About Constraints

You can define Constraints to enforce limitations on data in each row of a table.

You can define Constraints to enforce limitations on data in each row of a table. Oracle Life Sciences Data Hub automatically generates an index based on the Primary Key Constraint. Oracle LSH Constraints and indexes appear as Oracle table constraints and indexes for Oracle technology Programs and as SAS data set constraints and indexes for SAS technology Programs.

You must define the Table's Columns before you can define Constraints.

Constraints are different from other Oracle LSH defined objects in that they belong to the Table instance as well as to the definition. If you define or modify a Constraint in a Table instance in a Work Area, the resulting Constraint is part of the Table instance but not the Table definition on which it is based. The only way to make a Constraint a part of the Table definition is to go to the definition directly in the Application Area or Domain and add it there. After you have added a Constraint to a Table definition, all Table instances created from it also have that Constraint defined. You can delete the Constraint from the Table instance if you want to.

You must define a Primary or Unique Key for a Table in order to perform most types of data processing (see Data Processing Types).

Note:

Oracle LSH supports the standard Oracle Not Null constraint, but you define it as a Column attribute, not through the Table Constraints user interface.

To create a Constraint:

1. In the Constraints/Indexes subtab of a Table, click Add.

   The system displays the Create Constraint screen.

2. Enter values in the following fields:
   • Name. See Naming Objects.
   • Description. See Creating and Using Object Descriptions.
   • Type. Choose the type of Constraint. The system refreshes the display of the lower portion of the screen depending on which type you choose. The definition procedure varies by type: see Check Constraint, Primary Key, Unique Key.
3. Click Apply.