When you configure a reference data set as dependent, the reference data set that it depends on is referred to as the parent dependency. Reference data sets can have only one parent dependency. When you create code lists in a dependent reference data set, the code lists inherit the same parent dependency.

After you create a dependent reference data set, you cannot change the structure definition. If you create a code list in a dependent reference data set, the code list must use the inherited structure definition.

For example, you have a Country Codes reference data set. When you create a State Codes reference data set, you define the structure definition as dependent and configure the Country Codes reference data set as the parent dependency. Then when you create code lists in the State Codes reference data set, the code lists inherit the dependency on the Country Codes reference data set. For each code list in the State Codes reference data set, you can choose the code list dependency. A code list dependency defines the dependent relationship between one code list and another. You might want the Enterprise State Codes code list to depend on the Enterprise Country Codes code list.