Properties of collection data types
Valid element data types
You can create a collection with elements of any data type
listed in your project except SERIAL, SERIAL8, and BIGSERIAL. You
can define a collection type of an existing collection or row data
type. For example, you can define a list of a set of integers in SQL:
LIST(SET(integer not null))You can
also create collections of opaque or distinct data types.
Tip: If
you create a collection with an element of type BLOB or CLOB, you
can test for the existence of a particular sbspace when your module
is being registered in a database by using .
Type constructors
The type
constructor determines the structure of the collection. The following
table shows the options between the type constructors.
| Constructor | Elements Ordered? | Duplicates Allowed? |
|---|---|---|
| LIST | Yes | Yes |
| MULTISET | No | Yes |
| SET | No | No |