Object Type Specification Syntax v13

The following is the syntax of the object type specification:

CREATE [ OR REPLACE ] TYPE <name>
  [ AUTHID { DEFINER | CURRENT_USER } ]
  { IS | AS } OBJECT
( { <attribute> { <datatype> | <objtype> | <collecttype> } }
    [, ...]
  [ <method_spec> ] [, ...]
  [ <constructor> ] [, ...]
) [ [ NOT ] { FINAL | INSTANTIABLE } ] ...;

where method_spec is the following:

[ [ NOT ] { FINAL | INSTANTIABLE } ] ...
[ OVERRIDING ]
  <subprogram_spec>

where subprogram_spec is the following:

{ MEMBER | STATIC }
{ PROCEDURE <proc_name>
    [ ( [  SELF [ IN | IN OUT ] <name> ]
        [, <parm1> [ IN | IN OUT | OUT ] <datatype1>
                   [ DEFAULT <value1> ] ]
        [, <parm2> [ IN | IN OUT | OUT ] <datatype2>
                   [ DEFAULT <value2> ]
        ] ...)
    ]
|
  FUNCTION <func_name>
    [ ( [  SELF [ IN | IN OUT ] <name> ]
        [, <parm1> [ IN | IN OUT | OUT ] <datatype1>
                   [ DEFAULT <value1> ] ]
        [, <parm2> [ IN | IN OUT | OUT ] <datatype2>
                   [ DEFAULT <value2> ]
        ] ...)
    ]
  RETURN <return_type>
}

where constructor is the following:

CONSTRUCTOR FUNCTION <func_name>
  [ ( [ <parm1> [ IN | IN OUT | OUT ] <datatype1>
                 [ DEFAULT <value1> ] ]
      [, <parm2> [ IN | IN OUT | OUT ] <datatype2>
                 [ DEFAULT <value2> ]
      ] ...)
  ]
RETURN <return_type>;

name is an identifier (optionally schema-qualified) assigned to the object type.

If the AUTHID clause is omitted or DEFINER is specified, the rights of the object type owner are used to determine access privileges to database objects. If CURRENT_USER is specified, the rights of the current user executing a method in the object are used to determine access privileges.

attribute is an identifier assigned to an attribute of the object type.

datatype is a base data type.

objtype is a previously defined object type.

collecttype is a previously defined collection type.

Following the closing parenthesis of the CREATE TYPE definition, [ NOT ] FINAL specifies whether or not a subtype can be derived from this object type. FINAL, which is the default, means that no subtypes can be derived from this object type. Specify NOT FINAL if you want to allow subtypes to be defined under this object type.

Following the closing parenthesis of the CREATE TYPE definition, [ NOT ] INSTANTIABLE specifies whether or not an object instance can be created of this object type. INSTANTIABLE, which is the default, means that an instance of this object type can be created. Specify NOT INSTANTIABLE if this object type is to be used only as a parent “template” from which other specialized subtypes are to be defined. If NOT INSTANTIABLE is specified, then NOT FINAL must be specified as well. If any method in the object type contains the NOT INSTANTIABLE qualifier, then the object type, itself, must be defined with NOT INSTANTIABLE and NOT FINAL.

method_spec denotes the specification of a member method or static method.

Prior to the definition of a method, [ NOT ] FINAL specifies whether or not the method can be overridden in a subtype. NOT FINAL is the default meaning the method can be overridden in a subtype.

Prior to the definition of a method specify OVERRIDING if the method overrides an identically named method in a supertype. The overriding method must have the same number of identically named method parameters with the same data types and parameter modes, in the same order, and the same return type (if the method is a function) as defined in the supertype.

Prior to the definition of a method, [ NOT ] INSTANTIABLE specifies whether or not the object type definition provides an implementation for the method. If INSTANTIABLE is specified, then the CREATE TYPE BODY command for the object type must specify the implementation of the method. If NOT INSTANTIABLE is specified, then the CREATE TYPE BODY command for the object type must not contain the implementation of the method. In this latter case, it is assumed a subtype contains the implementation of the method, overriding the method in this object type. If there are any NOT INSTANTIABLE methods in the object type, then the object type definition itself, must specify NOT INSTANTIABLE and NOT FINAL following the closing parenthesis of the object type specification. The default is INSTANTIABLE.

subprogram_spec denotes the specification of a procedure or function and begins with the specification of either MEMBER or STATIC. A member subprogram must be invoked with respect to a particular object instance while a static subprogram is not invoked with respect to any object instance.

proc_name is an identifier of a procedure. If the SELF parameter is specified, name is the object type name given in the CREATE TYPE command. If specified, parm1, parm2, … are the formal parameters of the procedure. datatype1, datatype2, … are the data types of parm1, parm2, … respectively. IN, IN OUT, and OUT are the possible parameter modes for each formal parameter. If none are specified, the default is IN. value1, value2, … are default values that may be specified for IN parameters.

Include the CONSTRUCTOR FUNCTION keyword and function definition to define a constructor function.

func_name is an identifier of a function. If specified, parm1, parm2, … are the formal parameters of the function. datatype1, datatype2, … are the data types of parm1, parm2, … respectively. IN, IN OUT, and OUT are the possible parameter modes for each formal parameter. If none are specified, the default is IN. value1, value2, … are default values that may be specified for IN parameters. return_type is the data type of the value the function returns.

The following points should be noted about an object type specification:

• There must be at least one attribute defined in the object type.

• There may be none, one, or more methods defined in the object type.

• A static method cannot be overridden (OVERRIDING and STATIC cannot be specified together in method_spec).

• A static method must be instantiable (NOT INSTANTIABLE and STATIC cannot be specified together in method_spec).