Php uses pdo to connect to and query the SQL database

This article describes how to use pdo to connect to and query SQL databases in php. Examples of commonly used pdo connection methods and improvement methods are analyzed, and the pdo technology is analyzed and explained, for more information about how to use pdo to connect to and query SQL databases, see the example in this article. Share it with you for your reference.

The specific implementation code is as follows:

The code is as follows:

$ Login = "root ";
$ Passwd = "mysql ";
Try {
$ Db = new pdo ('MySQL: host = localhost; dbname = mysql', $ login, $ passwd );
Foreach ($ db-> query ('select * from test') as $ row ){
Print_r ($ row );
}
$ Db = null;
} Catch (pdoexception $ e ){
Echo $ e-> getmessage ();
}

Let's look at a more advanced one:

The code is as follows:

$ Dbms = 'mysql'; // Database type: oracle uses odi. for developers, if they use different databases, they do not need to remember so many functions.
$ Host = 'localhost'; // database host name
$ Dbname = 'test'; // database used
$ User = 'root'; // database connection username
$ Pass = ''; // password
$ Dsn = "$ dbms: host = $ host; dbname = $ dbname ";
Class db extends pdo {
Public function _ construct (){
Try {
Parent: :__ construct ("$ globals [dsn]", $ globals ['user'], $ globals ['pass']);
} Catch (pdoexception $ e ){
Die ("error:". $ e->__ tostring ()."
");
}
}
Public final function query ($ SQL ){
Try {
Return parent: query ($ this-> setstring ($ SQL ));
} Catch (pdoexception $ e ){
Die ("error:". $ e->__ tostring ()."
");
}
}
Private final function setstring ($ SQL ){
Echo "I want to handle $ SQL ";
Return $ SQL ;}}
$ Db = new db ();
$ Db-> setattribute (pdo: attr_case, pdo: case_upper );
Foreach ($ db-> query ('select * from xxxx_menu ') as $ row ){
Print_r ($ row );
}
$ Db-> exec ('delete from 'xxxx _ menu 'where mid = 43 ');

About pdo

The pod (php data object) extension is added to php5. by default, pdo is identified in php6 to connect to the database. all non-pdo extensions will be removed from the extension in php6. This extension provides php built-in pdo class for accessing the database. different databases use the same method name to solve the problem of inconsistent database connections.

I configured it for development in windows.

Pdo goals:

A lightweight, clear, and convenient api is provided to unify the common features of different rdbms databases, but more advanced features are not excluded, php scripts provide optional abstract/compatibility.

Pdo features:

Performance: From the very beginning, pdo learned from the success and failure of existing database expansion. because the pdo code is brand new, we have the opportunity to design performance again, take advantage of the latest features of php 5.

Capability

Pdo is designed to provide common database functions as the basis, while providing convenient access to the unique functions of rdbms.

Simple

Pdo is designed to make it easy for you to use the database. APIs do not forcibly intervene in your code and clearly indicate the process of calling each function.

Runtime scalability

Pdo extensions are modular, allowing you to load drivers to the backend of your database at runtime without re-compiling or re-installing the entire php program, for example, pdo_oci extension will replace pdo extension to implement oracle database APIs. There are also some drivers for mysql, postgresql, odbc and firebird. more drivers are still under development.

I hope this article will help you design php database programs.