Datawarehousing Automation using stored procedure - sql

Question

I am trying to code a procedure where i can validate all the records are moved from source to target provided there is no transformation logic involved in between for that particular column. My approach is to take the group by count of source column and target column and match their count. If the count is 0 then all the records are matched for that particular column to the target table.
Further a minus from the 2 data group by count will provide the missing data.
Can any one help me further on this.
Stored procedure :
create or replace
PROCEDURE MOVE_CHECK
(SCHEMA_SOURCE IN VARCHAR2,SCHEMA_TARGET IN VARCHAR2, TABLE_SOURCE IN VARCHAR2, TABLE_TARGET IN VARCHAR2, COLUMN_SOURCE IN VARCHAR2,
COLUMN_TARGET IN VARCHAR2)
AS
A varchar2 (30);
B varchar2 (30);
C varchar2 (30);
D varchar2 (30);
E varchar2 (30);
F varchar2 (30);
COUNT_SOURCE number(38);
TEMP_1 VARCHAR2(500);
TEMP_2 VARCHAR2(500);
TEMP_3 VARCHAR2(500);
TEMP_4 VARCHAR2(500);
COUNT_QUERY number(38);
BEGIN
A:=SCHEMA_SOURCE;
B:=SCHEMA_TARGET;
C:=TABLE_SOURCE;
D:=TABLE_TARGET;
E:=COLUMN_SOURCE;
F:=COLUMN_TARGET;
-- checking the count of the source records
TEMP_1 :='select count ( '|| E ||' ) from ' || C;
EXECUTE IMMEDIATE TEMP_1 INTO COUNT_SOURCE;
DBMS_OUTPUT.PUT_LINE ('source_count:'||Count_source);
TEMP_2 :='CREATE GLOBAL TEMPORARY TABLE SET_SOURCE AS (SELECT COUNT(1) AS COUNT_SOURCE, '|| E ||' from ' || C || ' GROUP BY ' || E||' )';
EXECUTE IMMEDIATE TEMP_2;
TEMP_3 :='CREATE GLOBAL TEMPORARY TABLE SET_TARGET AS (SELECT COUNT(1) AS COUNT_TARGET, ' || F||'FROM '||D||' GROUP BY ' ||D ||' )';
EXECUTE IMMEDIATE TEMP_3;
TEMP_4:= 'SELECT COUNT(1) FROM SET_SOURCE INTERSECT SET_TARGET ';
EXECUTE IMMEDIATE TEMP_4 INTO COUNT_QUERY;
DBMS_OUTPUT.PUT_LINE ('OUTPUT:'||COUNT_QUERY);
IF COUNT_QUERY <> 0
THEN DBMS_OUTPUT.PUT_LINE ('PLEASE CHECK');
ELSE DBMS_OUTPUT.PUT_LINE ('DONE- NO MISMATCH');
END IF;
END MOVE_CHECK;
I am unable to run execute Temp_2,Temp_3,Temp_4
Error:
ORA-00955: name is already used by an existing object
ORA-06512: at "YDSCST.MOVE_CHECK", line 35
ORA-06512: at line 16
source_count:7
Process exited.

Answer 1

It generally helps if you print out the dynamic SQL and try to run it manually; it can make syntax errors much easier to spot. In this case if you called the original procedure for the DUAL table you'd see:
CREATE GLOBAL TEMPORARY TABLE SET_SOURCE AS (SELECT COUNT(1), DUMMY )
from DUAL GROUP BY DUMMY )
You'd then get the same ORA-00923 if you ran that, and it suggests the problem might be before the from. And looking at the code it's clear that there was an extra closing parenthesis after the column name. But you spotted that yourself and have now moved on to the next error.
The next error after that should be ORA-00998: must name this expression with a column alias, because you haven't specified what the temporary table's columns should be called. You can do that in the select or in the create:
TEMP_2 :='CREATE GLOBAL TEMPORARY TABLE SET_SOURCE (ROW_COUNT, COLUMN_NAME) '
|| 'AS (SELECT COUNT(1), ' || E || ' from ' || C || ' GROUP BY ' || E || ')';
But you seem to have found and fixed that yourself too as you're now getting an ORA-06502, which is because your TEMP variables are smaller than your query string now needs to be. But you've also fixed that yourself now, making them 500 characters instead of 100.
Your TEMP_3 is missing a space before its from; the value of F is currently concatenated to that directly, making that an invalid statement. And the group by is using D (table name) instead of F (column name)
TEMP_3 :='CREATE GLOBAL TEMPORARY TABLE SET_TARGET (ROW_COUNT, COLUMN_NAME) '
|| 'AS (SELECT COUNT(1), ' || F || ' FROM ' || D || ' GROUP BY ' || F ||' )';
That would be more obvious if you were using the procedure argument names instead of meaningless (and pointless) local variables.
Creating global temporary tables, or any structure, within a procedure is generally not a good idea. The second time you call this they will already exist and it will error on that. If you really need them at all, you should create the temporary tables once outside the procedure as a separate task, and just populate them inside the procedure.