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+####################
+Database Forge Class
+####################
+
+The Database Forge Class contains functions that help you manage your
+database.
+
+.. contents:: Table of Contents
+
+****************************
+Initializing the Forge Class
+****************************
+
+.. important:: In order to initialize the Forge class, your database
+	driver must already be running, since the forge class relies on it.
+
+Load the Forge Class as follows::
+
+	$this->load->dbforge()
+
+Once initialized you will access the functions using the $this->dbforge
+object::
+
+	$this->dbforge->some_function()
+
+$this->dbforge->create_database('db_name')
+============================================
+
+Permits you to create the database specified in the first parameter.
+Returns TRUE/FALSE based on success or failure::
+
+	if ($this->dbforge->create_database('my_db'))
+	{
+		echo 'Database created!';
+	}
+
+$this->dbforge->drop_database('db_name')
+==========================================
+
+Permits you to drop the database specified in the first parameter.
+Returns TRUE/FALSE based on success or failure::
+
+	if ($this->dbforge->drop_database('my_db'))
+	{
+		echo 'Database deleted!';
+	}
+
+****************************
+Creating and Dropping Tables
+****************************
+
+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.
+
+Adding fields
+=============
+
+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.
+
+::
+
+	$fields = array(
+		'users' => array(
+			'type' => 'VARCHAR',
+			'constraint' => '100',
+		),
+	);
+	// will translate to "users VARCHAR(100)" when the field is added.
+
+
+Additionally, the following key/values can be used:
+
+-  unsigned/true : to generate "UNSIGNED" in the field definition.
+-  default/value : to generate a default value in the field definition.
+-  null/true : to generate "NULL" in the field definition. Without this,
+   the field will default to "NOT NULL".
+-  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.
+
+::
+
+	$fields = array(
+		'blog_id' => array(
+			'type' => 'INT',
+			'constraint' => 5,
+			'unsigned' => TRUE,
+			'auto_increment' => TRUE
+		),
+		'blog_title' => array(
+			'type' => 'VARCHAR',
+			'constraint' => '100',
+		),
+		'blog_author' => array(
+			'type' =>'VARCHAR',
+			'constraint' => '100',
+			'default' => 'King of Town',
+		),
+		'blog_description' => array(
+			'type' => 'TEXT',
+			'null' => TRUE,
+		),
+	);
+
+
+After the fields have been defined, they can be added using
+$this->dbforge->add_field($fields); followed by a call to the
+create_table() function.
+
+$this->dbforge->add_field()
+----------------------------
+
+The add fields function will accept the above array.
+
+Passing strings as fields
+-------------------------
+
+If you know exactly how you want a field to be created, you can pass the
+string into the field definitions with add_field()
+
+::
+
+	$this->dbforge->add_field("label varchar(100) NOT NULL DEFAULT 'default label'");
+
+
+.. note:: Multiple calls to add_field() are cumulative.
+
+Creating an id field
+--------------------
+
+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.
+
+::
+
+	$this->dbforge->add_field('id');
+	// gives id INT(9) NOT NULL AUTO_INCREMENT
+
+
+Adding Keys
+===========
+
+Generally speaking, you'll want your table to have Keys. This is
+accomplished with $this->dbforge->add_key('field'). An optional second
+parameter set to TRUE will make it a primary key. Note that add_key()
+must be followed by a call to create_table().
+
+Multiple column non-primary keys must be sent as an array. Sample output
+below is for MySQL.
+
+::
+
+	$this->dbforge->add_key('blog_id', TRUE);
+	// gives PRIMARY KEY `blog_id` (`blog_id`)
+	
+	$this->dbforge->add_key('blog_id', TRUE);
+	$this->dbforge->add_key('site_id', TRUE);
+	// gives PRIMARY KEY `blog_id_site_id` (`blog_id`, `site_id`)
+	
+	$this->dbforge->add_key('blog_name');
+	// gives KEY `blog_name` (`blog_name`)
+	
+	$this->dbforge->add_key(array('blog_name', 'blog_label'));
+	// gives KEY `blog_name_blog_label` (`blog_name`, `blog_label`)
+
+
+Creating a table
+================
+
+After fields and keys have been declared, you can create a new table
+with
+
+::
+
+	$this->dbforge->create_table('table_name');
+	// gives CREATE TABLE table_name
+
+
+An optional second parameter set to TRUE adds an "IF NOT EXISTS" clause
+into the definition
+
+::
+
+	$this->dbforge->create_table('table_name', TRUE);
+	// gives CREATE TABLE IF NOT EXISTS table_name
+
+
+Dropping a table
+================
+
+Executes a DROP TABLE sql
+
+::
+
+	$this->dbforge->drop_table('table_name');
+	// gives DROP TABLE IF EXISTS  table_name
+
+
+Renaming a table
+================
+
+Executes a TABLE rename
+
+::
+
+	$this->dbforge->rename_table('old_table_name', 'new_table_name');
+	// gives ALTER TABLE old_table_name RENAME TO new_table_name
+
+
+****************
+Modifying Tables
+****************
+
+$this->dbforge->add_column()
+=============================
+
+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.
+
+::
+
+	$fields = array(
+		'preferences' => array('type' => 'TEXT')
+	);
+	$this->dbforge->add_column('table_name', $fields); 
+	// gives ALTER TABLE table_name ADD preferences TEXT
+
+An optional third parameter can be used to specify which existing column
+to add the new column after.
+
+::
+
+	$this->dbforge->add_column('table_name', $fields, 'after_field');
+
+
+$this->dbforge->drop_column()
+==============================
+
+Used to remove a column from a table.
+
+::
+
+	$this->dbforge->drop_column('table_name', 'column_to_drop');
+
+
+$this->dbforge->modify_column()
+================================
+
+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.
+
+::
+
+	$fields = array(
+		'old_name' => array(
+			'name' => 'new_name',
+			'type' => 'TEXT',
+		),
+	);
+	$this->dbforge->modify_column('table_name', $fields);
+	// gives ALTER TABLE table_name CHANGE old_name new_name TEXT
+\ No newline at end of file