LP#1527342 SQL getting started

Signed-off-by: Bill Erickson <berickxx@gmail.com>

diff --git a/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.decouple_co_history.sql b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.decouple_co_history.sql
new file mode 100644 (file)
index 0000000..5065ae6
--- /dev/null
+++ b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.decouple_co_history.sql
@@ -0,0 +1,99 @@
+
+BEGIN;
+
+-- TODO process to delete history items once the age threshold 
+-- history.circ.retention_age is reached?
+
+-- SELECT evergreen.upgrade_deps_block_check('XXXX', :eg_version); 
+
+CREATE TABLE action.usr_circ_history (
+    id           BIGSERIAL PRIMARY KEY,
+    usr          INTEGER NOT NULL REFERENCES actor.usr(id)
+                 DEFERRABLE INITIALLY DEFERRED,
+    xact_start   TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW(),
+    target_copy  BIGINT NOT NULL REFERENCES asset.copy(id)
+                 DEFERRABLE INITIALLY DEFERRED,
+    due_date     TIMESTAMP WITH TIME ZONE NOT NULL,
+    checkin_time TIMESTAMP WITH TIME ZONE,
+    source_circ  BIGINT NOT NULL REFERENCES action.circulation(id)
+                 ON DELETE SET NULL DEFERRABLE INITIALLY DEFERRED
+);
+
+CREATE OR REPLACE FUNCTION action.maintain_usr_circ_history() 
+    RETURNS TRIGGER AS $FUNK$
+DECLARE
+    cur_circ  BIGINT;
+    first_circ BIGINT;
+BEGIN                                                                          
+
+    -- Any retention value signifies history is enabled.
+    -- This assumes that clearing these values via external 
+    -- process deletes the action.usr_circ_history rows.
+    -- TODO: replace these settings w/ a single bool setting?
+    PERFORM 1 FROM actor.usr_setting 
+        WHERE usr = NEW.usr AND value IS NOT NULL AND name IN (
+            'history.circ.retention_age', 
+            'history.circ.retention_start'
+        );
+
+    IF NOT FOUND THEN
+        RETURN NEW;
+    END IF;
+
+    IF TG_OP = 'INSERT' AND NEW.parent_circ IS NULL THEN
+        -- Starting a new circulation.  Insert the history row.
+        INSERT INTO action.usr_circ_history 
+            (usr, xact_start, target_copy, due_date, source_circ)
+        VALUES (
+            NEW.usr, 
+            NEW.xact_start, 
+            NEW.target_copy, 
+            NEW.due_date, 
+            NEW.id
+        );
+
+        RETURN NEW;
+    END IF;
+
+    -- find the first and last circs in the circ chain 
+    -- for the currently modified circ.
+    FOR cur_circ IN SELECT id FROM action.circ_chain(NEW.id) LOOP
+        IF first_circ IS NULL THEN
+            first_circ := cur_circ;
+            CONTINUE;
+        END IF;
+        -- Allow the loop to continue so that at as the loop
+        -- completes cur_circ points to the final circulation.
+    END LOOP;
+
+    IF NEW.id <> cur_circ THEN
+        -- Modifying an intermediate circ.  Ignore it.
+        RETURN NEW;
+    END IF;
+
+    -- Update the due_date/checkin_time on the history row if the current 
+    -- circ is the last circ in the chain and an update is warranted.
+
+    UPDATE action.usr_circ_history 
+        SET 
+            due_date = NEW.due_date,
+            checkin_time = NEW.checkin_time
+        WHERE 
+            source_circ = first_circ 
+            AND (
+                due_date <> NEW.due_date OR
+                -- coalesce on a common value so we can <> compare NULL's
+                COALESCE(checkin_time, NEW.xact_start) <> 
+                    COALESCE(NEW.checkin_time, NEW.xact_start)
+            );
+
+    RETURN NEW;
+END;                                                                           
+$FUNK$ LANGUAGE PLPGSQL; 
+
+CREATE TRIGGER maintain_usr_circ_history_tgr 
+    AFTER INSERT OR UPDATE ON action.circulation 
+    FOR EACH ROW EXECUTE PROCEDURE action.maintain_usr_circ_history();
+
+COMMIT;
+