First introduction to PHP (4) PDO object configuration and use, first introduction to pdo_PHP tutorial

First introduction to PHP (4) PDO object configuration and use, first introduction to pdo

1. The concept of PDO

PDO is actually an abstraction layer of a database. Using PDO programming can easily change the database at any time in subsequent actual operations without changing the source code. The location of PDO is as shown below:

phptest","root","123");

This completes the initialization of the PDO object. The connected database is the phptest database of the mysql database. The username and password used are root and 123 respectively

If you write dsn information into the configuration file, use the following method:

$pdo = new PDO("uri:MysqlDbo.ini","root","123"); \dsn data is written in the MysqlDbo.ini file

　

　3.2 Use of PDO objects

The member methods of PDO are as follows:

　1) query($sql); //Used to execute query SQL statements. Return PDOStatement object

　2) exec($sql); //Used to perform add, delete, and modify operations and return the number of affected rows;

　3) setAttribute(); //Set a "database connection object" attribute.                                                       

　4) fetchAll(); //Parse data

The following is an example:

The original data of the database is as follows:

　

1 php 2 //Connect to database 3 try { 4 $pdo = new PDO("mysql:host=localhost;dbname=phptest", "root", "20125202" ); 5 } 6 catch (PDOException $e){ 7 die("Database connection failed".$e->getMessage()); 8 } 9 //Query statement 10 $sql = 'select * from students'; 11 //Execute statements and parse data 12 echo 'id　'.'____________'.'name'.'____________'.'sex'."
"; 13 foreach ($pdo->query($sql) as $val){ 14 echo $val['id'].'____________'.$val['name'].' ____________'.$val['sex']."
"; 15 } 16 ?>

The effect is as shown below:

1 php 2 //Connect to database 3 try { 4 $pdo = new PDO("mysql:host=localhost;dbname=phptest", "root", "123" ); 5 } 6 catch (PDOException $e){ 7 die("Database connection failed".$e->getMessage()); 8 } 9 //Insert statement 10 $sql = "insert into students values('20125203','tony','female')"; 11 //Execute statements and parse data 12 $res = $pdo->exec($sql); 13 if ($res){ 14 echo "Insertion successful!"; 15 } 16 //Query results 17 $sql = 'select * from students'; 18 echo 'id　'.'____________'.'name'.'____________'.'sex'."
"; 19 foreach ($pdo->query($sql) as $val){ 20 echo $val['id'].'____________'.$val['name'].' ____________'.$val['sex']."
"; 21 } 22 ?> The effect is as shown below:

1 php 2 //Connect to database 3 try { 4 $pdo = new PDO("mysql:host=localhost;dbname=phptest", "root", "123" ); 5 } 6 catch (PDOException $e){ 7 die("Database connection failed".$e->getMessage()); 8 } 9 //Insert statement 10 //$sql = "insert into students values('20125203','tony','female')"; 11 //Modify the statement 12 $sql = "update students set sex='male' where id='20125203'"; 13 //Execute statements and parse data 14 $res = $pdo->exec($sql); 15 if ($res){ 16 echo "Modification successful!"; 17 } 18 //Query results 19 $sql = 'select * from students'; 20 echo ' id　'.'____________'.'name'.'____________'.'sex'."
"; 21 foreach ($pdo->query($sql) as $val){ 22 echo $val['id'].'____________'.$val['name'].' ____________'.$val['sex']."
"; 23 } 24 ?> Modify data

The effect is as shown below:

1 php 2 //Connect to database 3 try { 4 $pdo = new PDO("mysql:host=localhost;dbname=phptest", "root", "20125202" ); 5 } 6 catch (PDOException $e){ 7 die("Database connection failed".$e->getMessage()); 8 } 9 //Insert statement 10 //$sql = "insert into students values('20125203','tony','female')"; 11 //Modify the statement 12 //$sql = "update students set sex='male' where id='20125203'"; 13 //Delete statement 14 $sql = "delete from students where id='20125203'"; 15 //Execute statements and parse data 16 $res = $pdo->exec($sql); 17 if ($res){ 18 echo "Delete successfully!"; 19 } 20 //Query results 21 $sql = 'select * from students'; 22 echo 'id　'.'____________'.'name'.'____________'.'sex'."
"; 23 foreach ($pdo->query($sql) as $val){ 24 echo $val['id'].'____________'.$val['name'].' ____________'.$val['sex']."
"; 25 } 26 ?> Delete data

The effect is as shown below:

The above is the basic usage of PDO and operations such as adding, deleting, checking and modifying.

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