Data Domain

Data Domain or sometimes just Domain defines the specific rules for an Attribute. It defines the data type used, set of allowable values, and any constraints that should be applied to the data in a column.

Different types of Data Domains:

• Atomic Domains - Define the specific type of data held by a single attribute, such as Description or Percentage.
• Reference Data - Used for mapping data to predefined lists.

For instance the Data Domain of an Attribute called HasChildren would have a data type of Boolean, because it is not a mandatory attribute it can accept null values. As such the only possible values for this column are true, false, or null.