Data dictionaries support three types of constraint definitions: field-level, record-level, and referential integrity. While there are some similarities between these various types of constraints, the steps you take to implement them are quite different. As a result, the creation of each constraint type is described in its own section.

Both field-level and record-level constraints are actually properties of dictionary-bound tables. There are other field and table-related properties as well. The need to discuss constraints provides us with a fine opportunity to consider these properties in general.