How to Reuse Object Definitions

There are several ways to reuse object definitions:

• Create a new instance of an existing definition. For example, if you have a standard Demography Table, you can use it in multiple studies simply by creating a new instance of it for each study. No additional validation of the definition is necessary.
• Copy a definition and modify it as necessary. If a new study requires an extra column in the Demography Table, for example, you can copy the standard Demography Table definition and add a column to it for use in the new study. You must revalidate the definition, but the definition process is simpler than recreating the whole Table.
• Modify an existing definition. If you discover a bug in a Program, for example, that should be fixed in all instances of the Program, you can modify the definition (if you have the necessary privileges) working through an instance of the Program. You can upgrade any or all instances of the original Program to the fixed version of the definition by running a job. (If you have the necessary privileges, you can also modify the definition directly in the Library. However, you cannot run the Program without creating an instance of it in a Work Area.)

  This method is also appropriate for modifying standard company definitions as they require change over time. For example, you may decide to add the new column to your standard Demography Table. In that case, you can create a new instance of the standard Table and add the column to the standard Table definition through the new instance.

  Existing instances of the original standard Demographic Table continue to point to the original version. You can upgrade any or all of them to the new definition if you so choose.