RDM Database Query APIs

Data Structures
class	RDM::DB::QUERY::join_rows< table_id, NEXT >
	Template base class for doing a join. More...
class	RDM::DB::QUERY::join_rows_to_many< table_id, NEXT >
	Template base class for doing a join for one to many. More...
class	RDM::DB::QUERY::join_by_key< table_id, key_id, KEY_T, NEXT >
	Template base class for doing a join by key. More...
class	RDM::DB::QUERY::inner_join_by_key< table_id, key_id, KEY_T, NEXT >
	Inner join by key. More...
class	RDM::DB::QUERY::outer_join_by_key< table_id, key_id, KEY_T, NEXT >
	Outer join by key. More...
class	RDM::DB::QUERY::inner_join_by_referenced< table_id, ref_id, NEXT >
	Inner join by referenced. More...
class	RDM::DB::QUERY::outer_join_by_referenced< table_id, ref_id, NEXT >
	Outer join by referenced. More...
class	RDM::DB::QUERY::inner_join_by_reference< table_id, ref_id, NEXT >
	Inner join by reference. More...
class	RDM::DB::QUERY::outer_join_by_reference< table_id, ref_id, NEXT >
	Outer join by reference. More...
class	RDM::DB::QUERY::join_rows_to_one< table_id, NEXT >
class	RDM::DB::QUERY::inner_join_by_referencing< table_id, ref_id, NEXT >
	Inner join by referencing. More...
class	RDM::DB::QUERY::outer_join_by_referencing< table_id, ref_id, NEXT >
	Outer join by referencing. More...

Enumerations
enum	RDM::DB::QUERY::position { RDM::DB::QUERY::POS_NOT_SET = 0, RDM::DB::QUERY::POS_BEFORE_FIRST = 1, RDM::DB::QUERY::POS_ESTABLISHED_BEFORE_FIRST = 2, RDM::DB::QUERY::POS_SET = 3, RDM::DB::QUERY::POS_AFTER_LAST = -1 }
	The position in an ordered set of rows. More...

Detailed Description

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.

Enumeration Type Documentation

position

enum RDM::DB::QUERY::position

#include <rdm_db_query.h>

The position in an ordered set of rows.

The position in an ordered set of rows. This is used for many of the classes here to determine how to fetch the next or previous combination of rows for a join.

Enumerator
POS_NOT_SET	The position is not set and fetch_first or fetch_last has to be called to establish a position
POS_BEFORE_FIRST	The position for the cursor is set before its first position
POS_ESTABLISHED_BEFORE_FIRST	The position for the cursor is set before its first position as set by the cursor association. Navigating from this position can only be done if we navigate forward.
POS_SET	The position for the cursor is set at a normal row position
POS_AFTER_LAST	The position for the cursor is set after its last position

 {
POS_NOT_SET = 0, 
POS_BEFORE_FIRST = 1, 
POS_ESTABLISHED_BEFORE_FIRST = 2, 
POS_SET = 3, 
POS_AFTER_LAST = -1, 
 } position;