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.