Manual:Templatelinks table

Contains for each current transclusion the id of the host page, the namespace number of the included page, and its title without namespace.

The target page may or may not exist, and due to renames and deletions may refer to different page records as time goes by. 

tl_from
Key to the  of the page containing the link.

tl_from_namespace
 of the page containing the link.

tl_namespace
Key to  of the target page.

Used in conjunction with tl_title.

tl_title
Key to  of the target page.

Used in conjunction with tl_namespace.

Schema summary
+---+--+--+-+-+---+ +---+--+--+-+-+---+ +---+--+--+-+-+---+
 * Field            | Type             | Null | Key | Default | Extra |
 * tl_from          | int(10) unsigned | NO   | PRI | 0       |       |
 * tl_from_namespace | int(11)         | NO   | MUL | 0       |       |
 * tl_namespace     | int(11)          | NO   | PRI | 0       |       |
 * tl_title         | varbinary(255)   | NO   | PRI |         |       |

+---+-+--+-+---+---+ +---+-+--+-+---+---+ +---+-+--+-+---+---+
 * Field            | Type                | Null | Key | Default   | Extra |
 * tl_from          | int(10) unsigned    | NO   | PRI | 0         |       |
 * tl_from_namespace | int(11)            | NO   |     | 0         |       |
 * tl_namespace     | int(11)             | NO   | PRI | 0         |       |
 * tl_title         | varchar(255) binary | NO   | PRI | 0         |       |

+---+-+--+-+---+---+ +---+-+--+-+---+---+ +---+-+--+-+---+---+
 * Field        | Type                | Null | Key | Default   | Extra |
 * tl_from      | int(10) unsigned    | NO   | PRI | 0         |       |
 * tl_namespace | int(11)             | NO   | PRI | 0         |       |
 * tl_title     | varchar(255) binary | NO   | PRI | 0         |       |

+---+-+--+-+---+---+ +---+-+--+-+---+---+ +---+-+--+-+---+---+
 * Field        | Type                | Null | Key | Default   | Extra |
 * tl_from      | int(8) unsigned     | NO   | PRI | 0         |       |
 * tl_namespace | int(8)              | NO   | PRI | 0         |       |
 * tl_title     | varchar(255) binary | NO   | PRI | 0         |       |