234 lines
18 KiB
HTML
234 lines
18 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
||
|
|
<head>
|
||
|
|
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<title>Database Forge Class : CodeIgniter User Guide</title>
|
||
|
|
|
||
|
|
<style type='text/css' media='all'>@import url('../userguide.css');</style>
|
||
|
|
<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
|
||
|
|
|
||
|
|
<script type="text/javascript" src="../nav/nav.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/prototype.lite.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/moo.fx.js"></script>
|
||
|
|
<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
|
||
|
|
|
||
|
|
<meta http-equiv='expires' content='-1' />
|
||
|
|
<meta http-equiv= 'pragma' content='no-cache' />
|
||
|
|
<meta name='robots' content='all' />
|
||
|
|
<meta name='author' content='ExpressionEngine Dev Team' />
|
||
|
|
<meta name='description' content='CodeIgniter User Guide' />
|
||
|
|
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
|
||
|
|
<!-- START NAVIGATION -->
|
||
|
|
<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
|
||
|
|
<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
|
||
|
|
<div id="masthead">
|
||
|
|
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
|
||
|
|
<tr>
|
||
|
|
<td><h1>CodeIgniter User Guide Version 2.1.4</h1></td>
|
||
|
|
<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<!-- END NAVIGATION -->
|
||
|
|
|
||
|
|
|
||
|
|
<!-- START BREADCRUMB -->
|
||
|
|
<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
|
||
|
|
<tr>
|
||
|
|
<td id="breadcrumb">
|
||
|
|
<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
|
||
|
|
<a href="../index.html">User Guide Home</a> ›
|
||
|
|
<a href="index.html">Database Library</a> ›
|
||
|
|
Database Forge Class
|
||
|
|
</td>
|
||
|
|
<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="ellislab.com/codeigniter/user-guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
|
||
|
|
</tr>
|
||
|
|
</table>
|
||
|
|
<!-- END BREADCRUMB -->
|
||
|
|
|
||
|
|
|
||
|
|
<br clear="all" />
|
||
|
|
|
||
|
|
|
||
|
|
<!-- START CONTENT -->
|
||
|
|
<div id="content">
|
||
|
|
|
||
|
|
<h1>Database Forge Class</h1>
|
||
|
|
|
||
|
|
<p>The Database Forge Class contains functions that help you manage your database.</p>
|
||
|
|
|
||
|
|
<h3>Table of Contents</h3>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li><a href="#init">Initializing the Forge Class</a></li>
|
||
|
|
<li><a href="#create">Creating a Database</a></li>
|
||
|
|
<li><a href="#drop">Dropping a Database</a></li>
|
||
|
|
<li><a href="#add_field">Adding Fields</a></li>
|
||
|
|
<li><a href="#add_key">Adding Keys</a></li>
|
||
|
|
<li><a href="#create_table">Creating a Table</a></li>
|
||
|
|
<li><a href="#drop_table">Dropping a Table</a></li>
|
||
|
|
<li><a href="#rename_table">Renaming a Table</a></li>
|
||
|
|
<li><a href="#modifying_tables">Modifying a Table</a></li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
|
||
|
|
<h2><a name="init"></a>Initializing the Forge Class</h2>
|
||
|
|
|
||
|
|
<p class="important"><strong>Important:</strong> In order to initialize the Forge class, your database driver must
|
||
|
|
already be running, since the forge class relies on it.</p>
|
||
|
|
|
||
|
|
<p>Load the Forge Class as follows:</p>
|
||
|
|
|
||
|
|
<code>$this->load->dbforge()</code>
|
||
|
|
|
||
|
|
<p>Once initialized you will access the functions using the <dfn>$this->dbforge</dfn> object:</p>
|
||
|
|
|
||
|
|
<code>$this->dbforge->some_function()</code>
|
||
|
|
<h2><a name="create"></a>$this->dbforge->create_database('db_name')</h2>
|
||
|
|
|
||
|
|
<p>Permits you to create the database specified in the first parameter. Returns TRUE/FALSE based on success or failure:</p>
|
||
|
|
|
||
|
|
<code>if ($this->dbforge->create_database('my_db'))<br />
|
||
|
|
{<br />
|
||
|
|
echo 'Database created!';<br />
|
||
|
|
}</code>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<h2><a name="drop"></a>$this->dbforge->drop_database('db_name')</h2>
|
||
|
|
|
||
|
|
<p>Permits you to drop the database specified in the first parameter. Returns TRUE/FALSE based on success or failure:</p>
|
||
|
|
|
||
|
|
<code>if ($this->dbforge->drop_database('my_db'))<br />
|
||
|
|
{<br />
|
||
|
|
echo 'Database deleted!';<br />
|
||
|
|
}</code>
|
||
|
|
|
||
|
|
|
||
|
|
<h1>Creating and Dropping Tables</h1>
|
||
|
|
<p>There are several things you may wish to do when creating tables. Add fields, add keys to the table, alter columns. CodeIgniter provides a mechanism for this.</p>
|
||
|
|
<h2><a name="add_field" id="add_field"></a>Adding fields</h2>
|
||
|
|
<p>Fields are created via an associative array. Within the array you must include a 'type' key that relates to the datatype of the field. For example, INT, VARCHAR, TEXT, etc. Many datatypes (for example VARCHAR) also require a 'constraint' key.</p>
|
||
|
|
<p><code>$fields = array(<br />
|
||
|
|
'users' => array(<br />
|
||
|
|
'type' => 'VARCHAR',<br />
|
||
|
|
'constraint' => '100',<br />
|
||
|
|
),<br />
|
||
|
|
);<br />
|
||
|
|
<br />
|
||
|
|
// will translate to "users VARCHAR(100)" when the field is added.</code></p>
|
||
|
|
<p>Additionally, the following key/values can be used:</p>
|
||
|
|
<ul>
|
||
|
|
<li>unsigned/true : to generate "UNSIGNED" in the field definition.</li>
|
||
|
|
<li>default/value : to generate a default value in the field definition.</li>
|
||
|
|
<li>null/true : to generate "NULL" in the field definition. Without this, the field will default to "NOT NULL".</li>
|
||
|
|
<li>auto_increment/true : generates an auto_increment flag on the field. Note that the field type must be a type that supports this, such as integer.</li>
|
||
|
|
</ul>
|
||
|
|
<p><code>$fields = array(<br />
|
||
|
|
'blog_id' => array(<br />
|
||
|
|
'type' => 'INT',<br />
|
||
|
|
'constraint' => 5, <br />
|
||
|
|
'unsigned' => TRUE,<br />
|
||
|
|
'auto_increment' => TRUE<br />
|
||
|
|
),<br />
|
||
|
|
'blog_title' => array(<br />
|
||
|
|
'type' => 'VARCHAR',<br />
|
||
|
|
'constraint' => '100',<br />
|
||
|
|
),<br />
|
||
|
|
'blog_author' => array(<br />
|
||
|
|
'type' =>'VARCHAR',<br />
|
||
|
|
'constraint' => '100',<br />
|
||
|
|
'default' => 'King of Town',<br />
|
||
|
|
),<br />
|
||
|
|
'blog_description' => array(<br />
|
||
|
|
'type' => 'TEXT',<br />
|
||
|
|
'null' => TRUE,<br />
|
||
|
|
),<br />
|
||
|
|
);<br />
|
||
|
|
</code></p>
|
||
|
|
<p>After the fields have been defined, they can be added using <dfn>$this->dbforge->add_field($fields);</dfn> followed by a call to the <dfn>create_table()</dfn> function.</p>
|
||
|
|
<h3>$this->dbforge->add_field()</h3>
|
||
|
|
<p>The add fields function will accept the above array.</p>
|
||
|
|
<h3>Passing strings as fields</h3>
|
||
|
|
<p>If you know exactly how you want a field to be created, you can pass the string into the field definitions with add_field()</p>
|
||
|
|
<p><code>$this->dbforge->add_field("label varchar(100) NOT NULL DEFAULT 'default label'");</code></p>
|
||
|
|
<p class="important">Note: Multiple calls to <dfn>add_field()</dfn> are cumulative.</p>
|
||
|
|
<h3>Creating an id field</h3>
|
||
|
|
<p>There is a special exception for creating id fields. A field with type id will automatically be assinged as an INT(9) auto_incrementing Primary Key.</p>
|
||
|
|
<p><code>$this->dbforge->add_field('id');<br />
|
||
|
|
// gives id INT(9) NOT NULL AUTO_INCREMENT</code></p>
|
||
|
|
<h2><a name="add_key" id="add_key"></a>Adding Keys</h2>
|
||
|
|
<p>Generally speaking, you'll want your table to have Keys. This is accomplished with <dfn>$this->dbforge->add_key('field')</dfn>. An optional second parameter set to TRUE will make it a primary key. Note that <dfn>add_key()</dfn> must be followed by a call to <dfn>create_table()</dfn>.</p>
|
||
|
|
<p>Multiple column non-primary keys must be sent as an array. Sample output below is for MySQL.</p>
|
||
|
|
<p><code>$this->dbforge->add_key('blog_id', TRUE);<br />
|
||
|
|
// gives PRIMARY KEY `blog_id` (`blog_id`)<br />
|
||
|
|
<br />
|
||
|
|
$this->dbforge->add_key('blog_id', TRUE);<br />
|
||
|
|
$this->dbforge->add_key('site_id', TRUE);<br />
|
||
|
|
// gives PRIMARY KEY `blog_id_site_id` (`blog_id`, `site_id`)<br />
|
||
|
|
<br />
|
||
|
|
$this->dbforge->add_key('blog_name');<br />
|
||
|
|
// gives KEY `blog_name` (`blog_name`)<br />
|
||
|
|
<br />
|
||
|
|
$this->dbforge->add_key(array('blog_name', 'blog_label'));<br />
|
||
|
|
// gives KEY `blog_name_blog_label` (`blog_name`, `blog_label`)</code></p>
|
||
|
|
<h2><a name="create_table" id="create_table"></a>Creating a table</h2>
|
||
|
|
<p>After fields and keys have been declared, you can create a new table with</p>
|
||
|
|
<p><code>$this->dbforge->create_table('table_name');<br />
|
||
|
|
// gives CREATE TABLE table_name</code></p>
|
||
|
|
<p>An optional second parameter set to TRUE adds an "IF NOT EXISTS" clause into the definition</p>
|
||
|
|
<p><code>$this->dbforge->create_table('table_name', TRUE);<br />
|
||
|
|
// gives CREATE TABLE IF NOT EXISTS table_name</code></p>
|
||
|
|
<h2><a name="drop_table" id="drop_table"></a>Dropping a table</h2>
|
||
|
|
<p>Executes a DROP TABLE sql</p>
|
||
|
|
<p><code>$this->dbforge->drop_table('table_name');<br />
|
||
|
|
// gives DROP TABLE IF EXISTS table_name</code></p>
|
||
|
|
<h2><a name="rename_table" id="rename_table"></a>Renaming a table</h2>
|
||
|
|
<p>Executes a TABLE rename</p>
|
||
|
|
<p><code>$this->dbforge->rename_table('old_table_name', 'new_table_name');<br />
|
||
|
|
// gives ALTER TABLE old_table_name RENAME TO new_table_name</code></p>
|
||
|
|
<h1><a name="modifying_tables" id="modifying_tables"></a>Modifying Tables</h1>
|
||
|
|
<h2>$this->dbforge->add_column()</h2>
|
||
|
|
<p>The add_column() function is used to modify an existing table. It accepts the same field array as above, and can be used for an unlimited number of additional fields.</p>
|
||
|
|
<p><code>$fields = array(<br />
|
||
|
|
'preferences' => array('type' => 'TEXT')<br />
|
||
|
|
);<br />
|
||
|
|
$this->dbforge->add_column('table_name', $fields);<br />
|
||
|
|
<br />
|
||
|
|
// gives ALTER TABLE table_name ADD preferences TEXT</code></p>
|
||
|
|
<h2>$this->dbforge->drop_column()</h2>
|
||
|
|
<p>Used to remove a column from a table. </p>
|
||
|
|
<p><code>$this->dbforge->drop_column('table_name', 'column_to_drop');</code></p>
|
||
|
|
<h2>$this->dbforge->modify_column()</h2>
|
||
|
|
<p>The usage of this function is identical to add_column(), except it alters an existing column rather than adding a new one. In order to change the name you can add a "name" key into the field defining array.</p>
|
||
|
|
<p><code>$fields = array(<br />
|
||
|
|
'old_name' => array(<br />
|
||
|
|
'name' => 'new_name',<br />
|
||
|
|
'type' => 'TEXT',<br />
|
||
|
|
),<br />
|
||
|
|
);<br />
|
||
|
|
$this->dbforge->modify_column('table_name', $fields);<br />
|
||
|
|
<br />
|
||
|
|
// gives ALTER TABLE table_name CHANGE old_name new_name TEXT </code></p>
|
||
|
|
<p> </p>
|
||
|
|
</div>
|
||
|
|
<!-- END CONTENT -->
|
||
|
|
|
||
|
|
|
||
|
|
<div id="footer">
|
||
|
|
<p>
|
||
|
|
Previous Topic: <a href="caching.html">DB Caching Class</a>
|
||
|
|
·
|
||
|
|
<a href="#top">Top of Page</a> ·
|
||
|
|
<a href="../index.html">User Guide Home</a> ·
|
||
|
|
Next Topic: <a href="utilities.html">Database Utilities Class</a><a href="../libraries/email.html"></a></p>
|
||
|
|
<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|