Extension:CheckUser/cu useragent clienthints map table

A table for the CheckUser extension used to store the relationship between client hint rows in cu_useragent_clienthints table and one of cu_changes , cu_log_event , or cu_private_event . Which of the three result tables a row references depends on the value of the uachm_reference_type column. The table uses all three columns as a composite primary key.

The ID of the row in the cu_useragent_clienthints table that is associated with the row referenced in the uachm_reference_id column.

Which table that this column references (and the associated column to join to) is dependent on the value in the uachm_reference_type column:

• 0 - This is a revision ID. The row will be in the cu_changes table, with the column to join to being cuc_this_oldid .
• 1 - This is a log ID. The row will be in the cu_log_event table, with the column to join to being cule_log_id .
• 2 - This is the ID for a row in the cu_private_event table, with the column to join to being cupe_id .

A integer mapping identifier that specifies which of the tables cu_changes , cu_log_event , or cu_private_event is referenced by the column uachm_reference_id. The valid mapping IDs for this column are stored in UserAgentClientHintsManager.php.

mysql> describe cu_useragent_clienthints_map;
+----------------------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+------------------+------+-----+---------+-------+
| uachm_uach_id | int(10) unsigned | NO | PRI | NULL | |
| uachm_reference_id | int(10) unsigned | NO | PRI | NULL | |
| uachm_reference_type | tinyint(1) | NO | PRI | 0 | |
+----------------------+------------------+------+-----+---------+-------+

mysql> show index in cu_useragent_clienthints_map;
+------------------------------+------------+--------------------+--------------+----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+------------------------------+------------+--------------------+--------------+----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| cu_useragent_clienthints_map | 0 | PRIMARY | 1 | uachm_uach_id | A | 0 | NULL | NULL | | BTREE | | |
| cu_useragent_clienthints_map | 0 | PRIMARY | 2 | uachm_reference_type | A | 0 | NULL | NULL | | BTREE | | |
| cu_useragent_clienthints_map | 0 | PRIMARY | 3 | uachm_reference_id | A | 0 | NULL | NULL | | BTREE | | |
| cu_useragent_clienthints_map | 1 | uachm_reference_id | 1 | uachm_reference_id | A | 0 | NULL | NULL | | BTREE | | |
+------------------------------+------------+--------------------+--------------+----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

• Wikimedia extension database tables