Abstract Data Types (PDM)

An abstract data type (ADT) is a user-defined data type which can encapsulate a range of data values and functions. The functions can be both defined on, and operate on the set of values.

Abstract data types can be used in the following ways in a Physical diagram:

Abstract data type is	Description
Created	You can create an abstract data type of any kind supported by your DBMS. If you create an abstract data type of type JAVA, you can link it to a Java class in an OOM to access the Java class properties (see Linking an abstract data type to a Java class).
Reverse engineered	An abstract data type in a database can be reverse engineered into a PDM. If you also reverse engineer the JAVA classes into an OOM, then the abstract data types of the type JAVA in the PDM are automatically linked to the Java classes in the OOM (see Reverse-engineering a PDM linked to an OOM)

Abstract data type is

Description

Created

You can create an abstract data type of any kind supported by your DBMS.

If you create an abstract data type of type JAVA, you can link it to a Java class in an OOM to access the Java class properties (see Linking an abstract data type to a Java class).

Reverse engineered

An abstract data type in a database can be reverse engineered into a PDM.

If you also reverse engineer the JAVA classes into an OOM, then the abstract data types of the type JAVA in the PDM are automatically linked to the Java classes in the OOM (see Reverse-engineering a PDM linked to an OOM)

For more information on reverse engineering a database into a PDM, see Reverse Engineering a Database into a PDM.

For more information on creating and reverse engineering Java classes into a PowerDesigner Object-Oriented Model, see Object-Oriented Modeling.

Depending on the current DBMS, the following kinds of abstract data types can be created in PowerDesigner:

Type	Description	Example
Array	Fixed length collection of elements	VARRAY (Oracle 8 and higher)
List	Unfixed length collection of objects	TABLE (Oracle 8 and higher)
Java	Java class	JAVA (Adaptive Server Anywhere, and Adaptive Server Enterprise)
Object	Contains a list of attributes and a list of procedures	OBJECT (Oracle 8 and higher)
SQLJ Object	Contains a list of attributes and a list of procedures	SQLJ OBJECT (Oracle 9i and higher)
Structured	Contains a list of attributes	NAMED ROW TYPE (Informix 9.x, and IBM DB2 5.2)

Example

An abstract data type for the Gregorian calendar which has functions defined to do the following:

Read and write roman numerals
Convert dates from the Julian calendar to the Gregorian calendar
Convert dates from the Gregorian calendar to the Julian calendar

Creating an Abstract Data Type
You can create an abstract data type from the Browser or Model menu.
Abstract Data Type Properties
To view or edit an abstract data type's properties, double-click its Browser or list entry. The property sheet tabs and fields listed here are those available by default, before any customization of the interface by you or an administrator.
Creating Object and SQLJ Object Abstract Data Types
If you select the OBJECT (or SQLJ OBJECT) type for an abstract data type, two additional tabs are displayed in the property sheet:
Linking an Abstract Data Type to a Java Class
You can specify a Java class in the PDM, and then link it to a Java class in an OOM. The OOM must be open in the current Workspace to be available for linking.

Parent topic: Physical Diagrams