Projection

Projection — Projection.

Synopsis


#include <libhrel/relation.h>


            HRelationProject;
HRelation*  h_relation_project              (HRelation *relation,
                                             ...);
HRelation*  h_relation_project_l            (HRelation *relation,
                                             GSList *list);

Object Hierarchy


  GObject
   +----HRelation
         +----HRelationProject

Description

Details

HRelationProject

typedef struct _HRelationProject HRelationProject;

A HRelation representing a projected relation.

h_relation_project ()

HRelation*  h_relation_project              (HRelation *relation,
                                             ...);

Creates a relation on relation projected over a set of attributes.

`relation` :	relation to project
`...` :	name of an attribute, followed by another and so on, then a `NULL`
Returns :	projected relation

h_relation_project_l ()

HRelation*  h_relation_project_l            (HRelation *relation,
                                             GSList *list);

A variation of h_relation_project() taking a GSList of attribute names.

`relation` :	relation to project
`list` :	list of attribute names
Returns :	projected relation