Creating tables in pl/sql block

Question

I have the following piece of code that I execute in sqlplusw as @c:\process.sql
On running @c:\process.sql, an input is provided as prompted. There is a
declare and begin that processes some code. What I am looking for is -- Is there
a way that I can check the all_tables view for the following 3 tables :
TABLE1, TABLE2, TABLE3. Only on finding these tables, this
anonymous sql (that is inside starting from declare ... should execute).
If these tables are not found, I want to attempt creating the tables. If the attempt
was successful, then process. If creating tables attempt fails, exit with a dbms_output.put_line message and don't process
anything....
Can this be done ? If so, any hints would be great.....
Thanks
ACCEPT input_ssn prompt 'Enter SSN :'
SET feedback off
SET serveroutput on
SET echo off
SET term off
SET heading off
SET pagesize 0
SET linesize 10000
SET verify off
undefne sdate input_ssn
COL sdate new_value sdate
COL input_ssn new_value input_ssn
SELECT TO_CHAR (SYSDATE, 'YYYYMMDD') sdate
FROM DUAL;
SPOOL C:\SCRUB_DATA_&&sdate._&&input_ssn..TXT
SELECT 'REPORT GENERATED ON : ' || SYSDATE
FROM DUAL;
ALTER TRIGGER TRIG1 DISABLE;
DECLARE
BEGIN
FOR i IN .........
LOOP
END LOOP;
BEGIN
SELECT ..........
EXCEPTION
WHEN NO_DATA_FOUND
THEN
NULL;
END;
UPDATE ...........
FOR i IN .....
LOOP
UPDATE ....
BEGIN
SELECT ...
EXCEPTION
WHEN NO_DATA_FOUND
THEN
NULL;
END;
UPDATE ...
BEGIN
SELECT ....
EXCEPTION
WHEN NO_DATA_FOUND
THEN
NULL;
END;
UPDATE ...
END LOOP;
EXCEPTION
WHEN NO_DATA_FOUND
THEN
     NULL;
WHEN OTHERS
THEN
ecode := SQLCODE;
emesg := SQLERRM;
DBMS_OUTPUT.put_line ('Error code is : '||' - '|| ecode);
DBMS_OUTPUT.put_line ('Error message is :' || ' - ' || emesg);
END;
COMMIT ;
ALTER TRIGGER TRIG1 ENABLE;
SET term on
SET HEADING on
SELECT 'Processing complete for ' || '&&input_ssn'
FROM DUAL;
SPOOL off;
SET verify on
SET feedback on
----------------------------------------------------------

Answer 1

This is what I am doing :
ACCEPT input_ssn prompt 'Enter SSN :'
SET feedback on
SET serveroutput on
SET echo on
SET term on
SET heading on
SET pagesize 0
SET linesize 10000
SET verify on
undefne sdate input_ssn
COL sdate new_value sdate
COL input_ssn new_value input_ssn
SELECT TO_CHAR (SYSDATE, 'YYYYMMDD') sdate
FROM DUAL;
SPOOL C:\TEMP_DATA_&&sdate._&&input_ssn..TXT
ALTER TRIGGER TRIG1 DISABLE;
DECLARE
v_postal cheque.postal%TYPE;
v_count NUMBER;
l_tabexist NUMBER;
BEGIN
DBMS_OUTPUT.PUT_LINE('HELLO THERE');
     BEGIN
          DBMS_OUTPUT.PUT_LINE('HI THERE');
          SELECT 1 INTO l_tabexist FROM all_tables
               WHERE table_name = 'TABLE1_TEMP' AND owner='HARPER';
     EXCEPTION
          WHEN NO_DATA_FOUND THEN
               EXECUTE IMMEDIATE 'CREATE TABLE TABLE1_TEMP AS SELECT * FROM TABLE1 WHERE 1=2';
               EXECUTE IMMEDIATE 'ALTER TABLE TABLE1_TEMP ADD(TEMP_STATUS VARCHAR2(1))';
     END;
     BEGIN
               SELECT 1 INTO l_tabexist FROM all_tables
                    WHERE table_name = 'TABLE2_TEMP' AND owner='HARPER';
          EXCEPTION
               WHEN NO_DATA_FOUND THEN
                    EXECUTE IMMEDIATE 'CREATE TABLE TABLE2_TEMP AS SELECT * FROM TABLE2 WHERE 1=2';
                    EXECUTE IMMEDIATE 'ALTER TABLE TABLE2_TEMP ADD(TEMP_STATUS VARCHAR2(1))';
     END;
BEGIN
<my code that uses TABLE1_TEMP and TABLE2_TEMP supposed to be created above>
EXCEPTION
WHEN NO_DATA_FOUND
THEN
DBMS_OUTPUT.put_line ('No Data Found Exception encountered');
END;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.Put_Line('Something bad happened');
RAISE;
END;
COMMIT ;
ALTER TRIGGER TRIG1 ENABLE;
SET term on
SET HEADING on
SPOOL off;
SET verify on
SET feedback on
What is happening here is that until ALTER TRIGGER DISABLE, things are fine.
Then, it tries to process <my code> and cries saying 'Table or view not found'. Finally it enables the trigger back.
It is not even displaying either the 'HELLO THERE' or 'HI THERE' - which I suppose is the first thing it should have done.
Thanks