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Db_Relation Class

Defined in: platform/classes/Db/Relation.php:9
Module: Db

This class lets you use relationships between Db two or many tables. You can pass all parameters to create single relation or pass an array of Db_Relations as first argument and they will be used together to build up an aggregate Db_Relation.

Constructor

Db_Relation

(
  • $table_name
  • [$foreign_key=null]
  • [$foreign_table=null]
  • [$join_type='LEFT']
)

Defined in platform/classes/Db/Relation.php:9

Parameters:

  • $table_name String | Array

    The name of main table in relation OR array of Db_Relations

  • [$foreign_key=null] Array optional

    Foreign key for relation an associative array of local => foreign field names, for example:

  • [$foreign_table=null] String optional

    Table to relate to

  • [$join_type='LEFT'] String optional

    Type of join to use

Example:

array('user.id' => 't.userId', 'i.item_id' => 't.item_id')

Methods

compile

()

Defined in platform/classes/Db/Relation.php:82

Before being used, a relation has to be compiled. Compiling finds the root table and levels from the root table, so joins can be constructed from the relation.

getLevel

(
  • $index
)
Array

Defined in platform/classes/Db/Relation.php:159

Returns a level of relations, from 1 to however many. Level 0 is the root table of the relation. The next level is all tables that have a foreign key to the root table. And so forth.
This is the order they should appear in JOIN statements, for the statements to make sense.

Parameters:

  • $index Integer

Returns:

Array:

getRelations

() Array

Defined in platform/classes/Db/Relation.php:148

Returns the array of Db_Relations this Db_Relation consists of. If null or empty, that means this Db_Relation is not a container.

Returns:

Array:

getRootTable

() String

Defined in platform/classes/Db/Relation.php:134

Returns the root table name, i.e. the unique foreign table that has no foreign key coming out of it.

Returns:

String:

Properties

$levels

Array

Defined in platform/classes/Db/Relation.php:180

Level 0 is the root table. This array contains the other levels... 1 through n where a table is on level k if there is a foreign key from it to a table on level k-1, and not to any other tables on levels below k-1.

$relations

Array protected

Defined in platform/classes/Db/Relation.php:66

The sub-relations comprising this relation

$was_compiled

Boolean protected

Defined in platform/classes/Db/Relation.php:74

Whether the relation has been compiled yet.