Create function to iterate over stock items

SQL/plpgsql/create_supply_every_stock.sql

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+CREATE OR REPLACE FUNCTION supply_every_stock(amount INTEGER) RETURNS void AS
+$$
+DECLARE
+    stoCursor CURSOR IS SELECT sto_quantity FROM Stock FOR UPDATE;
+    stoQuantity Stock.sto_quantity%TYPE;
+BEGIN
+    RAISE NOTICE 'Iterate on existing stocks only';
+
+    -- Iterate on storage
+    OPEN stoCursor;
+    LOOP
+        FETCH stoCursor INTO stoQuantity;
+        EXIT WHEN stoQuantity IS NULL;
+
+        RAISE NOTICE 'Supply %', amount;
+    END LOOP;
+    CLOSE stoCursor;
+    RAISE NOTICE 'End';
+END;
+$$
+LANGUAGE plpgsql;