In System Architect you can define data structures to group data elements that are commonly used together, such as the individual components of an address, to simplify your design process.
Data models traditionally use atomic units of data, such as what is represented by a data element; therefore, the data structure is not a standard component of an entity relation model and is not maintained as a structure within the entity definition. The data structure does, however, provide a convenient means of grouping data elements that are commonly used together.
For example, an address usually includes a street, city, state, and zip code. The data structure allows you to group the components of the address so that you do not have to enter each component into the entity.
System Architect automatically decomposes the data structure into its elements when you use it in an entity definition, creating an attribute for each element defined in the data structure.
To define a data structure
1 Click Dictionary > New Definition.
2 Select Data Structure as the Type.
3 Enter the name of the data structure, and then click OK.
4 Enter the names of the elements or other data structures included in the data structure either by typing the data names or by dragging the names of defined data items from the list opened by the Choices button.
5 Use Elem to define each undefined data element included in the structure, or Struct to define a nested data structure. Enter the data properties into the data items definition dialog, and then click OK to save the definition.
6 If you enter a value in the SadataColumn Prefix property field, the prefix is applied to all attribute and column names when the data structure is used in an entity.
7 Click OK to save the data structure and data element definitions.
You are not required to define a data element when adding it to a data structure definition, System Architect maintains a list of undefined data items. You can access this list using the Create Undefined List command from the Dictionary menu.
If you use a data structure in an entity definition, and the data structure is defined by undefined data, default definitions are automatically assigned to the undefined data elements. As a result, you can give default values to data element definitions without realizing it.
