ProDataRelationMetaData class

OpenEdge provides a Java class, com.progress.open4gl.ProDataRelationMetaData, that allows you to specify and access the definition of a given data-relation. A single data-relation defines a relationship between a parent ProDataObject collection and a child ProDataObject collection within a ProDataGraph. Thus, a ProDataRelationMetaData object represents schema information that is defined as part of a corresponding ProDataGraphMetaData object. To specify parent-child relationships, each data-relation names the column properties (fields) in parent and child ProDataObject types that form a primary-foreign key relationship between a given parent ProDataObject instance and one or more child ProDataObject instances.

You can use a data-relation to retrieve child records related to the parent. A parent ProDataObject instance (representing a single table row) contains a list of references to the related child ProDataObject instances (representing one or more table rows). For a each data-relation, these references are represented in every parent row as a many-valued reference property in order to support multiple child rows. After you instantiate a ProDataGraph and add all ProDataObject instances, you can then call the ProDataGraph setChildTableReferences( ) method, which uses the specified key relationships to create all the child reference property lists in each parent ProDataObject as provided by the data-relations defined for the ProDataGraph.

A ProDataGraphMetaData object can have multiple ProDataRelationMetaData objects. Each ProDataRelationMetaData object typically maps to a particular data-relation object in a corresponding ABL ProDataSet.

The com.progress.open4gl.ProDataRelationMetaData class contains with the following constructors and methods.