Defining attributes and data in the entity/attribute editor
Through the Attributes grid you define attributes for the current entity and data elements that can be reused in other entities or other SA design activities (i.e., process modeling, Data Flow diagrams). The following properties are displayed by default if a DBMS has not been specified for the current diagram.
Data
The Defining Data Elements instantiated by the attribute.
Name
The name of the attribute.
Primary Key
Whether the attribute is a primary key component. System Architect automatically creates a unique Primary Key index definition based on the composite of all attributes which have been specified as being primary key components.
FK
Whether the attribute is the result of foreign key migration. This field is set by System Architect and is not user-modifiable.
Allow Null
Whether the database column represented by the attribute can contain a null value. If the attribute is a propagated foreign key, the field is set by System Architect and is not user-modifiable.
Unique
Whether the attribute represents a candidate key. The value of this field is transferred to the Physical Data Model (PDM) when it is generated from the ERD.
Data Type
The Standard Data Type for the data element represented by the attribute. The choices provided are based on the SQL 92 standard; extensions have been provided to account for DBMS-specific data types for which there is no SQL 92 equivalent. 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 data element, the default qualifier is 10.
Column Name
The name of the column created from the attribute when a Physical Data Model is created from the ERD. The default is the name of the data element. (Use Dictionary > Options > Column Name Options to write a script that sets defaults for column names.)
Default Value
The default value of a non-null attribute.
Domain
The Data Domain from which the data element inherits datatype and qualifiers. The properties specified in the data domain definition overrule properties in the data element. Any change made to the domain are cascaded to all attributes and data elements inheriting from that domain.
When a physical data model is generated from an ERD, a User Data Type is produced for all relevant data domains. Columns inherit properties from UDT exactly as data elements inherit from domains.
Grid Row Number
The sequence number of each attribute.
Grid Button
These buttons operate on the row or cell that is currently in focus.