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punbb13:database_helpers 2010/04/09 08:54 punbb13:database_helpers 2020/02/06 11:04 current
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Let's discuss how to use the query builder. Let's discuss how to use the query builder.
-===== Data Manipulation in query builder ====== +===== Query Builder: Data Manipulation ======
- +
-First consider the DML (Data Manipulation Language) part of the PunBB database layer class.+
==== SELECT ==== ==== SELECT ====
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$forum_db->query_build($query) or error(__FILE__, __LINE__);</code> $forum_db->query_build($query) or error(__FILE__, __LINE__);</code>
-===== Data Definition in query builder ======+===== Data Definition ======
Now let's consider the DDL (Data Definition Language) part of the PunBB database layer class. Now let's consider the DDL (Data Definition Language) part of the PunBB database layer class.
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==== Fields ==== ==== Fields ====
-FIXME+ 
 +<code php>function field_exists($table_name, $field_name, $no_prefix = false)</code> 
 + 
 +Checks if the field ''$field_name'' is present in the table ''$table_name''. 
 + 
 +<code php>function add_field($table_name, $field_name, $field_type, $allow_null, $default_value = null, $after_field = null, $no_prefix = false)</code> 
 + 
 +Adds a field to the ''$table_name'' table. One can specify the name of an existent field, ''$after_field'', to insert after it the field to be added. The meaning of the other parameters is clear from its names. 
 + 
 +<code php>function alter_field($table_name, $field_name, $field_type, $allow_null, $default_value = null, $after_field = null, $no_prefix = false)</code> 
 + 
 +Modifies the ''$field_name'' field. The meaning of parameters is the same as above. 
 + 
 +<code php>function drop_field($table_name, $field_name, $no_prefix = false)</code> 
 + 
 +Removes the ''$field_name'' field from the ''$table_name'' table. 
 + 
 +Here are examples of the fields manipulation. 
 + 
 +<code php>// Taken from admin/db_update.php 
 +$forum_db->alter_field('posts', 'poster_ip', 'VARCHAR(39)', true); 
 +$forum_db->alter_field('users', 'registration_ip', 'VARCHAR(39)', false, '0.0.0.0');</code> 
 + 
 +<code php>// Taken from the pun_pm extension 
 +// Install section 
 +if (!$forum_db->field_exists('users', 'pun_pm_new_messages')) 
 +  $forum_db->add_field('users', 'pun_pm_new_messages', 'INT(10)', true); 
 + 
 +// Uninstall section 
 +$forum_db->drop_field('users', 'pun_pm_new_messages');</code>
==== Indexes ==== ==== Indexes ====
-FIXME 
 +<code php>function index_exists($table_name, $index_name, $no_prefix = false)</code>
 +
 +Checks if the index ''$index_name'' is present in the table ''$table_name''.
 +
 +<code php>function add_index($table_name, $index_name, $index_fields, $unique = false, $no_prefix = false)</code>
 +
 +Adds an index to the ''$table_name'' table. ''$index_fields'' is the array of fields to be added to the index.
 +
 +<code php>function drop_index($table_name, $index_name, $no_prefix = false)</code>
 +
 +Removes the ''$index_name'' index from the ''$table_name'' table.
 +
 +Here are examples of the indexes manipulation.
 +
 +<code php>// Taken from admin/db_update.php
 +if (!$forum_db->index_exists('online', 'user_id_ident_idx'))
 +{
 +  ...
 +  $forum_db->add_index('online', 'user_id_ident_idx', array('user_id', 'ident'), true);
 +  ...
 +}
 +
 +$forum_db->drop_index('online', 'user_id_idx');</code>

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