Extended Data Type (EDT) in Ax2012

• EDT is user defined definition of a primitive datatype.
• EDT extends primitive datatypes or other EDT's.
• The benefit of creating EDT is reuse of their properties, Another benefit is more efficient maintenance.  

Create Extended Data Type:

You can create an extended data type in the Application Object Tree (AOT), and then base a table field on this type.

1. In the AOT, click Data Dictionary.
2. Right-click Extended Data Types, click New, and then click a data type to base the extended data type on.
3. Right-click the extended data type you created in step 2, and then click Properties.
4. To base the extended data type on another extended data type, select an extended data type from the Extends property list.
5. The list of available extended data types varies, depending on the base data type that you selected in step 2.
6. Modify additional properties, as needed.

Press CTRL+S to save the extended data type.