Overview of foreign database constraint definitions
A constraint definition is a property assigned to one column or a set of columns to guarantee data consistency and integrity. You can define the following constraint definitions in your OpenEdge meta schema which you want to migrate to a foreign data source:
Primary key constraint definition — Ensures that each row in a table is uniquely identifiable. Primary keys require a value that is not NULL or NULL-capable. There can only be one primary key, and one primary key constraint definition per table.
Unique key constraint definition — Enforces uniqueness in a column or set of columns. You can have multiple unique key constraint definitions per table.
Foreign key constraint definition — Prevents record updates that break foreign key relationships between tables.
Check constraint definition — Defines an evaluation expression for data validation during an update to a field or insertion of a new row.
Default constraint definition — Defines an initial value for a field.
Clustered index "mock" constraint definition — Defines the index that orders the way records are physically stored in the database. There can be only one clustered index constraint definition per table.This is not an actual constraint definition, and so it is termed a "mock" constraint definition that the definition of the clustered index is migrated to the MS SQL Server database like the other constraint definitions.
Primary key constraint definition — Ensures that each row in a table is uniquely identifiable. Primary keys require a value that is not NULL or NULL-capable. There can only be one primary key, and one primary key constraint definition per table.