Wikicat Technical Design/Resource Relationship Entities
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Wikicat (and Wikicite) datamodel for expressing relationships between resources and the primary, FRBR-derived entities of Wikicat. This encompasses both
Resource Realtors
[edit]Defines the set of realtors (i.e. relationship types) that may exist between catalog resources.
> DESC resource_realtor; COLUMN TYPE DESC ---------------------------------------------------- realtor_code VARCHAR(5) Realtor type code/primary key NOT NULL name VARCHAR(25) Short name of the realtor NOT NULL TRANSLATABLE description VARCHAR(50) Description of the realtor NOT NULL TRANSLATABLE entity1_type VARCHAR(3) Type of first entity in the relationship; NOT NULL foreign key to table MODEL_ENTITY_TYPE entity2_type VARCHAR(3) Type of second entity in the relationship; NOT NULL foreign key to table MODEL_ENTITY_TYPE commutative BOOLEAN If the relationship is commuative NOT NULL transitive BOOLEAN If the relationship is transitive transactional BOOLEAN If the relationship is transactional, for example with a fixed duration
> select * from resource_realtor; realtor_code name entity_type1 entity_type1 commutative ---------------------------------------------------------------- exprs Expresses exp wrk FALSE mnfst Manifests mnf exp FALSE embdy Embodies itm mnf FALSE
Resource Relationships
[edit]> DESC resource_relationship; COLUMN TYPE DESC ---------------------------------------------------- res_rel_id INT(15) Primary key of the entity NOT NULL realtor_code VARCHAR(5) Relationship type; foreign key NOT NULL to RESOURCE_REALTOR entity1_type VARCHAR(3) Type of the first entity in the relationship; foreign key to table MODEL_ENTITY_TYPE entity1_id INT(15) Primary key of the first relationship entity; NOT NULL the actual table to which this key points is indicated by entity_type. entity2_type VARCHAR(3) Type of the second entity in the relationship;
The extent of a resource relationship, such as pages, playing time, etc. Note that there may be mutliple extents for a particular resource relationship when the extents are non-consecutive.
> DESC resource_rel_extent; COLUMN TYPE DESC ---------------------------------------------------- res_rel_x_id INT(15) Primary key of the entity res_rel_id INT(15) Resource relationship; foreign NOT NULL key to RESOURCE_RELATIONSHIP extent_type VARCHAR(3) Type of the extent NOT NULL extent_unit VARCHAR(3) Unit of the extent, for example, from NOT NULL EXPRESSION_EXTENT_UNIT_TYPE extent_begin VARCHAR(25) Beginning of the extent NOT NULL extent_end VARCHAR(25) End of the extent NOT NULL