ATK Relations: Difference between revisions

Latest revision as of 10:44, 8 March 2010

A relation defines a relation between two tables. One or more records in the first table belong to one or more records in the second table. A one to many relation would be '1 library has N books'. Below is a list of the relations that are currently available in ATK.

Relation	Description	Screenshot
atkOneToOneRelation	'A person has one address'
atkOneToManyRelation	'A department has many employees'
atkManyToOneRelation	'A project has a projectleader (that can lead multiple projects)'
atkManyToManyRelation	'A shopper buys multiple products, a product can be bought by multiple shoppers'
atkManyToManySelectRelation	'A shopper buys multiple products, a product can be bought by multiple shoppers'
atkManyBoolRelation	'An article has several categories, indicated with checkboxes'
atkManyToOneTreeRelation	'A category has a parent category'
atkMatrixRelation	'In a project, phases x and y depend on phases a and b'
atkSecureRelation	'A patient has personal information, that must be secured'
atkShuttleRelation	'An operator operates in several countries, selected from a list'
atkExtendableShuttleRelation	'An operator operates in several countries, selected from a list which can be filtered'

Relations behave similar to Attributes (in fact, relationships are nothing more then special attributes).

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-A relation defines a relation between two tables. One or more records in the first table belong to one or more records in the second table. A one to many relation would be '1 library has N books'.
+A relation defines a relation between two tables. One or more records in the first table belong to one or more records in the second table. A one to many relation would be '1 library has N books'. Below is a list of the relations that are currently available in ATK.
-= atkOneToOneRelation =
+{| border=1 cellpadding=5
-An atkOneToOneRelation defines a relation between two tables where there is one record in the first table that belongs to one record in the second table.
+ |- style="background-color: #FFFACD;"
+ ! Relation || Description || Screenshot
+ |-
+ | [[atkOneToOneRelation]] || 'A person has one address' ||
+ |-
+ | [[atkOneToManyRelation]] || 'A department has many employees' || [[Image:atkOneToManyRelation.png]]
+ |-
+ | [[atkManyToOneRelation]] || 'A project has a projectleader (that can lead multiple projects)' || [[Image:atkManyToOneRelation.png]]
+ |-
+ | [[atkManyToManyRelation]] || 'A shopper buys multiple products, a product can be bought by multiple shoppers' ||
+ |-
+ | [[atkManyToManySelectRelation]] || 'A shopper buys multiple products, a product can be bought by multiple shoppers' ||
+ |-
+ | [[atkManyBoolRelation]] || 'An article has several categories, indicated with checkboxes' || [[Image:atkManyBoolRelation.png]]
+ |-
+ | [[atkManyToOneTreeRelation]] || 'A category has a parent category' || [[Image:atkManyToOneTreeRelation.png]]
+ |-
+ | [[atkMatrixRelation]] || 'In a project, phases x and y depend on phases a and b' ||
+ |-
+ | [[atkSecureRelation]] || 'A patient has personal information, that must be secured' ||
+ |-
+ | [[atkShuttleRelation]] || 'An operator operates in several countries, selected from a list' || [[Image:atkShuttleRelation.png]]
+ |-
+ | [[atkExtendableShuttleRelation]] || 'An operator operates in several countries, selected from a list which can be filtered' ||
+ |}
-The atkOneToOneRelation supports two configurations: master mode and slave mode. The mode to use is detected automatically based on the value of the $refKey parameter.
+Relations behave similar to [[Attributes]] (in fact, relationships are nothing more then special attributes).
- function atkOneToOneRelation($name, $destination, $refKey="", $flags=0)
-* $name: The unique name of the attribute.
-* $destination: the destination node (in module.nodename notation)
-* $refKey: foreign-key field (master mode) or empty (slave mode)
-== Master mode example ==
-The node in which the relation is implemented, is considered the master (code is in node A). And the referential key pointing to the master record (a_id) is in the destination node (node B).
-[[image:atkOneToOne_master.jpg|center]]
-Referential key a_id is in the other node, so this is the master-configuration.
-== Slave mode example ==
-The node in which the relation is implemented (code is in node B), is considered the child. And the referential key pointing to the master record (a_id) is in the current node (node B).
-[[image:atkOneToOne_slave.jpg|center]]
-Referential key a_id is in the same node, so this is the slave-configuration.
-= atkOneToManyRelation =
- function atkOneToManyRelation($name, $destination, $refKey="", $flags=0)
-* $name The unique name of this relation within a node ''- In contrast with moth other attributes, the name does not correspond to a database field. This is because in one2many relations, the databasefield that stores the link, is in the destination node (B) and not in the owner node (A)''
-* $destination The node to which the relationship is made
-* $refKey For regular oneToMany relationships, $refKey is name of the referential key in the destination node. In the case of multi-foreign key relationships, $refKey can be an array of fields.
-'''Example'''
-Suppose a department (node A) has many employees (node B). To edit the list of employees in a department, this relationship can be built with an atkOneToManyRelation. Each employee gets a department_id (a_id).
-[[image:atkOneToMany.jpg|center]]
-= atkManyToOneRelation =
- function atkManyToOneRelation($name, $destination, $flags=0)
-* $name The name of the attribute.
-* $destination The node we have a relationship with.
-'''Example'''
-Projects all have one coordinator (node B), but one coordinator can have multiple projects (node A). So in the project class, there's a atkManyToOneRelation to a coordinator.
-[[image:atkManyToOne.jpg|center]]
-= Many-To-Many-Relation =
-This relation can be created with an intermediate table to store the relations.
-A Many-To-Many-Relation basically consist of a atkOneToMany relation to the intermediate table. The intermediate node has two atkManyToOne relations defined.
-'''Example'''
-One person (node A) can have several skills (node B) and the same skill applies to more than one person.
-[[image:atkManyToMany.jpg|center]]
-If, in the example above, a skill is removed, this skill must be removed for all employees. This can be achieved by adding the AF_CASCADE_DELETE flag to the atkOneToManyRelation in node B:
- atkOneToMany(“unique dummy”,
-              “mymod.A_B”,
-              “b_id”,
-              AF_HIDE|AF_CASCADE_DELETE);
-Normally you assign skills to a person (an not the other way round), so the atkOneToManyRelation in this node must be hidden.
-And on the other hand, if an employee is deleted, the correspoding record(s) in the intermediate table must be removed as well.
- atkOneToMany(“unique dummy”,
-              “mymod.A_B”,
-              “a_id”,
-              AF_CASCADE_DELETE);