PL/SQL User’s Guide and Reference - Phần 3

Defining and Declaring Collections To create collections, you define a collection type, then declare collections of that type. You can define TABLE and VARRAY types in the declarative part of any PL/SQL block, subprogram, or package. For nested tables, use the syntax TYPE type_name IS TABLE OF element_type [NOT NULL]; and for varrays, use the following syntax: TYPE type_name IS {VARRAY | VARYING ARRAY} (size_limit) OF element_type [NOT NULL]; where type_name is a type specifier used later to declare collections, size_limit is a positive integer literal, and element_type is any PL/SQL datatype except BINARY_INTEGER, PLS_INTEGER BOOLEAN BLOB, CLOB (restriction applies only to varrays) LONG, LONG RAW NATURAL, NATURALN NCHAR, NCLOB, NVARCHAR2 object types with BLOB or CLOB attributes (restriction applies only to varrays) object types with TABLE or VARRAY attributes POSITIVE, POSITIVEN REF CURSOR SIGNTYPE STRING TABLE VARRAY