PHP's PDO

The PDO contains three predefined categories: PDO, Podstatement, and Pdoexception.

1.PDO class

The PDO class represents a connection between PHP and a database, and the PDO class has the following methods:

PDO: constructor to build a new PDO object.

BeginTransaction: Transaction begins.

Commit: Commit a transaction

ErrorCode: Returns an error code from the database.

ErrorInfo: Returns a data containing error information from the database.

EXEC: Executes an SQL statement and returns the number of rows affected

GetAttribute: Returns a database Connection property.

Lastinsertid: Returns the last row ID inserted into the database

Prepare: Prepares an SQL statement for execution and returns the union result set (pdostatement) after the statement executes.

Query: Executes an SQL statement and returns the result set

Quote: Returns a string that adds quotation marks so that it can be used in SQL

RollBack: Transaction rollback

SetAttribute: Setting a Database Connection property

2.PDOStatement class

The Pdostatement class represents a preprocessing statement and a collection of union results after the statement executes, with the method:

Bindcolumn: Binds a PHP variable to the output sequence in the result set.

Bindparam: Binding a PHP variable to a parameter in a preprocessing statement

Bindvalue: Binding a value to a parameter in a preprocessing statement

Closecursor: Closes the cursor, which is the statement that can be executed again.

ColumnCount: Returns the number of columns in the result set

ErrorCode: Returns an incorrect code name from the statement

ErrorInfo: Returns an array containing error information from the statement

Execute: Executes a preprocessing statement

Fetch: Remove a row from the result set

Fetchall: Remove an array containing all rows from the result set

Fetchcolumn: Returns the data in a column in the result set.

GetAttribute: Returns a Pdostatement property

Getcolumnmeta: Returns the structure of a column in the result set.

Nextrowset: Returns the next result set

RowCount: Returns the number of rows affected by the SQL statement execution

SetAttribute: Setting a Pdostatement property

Setfetchmodel: Sets the way to get data for pdostatement.

3.PDOException

Pdoexception is simple from writing to exception.

Using PDO Case 1:

<?PHPTry{$DSN='Mysql:host=localhost;dbname=shen';//set up a data source for PDO$db =NewPDO ($DSN,'Root','Rootroot');//Construction Method//Setting Exceptions$dbSetAttribute (pdo::attr_errmode,pdo::errmode_exception); $db->exec ("Set names UTF8"); $sql="INSERT into A2 (name) values (' asdf ')"; $db->exec ($sql);//EXECUTE Statement//using preprocessing$insert = $db->prepare ('INSERT into A2 (name) values (?)'); $insert->execute (Array ('Wang')); $insert->execute (Array ('Lisi'));
Query Results $sql='select name from A2'; $query= $dbprepare ($sql); $query-execute (); Var_dump ($query-Fetchall (PDO::FETCH_ASSOC)); }Catch(pdoexception $err) {echo $err-getMessage ();}?>

Case 2: Binding parameters and Precompilation

<? PHP Try {   $dsn='mysql:host=localhost;dbname=shen';   Set the data source for PDO   $dbh= new PDO ($DSN,'root',' Rootroot '); //

$DBH->setattribute (pdo::attr_errmode,pdo::errmode_exception);

$name ='Wang'; $sth= $dbh->prepare ('select name from A2 where name =: Name'); $sth->bindparam (': Name', $name); $sth-execute (); Var_dump ($sth-Fetchall (PDO::FETCH_ASSOC)); $sth= $dbh->prepare ('SELECT * from a2 where name =?'); $sth->bindparam (1, $name, PDO::P aram_str); $sth-execute (); Var_dump ($sth-Fetchall (PDO::FETCH_ASSOC)); }Catch(pdoexception $err) {echo $err-getMessage ();}?>

In the MySQL application, in order to prevent the total injection, it is common to use functions such as intval,addslashes to escape the value into a legitimate type in SQL, this method is more complex, and the Bindparam method using PDO becomes relatively simple, Just specify the third parameter in the function, you can convert the value to the desired type and stitch it into the original statement.

Case 3: Transaction processing

Transactions generally fall into three steps

1. Start a transaction

2. Executing SQL statements in a transaction

3. Commit the transaction to complete the transaction.

<?PHPTry{$DSN='Mysql:host=localhost;dbname=shen';//set up a data source for PDO$db =NewPDO ($DSN,'Root','Rootroot');//Construction Method$dbSetAttribute (pdo::attr_errmode,pdo::errmode_exception); $db->begintransaction ();//Start a transaction//start execution of SQL statements$db->commit ();//COMMIT TRANSACTION End   }Catch(pdoexception $err) {echo $err-getMessage ();}?>

PHP's PDO