Collection Method Call

A collection method is a built-in PL/SQL subprogram that returns information about a collection or operates on a collection.

Topics:

• Syntax

• Semantics

• Examples

• Related Topics

Syntax

collection_method_call ::=

Description of the illustration collection_method_call.gif

Semantics

collection_name

The name of a collection.

COUNT

A function that returns the current number of elements in the collection, described in "COUNT Method".

DELETE

A procedure that deletes elements from the collection, described in "DELETE Method".

Restriction on DELETE If collection_name identifies a varray, you cannot specify indexes with DELETE.

index

A numeric expression whose value has data type PLS_INTEGER or a data type that can be implicitly converted to PLS_INTEGER (see Table 3-10, "Possible Implicit PL/SQL Data Type Conversions").

EXISTS

A function that returns TRUE if the indexth element of the collection exists and FALSE otherwise. For more information, see "EXISTS Method".

Restriction on EXISTS You cannot use EXISTS if collection_name identifies an associative array.

EXTEND

A procedure that increases the size of the collection, described in "EXTEND Method".

Restriction on EXTEND You cannot use EXTEND if collection_name identifies an associative array.

FIRST

A function that returns the first subscript or key value in the collection, described in "FIRST and LAST Methods".

LAST

A function that returns the last subscript or key value in the collection, described in "FIRST and LAST Methods".

LIMIT

A function that returns the maximum number of elements that the collection can have. If the collection has no maximum size, LIMIT returns NULL. (For an example, see "LIMIT Method".

NEXT

A function that returns the subscript that succeeds index n. If n has no successor, NEXT(n) returns NULL. For more information, see "PRIOR and NEXT Methods".

PRIOR

A function that returns the subscript that precedes index n in a collection. If n has no predecessor, PRIOR(n) returns NULL. For more information, see "PRIOR and NEXT Methods".

TRIM

A procedure that deletes elements from the end of a collection, described in "TRIM Method".

Restriction on TRIM You cannot use TRIM if collection_name identifies an associative array.

number

The number of elements to delete from the end of a collection. The default is one.

Examples

• Example 5-28, "Checking Whether a Collection Element EXISTS"

• Example 5-29, "Counting Collection Elements with COUNT"

• Example 5-30, "Checking the Maximum Size of a Collection with LIMIT"

• Example 5-31, "FIRST and LAST Methods"

• Example 5-32, "PRIOR and NEXT Methods"

• Example 5-34, "EXTEND Method"

• Example 5-35, "TRIM Method"

• Example 5-37, "DELETE Method"

Related Topics

In this chapter:

• "Collection"

In other chapters:

• "Collection Methods"