Creating Relations

Relations are typically created by calling the function Kure_RelationNew. The function Kure_RelationNew takes four parameters:

• unique: It is the manager, which will store the new relation. If unique equals NULL, KURE returns NULL and gives an error message.
• name: It is the name of the relation. This string will be copied. If name contains no characters, KURE returns NULL and gives an error message.
• height: It is the number of rows. If height is less then one, KURE returns NULL and gives an error message.
• width: It is the number of columns. If width is less then one, KURE returns NULL and gives an error message.

There are a number of (self declaring) functions in order to work with relations:

• Kure_RelationExists (RelManager *, char *): Returns 1, if a relation with the name exists in the manager.
• Kure_RelationGet (RelManager *, char *): Returns a pointer to the relation with the name, NULL if such a relation does not exist.
• Kure_RelationGetHeight (RelManager *, Kure_Rel *): Returns 0, if the manager or the relation is NULL.
• Kure_RelationGetWidth (RelManager *, Kure_Rel *): Returns 0, if the manager or the relation is NULL.
• Kure_RelationGetNumberOfEntries (RelManager *, Kure_Rel *): Returns -1, if the manager or the relation is NULL.
• Kure_RelationDelete (RelManager *, Kure_Rel *): Removes a relation from the manager.