How to exceute a query stored in dictionary table into a CURSOR? - sql

Question

I’ve a table named QUERIES_DICTIONNARY with 2 columns (ID, SQL_QUERY) the first column is NUMBER and the second column is a Varchar represent an SQL query.
CREATE TABLE "QUERIES_DICTIONNARY"
(
"ID" NUMBER(10,0) NOT NULL ENABLE,
"SQL_QUERY" NVARCHAR2(2000) NOT NULL ENABLE
)
I want to create a stored procedure with 2 parameters (P_KEY, P_RESULTS_CURSOR) where the P_KEY is the ID of my table, and the P_RESULT_CURSOR where i execute my SQL query of the record having ID = P_KEY.
CREATE OR REPLACE PROCEDURE GET_STATISTICS_RESULTS
(
P_KEY IN NUMBER,
P_RESULTS_CURSOR OUT SYS_REFCURSOR
)
In my stored procedure I get the record where the ID = P_KEY
Once I’ve the record I want to execute the the associated query using EXECUTE IMMEDIATE into the P_RESULTS_CURSOR.
CREATE OR REPLACE PROCEDURE GET_STATISTICS_RESULTS
(
P_KEY IN NUMBER
P_RESULTS_CURSOR OUT SYS_REFCURSOR
) AS
BEGIN
---- Get the record
-- SELECT SQL_QUERY FROM QUERIES_DICTIONNARY WHERE ID = P_KEY;
---- Then Execute the query
-- OPEN P_RESULTS_CURSOR FOR ?
END GET_STATISTICS_RESULTS;
How can I do this approach in one Stored procedure please?

Answer 1

There is two ways: simple and not so simple. Simple way is:
CREATE OR REPLACE PROCEDURE GET_STATISTICS_RESULTS
(
P_KEY IN NUMBER;
P_RESULTS_CURSOR OUT SYS_REFCURSOR;
) AS
cursor_text QUERIES_DICTIONNARY.SQL_QUERY%TYPE;
BEGIN
---- Get the record
SELECT SQL_QUERY
INTO cursor_text
FROM QUERIES_DICTIONNARY WHERE ID = P_KEY;
---- Then Execute the query
OPEN P_RESULTS_CURSOR FOR cursor_text;
END GET_STATISTICS_RESULTS;
Not so simple way - using DBMS_SQL package. You can see example in documentation. It will be quite complicated decision.

Answer 2

CREATE OR REPLACE PROCEDURE GET_STATISTICS_RESULTS
(
P_KEY IN NUMBER
P_RESULTS_CURSOR OUT SYS_REFCURSOR
) AS
l_s "QUERIES_DICTIONNARY"."SQL_QUERY"%TYPE;
BEGIN
---- Get the record
SELECT SQL_QUERY into l_s FROM QUERIES_DICTIONNARY WHERE ID = P_KEY;
---- Then Execute the query
OPEN P_RESULTS_CURSOR FOR l_s;
END GET_STATISTICS_RESULTS;
PLS-00382 appears because of NVARCHAR2 column. You may try to cast nvarchar2 to varchar2:
l_s VARCHAR2(4000);
...
SELECT CAST(SQL_QUERY AS VARCHAR2(4000)) into l_s FROM QUERIES_DICTIONNARY WHERE ID = P_KEY;
...
But you may lose some data.