows:

-1 There is a problem with the sql statement;

0 No affected statements;

>=0 Number of affected items.

--Summary

header('content-type:text/html;charset=utf-8');
$mysqli=new mysqli('localhost','root','root', 'test');
if($mysqli->connect_errno){
die('CONNECT ERROR:'.$mysqli->connect_error);
}
$mysqli->set_charset ('utf8');

//Execute SQL query
//Add record
//Execute a single SQL statement, only one SQL statement can be executed
// $sql="INSERT user(username,password) VALUES(' king','king');";
// $sql.="DROP TABLE user;";
$sql="INSERT user(username,password) VALUES('queen1','queen1') ,('queen2','queen2'),('queen3','queen3'),('queen4','queen4')";
$res=$mysqli->query($sql);
if($res){
//Get the value of AUTO_INCREMENT generated by the previous insert operation
echo 'Congratulations on your successful registration, you are the '.$mysqli->insert_id.' user on the website< ;br/>';
//Get the number of affected records generated by the previous operation
echo 'There are'.$mysqli->affected_rows.' records affected';
}else{
//Get the error number and error message generated by the previous operation
echo 'ERROR '.$mysqli->errno.':'.$mysqli->error;
}
echo '

---

';

//Add age 10 in the table
$sql="UPDATE user SET age=age 10";
$res=$mysqli->query($sql);
if($res ){
echo $mysqli->affected_rows.'records updated';
}else{
echo "ERROR ".$mysqli->errno.':'.$mysqli-> error;
}
echo '

---

';

//Delete the user with id<=6 in the table
$sql="DELETE FROM user WHERE id<=6";
$res=$mysqli->query($sql);
if($res){
echo $mysqli->affected_rows.'Record deleted';
}else{
echo "ERROR ".$mysqli->errno.': '.$mysqli->error;
}
//Close the connection to MySQL
$mysqli->close();

2.5 Check

It should be noted that select is used, so the result set is returned, which is print_r or var_dump that can be printed out.

So here we will talk about the selection of the returned result set.

header('content-type:text/html;charset=utf-8');
$mysqli=new mysqli('localhost','root','root', 'test');
if($mysqli->connect_errno){
die('CONNECT ERROR:'.$mysqli->connect_error);
}
$mysqli->set_charset ('utf8');
$sql="SELECT id,username,age FROM user";
$mysqli_result=$mysqli->query($sql);
/ /var_dump($mysqli_result);
if($mysqli_result && $mysqli_result->num_rows>0){
//echo $mysqli_result->num_rows;
//$rows=$ mysqli_result->fetch_all();//Get all records in the result set, the default return is two-dimensional
//Form of index index
//$rows=$mysqli_result->fetch_all( MYSQLI_NUM);
//$rows=$mysqli_result->fetch_all(MYSQLI_ASSOC);
//$rows=$mysqli_result->fetch_all(MYSQLI_BOTH);
// $row= $mysqli_result->fetch_row();//Get a record in the result set and return it as an index array
// print_r($row);
// echo '

---

';
// $row=$mysqli_result->fetch_assoc();//Get a record in the result set and return it as an associative array
// print_r($row);
// echo '

---

';
// $row=$mysqli_result->fetch_array();//Both
// print_r($row) ;

// echo '

---

';
// $row=$mysqli_result->fetch_array(MYSQLI_ASSOC);
// print_r( $row);

// echo '

---

';
// $row=$mysqli_result->fetch_object();
// print_r($row);
// echo '

---

';
// //Move the result set internal pointer
// $mysqli_result->data_seek(0);
// $row=$mysqli_result->fetch_assoc();
// print_r($row);

// print_r($rows);

while($row=$mysqli_result->fetch_assoc()){
//print_r($row);
//echo '

---

';
$rows[ ]=$row;
}
print_r($rows);

//Release the result set
$mysqli_result->free();


}else{
echo 'Query error or no record in the result set';
}
$mysqli->close();

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