diff options
Diffstat (limited to 'user_guide_src/source/database/forge.rst')
| -rw-r--r-- | user_guide_src/source/database/forge.rst | 61 |
1 files changed, 41 insertions, 20 deletions
diff --git a/user_guide_src/source/database/forge.rst b/user_guide_src/source/database/forge.rst index bf17e2918..ca904ed00 100644 --- a/user_guide_src/source/database/forge.rst +++ b/user_guide_src/source/database/forge.rst @@ -2,7 +2,7 @@ Database Forge Class #################### -The Database Forge Class contains functions that help you manage your +The Database Forge Class contains methods that help you manage your database. .. contents:: Table of Contents @@ -18,13 +18,25 @@ Load the Forge Class as follows:: $this->load->dbforge() -Once initialized you will access the functions using the $this->dbforge +You can also pass another database object to the DB Forge loader, in case +the database you want to manage isn't the default one:: + + $this->myforge = $this->load->dbforge($this->other_db, TRUE); + +In the above example, we're passing a custom database object as the first +parameter and then tell it to return the dbforge object, instead of +assigning it directly to ``$this->dbforge``. + +.. note:: Both of the parameters can be used individually, just pass an empty + value as the first one if you wish to skip it. + +Once initialized you will access the methods using the ``$this->dbforge`` object:: - $this->dbforge->some_function() + $this->dbforge->some_method(); $this->dbforge->create_database('db_name') -============================================ +========================================== Permits you to create the database specified in the first parameter. Returns TRUE/FALSE based on success or failure:: @@ -108,13 +120,13 @@ Additionally, the following key/values can be used: After the fields have been defined, they can be added using -$this->dbforge->add_field($fields); followed by a call to the -create_table() function. +``$this->dbforge->add_field($fields);`` followed by a call to the +``create_table()`` method. $this->dbforge->add_field() ----------------------------- +--------------------------- -The add fields function will accept the above array. +The add fields method will accept the above array. Passing strings as fields ------------------------- @@ -193,13 +205,15 @@ into the definition Dropping a table ================ -Executes a DROP TABLE sql +Execute a DROP TABLE statement and optionally add an IF EXISTS clause. :: + // Produces: DROP TABLE table_name $this->dbforge->drop_table('table_name'); - // gives DROP TABLE IF EXISTS table_name + // Produces: DROP TABLE IF EXISTS table_name + $this->dbforge->drop_table('table_name'); Renaming a table ================ @@ -217,9 +231,9 @@ Modifying Tables **************** $this->dbforge->add_column() -============================= +============================ -The add_column() function is used to modify an existing table. It +The ``add_column()`` method 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. @@ -229,18 +243,25 @@ number of additional fields. 'preferences' => array('type' => 'TEXT') ); $this->dbforge->add_column('table_name', $fields); - // gives ALTER TABLE table_name ADD preferences TEXT + // Executes: 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. +If you are using MySQL or CUBIRD, then you can take advantage of their +AFTER and FIRST clauses to position the new column. -:: +Examples:: - $this->dbforge->add_column('table_name', $fields, 'after_field'); + // Will place the new column after the `another_field` column: + $fields = array( + 'preferences' => array('type' => 'TEXT', 'after' => 'another_field') + ); + // Will place the new column at the start of the table definition: + $fields = array( + 'preferences' => array('type' => 'TEXT', 'first' => TRUE) + ); $this->dbforge->drop_column() -============================== +============================= Used to remove a column from a table. @@ -250,9 +271,9 @@ Used to remove a column from a table. $this->dbforge->modify_column() -================================ +=============================== -The usage of this function is identical to add_column(), except it +The usage of this method 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. |