Analyzing Data › Defining Entity Types, Relationships, and Attributes › Defining Entity Type Attributes › Attribute Domain

Attribute Domain

The term domain refers to the collection of possible values for an attribute or set of attributes. Put another way, the domain of the attribute must include the set of all values that can actually be assigned to that attribute.

An attribute domain is:

• Primitive—A primitive domain is a collection of values that constrain the values of attributes or of parts of complex or user domains.
• CA Gen requires each attribute to be assigned to one of the following primitive domains:
  • Text—Each value is a string of characters.
  • Mixed Text—Each value is a combination of a double-byte character set and a single-byte character set.
  • DBCS Text—Each value is a double-byte character set.
  • Number—Each value is a number (positive or negative, integer, or real).
  • Date—Each value represents a date (including century).
  • Time—Each value represents an hour, minute, and second.
  • Time Stamp—Not relevant in analysis; it is dealt with during design.
  • GUI Object—Each value represents a pointer of an object linking and embedding (OLE) object. This option is available only with the workset attribute.
  • BLOB—Each value represents a variable sized Binary Large Object.
• Complex—A complex domain contains elements each of which has values that are constrained by a primitive domain.

  Some analysts consider the domains Date and Time to be complex domains that are based on the primitive domain Number. Dates and times are so universally important and uniquely configured that they are regarded here as primitive domains.

• User-defined—The first four primitive domains (Text, Number, Date, and Time) can be used as the basis for forming a hierarchy of other domains, named user-defined domains.

  Note: For more information, see Additional Data Modeling Topics.

The values of attributes from different primitive domains cannot usually be compared or used together in calculations. For example, it makes no sense to compare CUSTOMER Number with CUSTOMER Address. Makes no sense to multiply ORDER Quantity by Current Date. However, be required to add a number of days to a date.

The following table shows the primitive domains for the attributes of the entity type CUSTOMER.

*Assume that Phone Number includes parentheses and hyphens for readability.