Fix search path for psql function

This ensures that all calls of the function use the expected searchpath
and the tables of our schema can be found.
As our migration-import doesn't set the searchpath when inserting new
documents but uses fully qualified table names this leads to the job
failing as it is not finding the tables.

RISDEV-6261

Author: malte-laukoetter

backend/src/main/resources/db/migration/V0.25__fix_searchpath_for_function.sql

@@ -0,0 +1,26 @@
+CREATE OR REPLACE FUNCTION update_eli_tables()
+    RETURNS trigger AS
+$$
+BEGIN
+    INSERT INTO norm_expression
+    VALUES (
+               -- see definition of dokumente.eli_norm_manifestation
+               ((xpath(
+                       '//*[local-name()="act"]/*[local-name()="meta"]/*[local-name()="identification"]/*[local-name()="FRBRExpression"]/*[local-name()="FRBRuri"]/@value'::text,
+                       NEW.xml))[1])::text)
+    ON CONFLICT DO NOTHING;
+    INSERT INTO norm_manifestation
+    VALUES (
+               -- see definition of dokumente.eli_norm_manifestation
+               (regexp_replace(((xpath(
+                       '(//*[local-name()="act"]/*[local-name()="meta"]/*[local-name()="identification"]/*[local-name()="FRBRManifestation"]/*[local-name()="FRBRuri"]/@value)'::text,
+                       NEW.xml))[1])::text, '/[^/]*$'::text, ''::text)),
+               -- see definition of dokumente.eli_norm_expression
+               ((xpath(
+                       '//*[local-name()="act"]/*[local-name()="meta"]/*[local-name()="identification"]/*[local-name()="FRBRExpression"]/*[local-name()="FRBRuri"]/@value'::text,
+                       NEW.xml))[1])::text)
+    ON CONFLICT DO NOTHING;
+    RETURN NEW;
+END;
+$$
+    LANGUAGE 'plpgsql' VOLATILE SET search_path from current;