What are the PHP Data Objects?

[Jacques25]

Hello friends,
I have started PHP programming language before couple of months. I have done the basic programs in PHP. Now I want to know about the data objects that are present in PHP. So thought that there would be someone over there, who might be interested in helping me. So please tell me what are the PHP Data Objects? Hope that you got my point.!! Please help me soon.!!

[Warner]

The PHP Data Objects (PDO) extension defines a lightweight interface to access a database from PHP. Each pilot database implements the PDO interface can use specific features of each database using extensions functions. You will have to keep in mind that you can not perform any function database using the PDO extension by itself, you must use a specific PDO driver to the database server to access the database. PDO provides an abstraction layer to the data access, which means that you use the same functions to issue queries and fetch data or the database used. PDO does not provide an abstraction of database: it does not rewrite SQL or emulate missing features. You should use a full-blown abstraction if you need it.

[MindSpace]

PDO ships with PHP 5.1 and is available as a PECL extension for PHP 5.0; PDO requires the new OO features in PHP 5 and therefore, does not work with earlier versions of PHP. These functions are available in the standard PHP module, which is always available. PDO and the driver PDO_SQLITE are enabled by default since PHP 5.1.0. You must enable the PDO driver for the database of your choice, see the documentation for the drivers specific to your database for more information. Note that at compile PDO as shared extension (not recommended), then all PDO drivers must be loaded after loading PDP.

[Reegan]

When installing PDO as shared module, php.ini must be updated to PDO extension loaded automatically when PHP comes into operation. You also need to enable drivers specific to your database, make sure that these drivers will be listed after the line pdo.so, as PDO must be initialized before loading the extensions specific to databases. If you compile and PDO extensions for database statically, you can skip the following step :

• extension = pdo.so

If you are using the Windows, PDO and all the major drivers ship with PHP as shared extensions, and simply need to be activated by editing the php.ini file :

• extension = php_pdo.dll

[opaper]

The following are the predefined constants :

• PDO:: PARAM_BOOL (integer) - Represents the data type boolean.
• PDO:: PARAM_NULL (integer) - Represents the data type of SQL NULL.
• PDO:: PARAM_INT (integer) - Represents the data type INTEGER SQL.
• PDO:: PARAM_STR (integer) - Represents the data types CHAR, VARCHAR, or other types of data in a SQL string.
• PDO:: PARAM_STMT (integer) - Represents a type of game results. Not currently supported by all drivers.

[kyosang]

PDO uses class constants since PHP 5.1. Older versions use global constants in the form PDO_PARAM_BOOL. The following are some more predefined constants :

• PDO:: PARAM_INPUT_OUTPUT (integer) - Specifies that the parameter is an INOUT parameter for a stored procedure. You must use the OR operator with a data type explicit PDO:: PARAM_ *.
• PDO:: FETCH_NAMED (integer) - Specifies that the fetch method shall return each row as an array indexed by column name as returned in the corresponding result set. If the result set contains multiple columns with the same name, PDO:: FETCH_NAMED returns an array of values per column name.
• PDO:: FETCH_NUM (integer) - Specifies that the fetch method shall return each row as an array indexed by column number as returned in the corresponding result set, starting at 0.
• PDO:: FETCH_OBJ (integer) - Specifies that the fetch method shall return each row as an object with property names corresponding to the column names as returned in the result set.