start work on rolling forward account balances

schema/triggers/bal_insert.sql

@@ -0,0 +1,41 @@
+---------------------------handle new gl lines----------------------------------------
+
+CREATE OR REPLACE FUNCTION evt.bal_insert() RETURNS trigger
+    LANGUAGE plpgsql
+    AS 
+    $func$
+    BEGIN
+        WITH
+        --incoming new accounts and any other periods used for the same accounts
+        rng AS (
+            --for each item determine if a gap exists between new an previous period (if any)
+            SELECT
+                ins.acct
+                ,ins.fspr
+                ,lower(f.dur) dur
+                ,max(lower(bp.dur)) maxp
+                ,min(lower(bp.dur)) minp
+            FROM
+                evt.bal ins
+                INNER JOIN evt.fspr f ON
+                    f.id = ins.fspr
+                LEFT OUTER JOIN evt.bal b ON
+                    b.acct = ins.acct
+                LEFT OUTER JOIN evt.fspr bp ON
+                    bp.id = b.fspr
+            WHERE ins.fspr = '2018.11'
+            GROUP BY
+                ins.acct
+                ,ins.fspr
+                ,f.dur
+        )
+        select
+        RETURN NULL;
+    END;
+    $func$;
+
+CREATE TRIGGER bal_insert 
+    AFTER INSERT ON evt.bal
+    REFERENCING NEW TABLE AS ins 
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE evt.bal_insert();