Collection Tree Hierarchy

Collection Tree Hierarchy

Tables: VY_COLLECTION

In Vine, collections are organized into a tree hierarchy:

Figure 12. Tree of collections in Vine for Windows

Top-level collections are the collections that have the TOPLEVEL field set to 1. They start the branches of the collection tree and cannot be included into any other collections or have parent collections.

NOTE: Top-level collections replace collection types used in previous versions of Vine for Windows. However, collection types are still supported with special triggers for backward Vine for Windows client compatibility.

All top-level collections can be obtained with the following SQL:

select * from vineyarddb.vy_collection_view where TOPLEVEL = 1 and status='B'

Collections include other objects. Objects "included" into a collection are actually connected to it with the "Belongs-Member" connection. For instance, if a collection includes other child collections, then the type of connection used is 21. The following SELECT gives the names of all child collections of a randomly taken top-level collection:

select name from vineyarddb.vy_collection_view where

id in (select fromobjectid from vineyarddb.vy_connection_view where targetobjectid in (select id from vineyarddb.vy_collection_view where TOPLEVEL = 1 and status='B' and rownum =1) and connectiontype = 21 and status='B');

Collections including other collections can be of the Excluding type, i.e. its Excluding field is set to 1. It means that within that collection any object can be included into a single sub-collection only. Developers should respect and check the Excluding flag themselves, there is currently no check of this flag in the PL/SQL InsertConnection procedure which should be used to include objects into collections. For a code example please refer to the InsertConnection section of the SQL API chapter.