The name of the column. A column can be created from an existing data elements: drag a name from the list displayed when the Choices button is clicked. The default name may be changed. If the PDM was created from an ERD, the name of the column defaults to the name of the data element in the entity. For more control over column names, see Dictionary > Options > Column Name Options.
Primary Key
Whether the column is a primary key component. System Architect automatically creates a unique Primary Key index definition based on the composite of all columns which have been specified as being primary key components.
The primary key of an entity is the attribute, or attributes, that uniquely identifies an instance of the record represented by the entity. The primary key of a table is the column or columns that uniquely identifies an instance of the record represented by the table.
FK
Whether the column is the result of foreign key migration. This field is set by System Architect and is not user-modifiable.
Allow Null
Whether the column can contain a null value. Primary keys may never be null.
Unique
Whether the column represents a candidate key. When generating schemas from the PDM, a unique column constraint is generated for columns specified as unique (providing the DBMS supports unique column constraints). Primary keys are by definition unique. In some DBMS non-key columns may be unique.
Data Type
The Standard Data Type for the column. The choices provided are based on the target DBMS. The default data type value is character. Use USRPROPS.TXT to define your own datatypes.
Qualifiers
The length, precision, and other qualifiers for the selected data type. When you create a new column the default qualifier is 10.
Default Value
The default value of a non-null column.
Domain
The user data type from which the column inherits datatype and qualifiers. The properties specified in the data domain definition overrule properties in the column. Any change made to the domain is cascaded to all columns inheriting from that domain.
User Data Types are the physical equivalent of a data domain. They can be used to establish business rules and enforce uniformity in the system design and the database. When an entity relation diagram is used to create a physical data model, all data domains used by attributes in entities in the ERD are used to create UDTs.