Original Simple use of PDO in PHP5

simple use of PDO in PHP5

Author: Heiyeluren Time: 2006-10-29
Keywords: PHP PHP5 PDO Database abstract class

PDO (PHP Data Object) is a new PHP 5 things, when PHP 6 are coming out, PHP 6 only by default use PDO to process the database, will all the database expansion to the PECL, then the default is not our favorite php_ Mysql.dll and so on, then how to pinch, we only with the times, I have a small try a PDO. (This article is only entry-level, master can skip, hehe)

"What's PDO?"

PDO is a major feature of PHP 5, because before PHP 5 php4/php3 are a bunch of database extensions to connect and process with each database, what Php_mysql.dll, Php_pgsql.dll, Php_mssql.dll, Php_ Sqlite.dll and so on to connect MySQL, PostgreSQL, MS SQL Server, SQLite, we must, by virtue of ADOdb, PEAR::D B, Phplib: Database abstract classes such as:D B to help us, extremely cumbersome and inefficient , after all, how efficient PHP code can be that we write directly with C + + to the expansion slope of high pinch. Therefore, the emergence of PDO is inevitable, we have to calm the attitude of learning to accept the use, perhaps you will find that you can reduce a lot of kung fu Oh.

"Install PDO"

I am on the Windows XP SP2, so, the whole process is in the Windows line, as for Linux/freebsd platform, please find the data setup.
I'm PHP 5.1.4, already with the Php_pdo.dll extensions, but need a little setup to use.

Open C:/windows/php.ini, that's my PHP profile, and find the following line:
Extension_dir
This is the directory where we expand, my PHP 5 extension is in: C:/php5/ext, then I will change this line to: Extension_dir = "C:/php5/ext"

And then find it below the php.ini:

; ;;;;;;;;;;;;;;;;;;;;;
; Dynamic Extensions;
; ;;;;;;;;;;;;;;;;;;;;;

Here's a bunch of similar, extension=php_mbstring.dll stuff, and here's the PHP extension load configuration, and we're going to add our PDO extensions on the last side: Extension=php_pdo.dll
Extension=php_pdo_mysql.dll
Extension=php_pdo_pgsql.dll
Extension=php_pdo_sqlite.dll
Extension=php_pdo_mssql.dll
Extension=php_pdo_odbc.dll
Extension=php_pdo_firebird.dll
; Extension=php_pdo_oci8.dll

A variety of PDO drivers, can be added to the full plus, but the back of the Php_pdo_oci8.dll, because I did not install the Oralce database, so without this, use a semicolon to annotate it. Then restart our web server, Iis/apache, my IIS, hey, table despise me, on windows, simple.
After restarting, write a phpinfo.php file in the document directory of our Web server, plus these:


?
Phpinfo ();
?>

Then open our lovely browser: Ie/firefox, my FireFox 2.0, just downloaded, very cool, not afraid of rogue software, haha.
Enter in the browser: http://localhost/phpinfo.php, if your page path is inconsistent, please enter it yourself.
The output of the content, if you can see smoothly:

Pdo
PDO Support Enabled
PDO drivers MySQL, Pgsql, SQLite, MSSQL, ODBC, Firebird
There are a variety of driver instructions behind it,
Pdo_firebird,pdo_mssql,pdo_mysql,pdo_odbc,pdo_pgsql,pdo_sqlite

Well, congratulations on your installation success, otherwise please check the above steps carefully.

"A little test of a sledgehammer."

I use MySQL 4.0.26, but I personally recommend that you use MySQL 4.1.x or MySQL 5.0.x, because those editions have a lot of interesting things worth learning. We PDO need to connect here is my MySQL 4.0, if you do not install MySQL, please install yourself. We built MySQL and added table foo to the test library, including four fields such as Id,name,gender,time.

We started constructing the first PDO application, creating a pdo.php file in the Web document directory:

? Php
$DSN = "Mysql:host=localhost;dbname=test";
$db = new PDO ($dsn, ' root ', ');
$count = $db-> exec ("INSERT into foo SET name = ' Heiyeluren ', gender= ' man ', Time=now ()");
Echo $count;
$DB = null;
?>

Don't understand what it means, let's talk about it slowly. This line:
$DSN = "Mysql:host=localhost;dbname=test";
is to construct our DSN (data source), to see the information included: the database type is MySQL, the host address is localhost, the database name is test, so a few information. The data sources in different databases are constructed differently.

$db = new PDO ($dsn, ' root ', ');
Initializes a PDO object, the constructor's arguments the first one is our data source, the second is the user connecting to the database server, and the third parameter is the password. We can not guarantee the success of the connection, we will talk about the exception later, here we think it is connected successfully.

$count = $db->exec (INSERT into foo SET name = ' Heiyeluren ', gender= ' man ', Time=now ());
Echo $count;
Call our successful PDO object to execute a query that inserts a record and uses the Pdo::exec () method to return a result that affects the record, so we output the result. Finally, you need to end the object resource:
$DB = null;

The default is not a long connection, and if you need a database long connection, you need to add a final parameter: Array (pdo::attr_persistent => true) to this:
$db = new PDO ($dsn, ' root ', ' ", Array (pdo::attr_persistent => true));

One operation is so simple, perhaps not much different from the previous, and ADODB is somewhat similar.

"Continue to understand"

If we want to extract data, then we should use the data acquisition function. (The $db used below are the objects that are already connected above)

? Php
foreach ($db-> query ("SELECT * from foo")) {
Print_r ($row);
}
?>

We can also use this method of obtaining:

? Php
$rs = $db-> Query ("SELECT * from foo");
while ($row = $rs-> fetch ()) {
Print_r ($row);
}
?>

If you want to get all the data in an array at once, you can do this:

? Php
$rs = $db-> Query ("SELECT * from foo");
$result _arr = $rs-> fetchall ();
Print_r ($result _arr);
?>

Output:

Array
(
[0] => Array
(
[ID] => 1
[0] => 1
[Name] => Heiyeluren
[1] => Heiyeluren
[Gender] => male
[2] => Male
[Time] => 2006-10-28 23:14:23
[3] => 2006-10-28 23:14:23
)
}

We look inside the records, the digital index and the associated index all have, waste resources, we only need to associate the index:

? Php
$db-> setattribute (PDO:: Attr_case, PDO:: Case_upper);
$rs = $db-> Query ("SELECT * from foo");
$rs-> Setfetchmode (PDO:: FETCH_ASSOC);
$result _arr = $rs-> fetchall ();
Print_r ($result _arr);
?>

Look at the code above, the SetAttribute () method is to set some properties, the main properties are: Pdo::attr_case, Pdo::attr_errmode, and so on, we need to set up here is Pdo::attr_case, is when we use the associated index to get the dataset, the associated index is uppercase or lowercase,