documentation:facet_idx_def_example
Example: Adding a Material Type (947$t) facet index
First, every database script should perform its work inside a transaction. This is to protect the consistency of the data and avoid partial implementation of desired changes in the case of an error.
BEGIN;
Now we need to add the indexing definition:
INSERT INTO config.metabib_field (field_class, name, xpath, format, label, search_field, facet_field) VALUES ( 'identifier', -- The class to which this definition will belong 'mattype', -- The symbolic name of the definition within the class $$//marc:datafield[@tag="947"]/marc:subfield[@code="t"]$$, -- The XPath expression which will extract the desired data from the MARCXML 'marcxml', -- The format in which we will process the XPath for this definition 'Material Type', -- The translatable label used for this definition in user interfaces FALSE, -- Mark this definition as NOT search-oriented TRUE -- Mark this definition as a facet-oriented index );
Allowing the default id value to be set by the database gives us the ability to use the CURRVAL() function for the auto-incrementing sequence that fills in the id. We can use this when populating the normalization map and the index table with data from the MARC record:
INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about -3 -- Ordering of normalizer application -- this one first FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Up-case'; -- The normalizers we care about for this field INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, params, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about '["[",""]', -- Parameters for the Replace function -- replace "[" with the empty string -2 -- Ordering of normalizer application -- this one second FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Replace'; -- The normalizers we care about for this field INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, params, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about '["]",""]', -- Parameters for the Replace function -- replace "]" with the empty string -1 -- Ordering of normalizer application -- this one third FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Replace'; -- The normalizers we care about for this field
In order to avoid reindexing the entire bibliographic data set for all index definitions when simply adding a new definition, it is best to backfill the index table for the new definition. This is done by pulling data from the existing, flattened MARC data:
INSERT INTO metabib.facet_entry (FIELD, SOURCE, VALUE) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above mfr.record, -- The source MARC record from which the data will be extracted UPPERCASE(BTRIM(VALUE,'[]')) -- Normalize 947$t data using the same logic as the defined above for initial index population FROM metabib.real_full_rec AS mfr -- The internal table holding a flattened version of the bibliographic record WHERE mfr.tag = '947' AND subfield = 't'; -- Include only subfield t from 947 tags
If an alias is desired for targeting exactly this field in SRU and Z39.50 searches, that can be added as well:
INSERT INTO config.metabib_search_alias (alias, field_class, FIELD) VALUES ( 'eg.mattype', -- Alias to accept in SRU/CQL queries, and to map in Z39.50 settings 'identifier', -- The search class to which the definition belongs CURRVAL('config.metabib_field_id_seq'::regclass) -- Returns the id of the indexing definition inserted above );
The only thing left to do is have the database commit the transaction wrapping all of these commands. The final script thus ends up as:
BEGIN; INSERT INTO config.metabib_field (field_class, name, xpath, format, label, search_field, facet_field) VALUES ( 'identifier', -- The class to which this definition will belong 'mattype', -- The symbolic name of the definition within the class $$//marc:datafield[@tag="947"]/marc:subfield[@code="t"]$$, -- The XPath expression which will extract the desired data from the MARCXML 'marcxml', -- The format in which we will process the XPath for this definition 'Material Type', -- The translatable label used for this definition in user interfaces FALSE, -- Mark this definition as NOT search-oriented TRUE -- Mark this definition as a facet-oriented index ); INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about -3 -- Ordering of normalizer application -- this one first FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Up-case'; -- The normalizers we care about for this field INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, params, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about '["[",""]', -- Parameters for the Replace function -- replace "[" with the empty string -2 -- Ordering of normalizer application -- this one second FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Replace'; -- The normalizers we care about for this field INSERT INTO config.metabib_field_index_norm_map (FIELD, norm, params, pos) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above cin.id, -- The ids of the normalizers we care about '["]",""]', -- Parameters for the Replace function -- replace "]" with the empty string -1 -- Ordering of normalizer application -- this one third FROM config.index_normalizer AS cin -- Table defining normalizer functions WHERE cin.name = 'Replace'; -- The normalizers we care about for this field INSERT INTO metabib.facet_entry (FIELD, SOURCE, VALUE) SELECT CURRVAL('config.metabib_field_id_seq'::regclass), -- Returns the id of the indexing definition inserted above mfr.record, -- The source MARC record from which the data will be extracted UPPERCASE(BTRIM(VALUE,'[]')) -- Normalize 947$t data using the same logic as the defined above for initial index population FROM metabib.real_full_rec AS mfr -- The internal table holding a flattened version of the bibliographic record WHERE mfr.tag = '947' AND subfield = 't'; -- Include only subfield t from 947 tags INSERT INTO config.metabib_search_alias (alias, field_class, FIELD) VALUES ( 'eg.mattype', -- Alias to accept in SRU/CQL queries, and to map in Z39.50 settings 'identifier', -- The search class to which the definition belongs CURRVAL('config.metabib_field_id_seq'::regclass) -- Returns the id of the indexing definition inserted above ); COMMIT;
documentation/facet_idx_def_example.txt · Last modified: 2022/02/10 13:34 by 127.0.0.1