Collaboration diagram for RDM Database Query APIs:

The RDM Database Query API contains a set of template classes used for querying data from RDM by different types of join.

Use these template classes to set up a static chain of encapsulated classes. Each class in the chain has a specific processing task and will fetch rows from the next class in the chain when needed for its computation.

At the head of the class chain, there can optionally be on transaction class:

Doing transactions is implemented by transaction

There are eight derived classes that can be used next, zero or more times in the chain:

Doing an inner join by a key is implemented by inner_join_by_key
Doing an outer join by a key is implemented by outer_join_by_key
Doing an inner join by a reference is implemented by inner_join_by_reference
Doing an outer join by a reference is implemented by outer_join_by_reference
Doing an inner join by referenced is implemented by inner_join_by_referenced
Doing an outer join by referenced is implemented by outer_join_by_referenced
Doing an inner join by referencing is implemented by inner_join_by_referencing
Doing an outer join by referencing is implemented by outer_join_by_referencing

A chain of these template classes is terminated with one instance of:

Doing a fetch of rows is implemented by read_row class.