I need to drop a table only if the table exist, can do it using plsql block
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE <table_name>;
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -942 THEN
RAISE;
END IF;
END
But in my case the table name has sysdate (02062017) eg table001_02072017 and i need to delete all such tables with sysdate-1.
How can i do so?
You can find the table with the given pattern from user_tables dictionary table and loop on the result to drop each one by one.
begin
for t in (select table_name from user_tables
where table_name like '%\_'||to_char(sysdate-1,'mmddyyyy') escape '\')
loop
execute immediate 'drop table ' || t.table_name;
end loop;
exception
/* Handle your exceptions here. */
end;
/
Using WHEN OTHERS in your exception handling is discouraged. You should explicitly handle the errors.
Dynamic sql will help you here just use
execute immediate 'drop table ' || table_name;
inside your procedure
Related
I created procedure in oracle that drops my table and creates same table from my view. But I have some problems with running this procedure. First step with drop table works but copying it doesn't work.
It this a good procedure ?
create or replace PROCEDURE transfer_table (table_name IN VARCHAR2,tableFrom IN VARCHAR2) IS
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE ' || table_name;
EXECUTE IMMEDIATE 'CREATE TABLE ' || table_name || ' AS SELECT * FROM ' || tableFrom;
commit;
END transfer_table;
Next I click on this procedure and change the variable then view and click ok, but only the first step of dropping the table is working. What am I doing wrong ?
I think you need to catch the error if the table you are creating doesn't exist.
create or replace PROCEDURE transfer_table (table_name IN VARCHAR2,tableFrom IN VARCHAR2) IS
BEGIN
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE ' || table_name;
EXCEPTION WHEN OTHERS THEN
NULL;
END;
EXECUTE IMMEDIATE 'CREATE TABLE ' || table_name || ' AS SELECT * FROM ' || tableFrom;
commit;
END transfer_table;
I'm trying to create a procedure that given a table name, it will create a sequence and auto incrementing trigger, all using variables based on the table name.
Code :
CREATE OR REPLACE procedure CREATE_SEQUENTIAL_TR(table_name VARCHAR)
is -- Tried using declare but it wouldn't accept
coluna_cod varchar(100 char);
begin
--Finding the cod column name for this table first
--They start with "PK_CD"
select
COLUMN_NAME
into
coluna_cod
from
ALL_TAB_COLUMNS
where
TABLE_NAME=table_name
and COLUMN_NAME like "PK_CD%";
--Creating the sequence obj
drop sequence "cod" || table_name;
create sequence "cod" || table_name;
--Now creating the trigger
create or replace trigger "cod" || table_name || "tr"
before
UPDATE or INSERT on table_name
for each row
declare
cod number := coluna_cod;
tr_name varchar(100 char) := "cod" || table_name
begin
if UPDATING then
if :new.cod != :old.cod then
:new.cod := :old.cod;
end if;
else -- inserting
:new.cod := tr_name.nextval();
end if;
end;
end;
The complexity of this ended up quite out of the scope of my knowledge.
At the moment it is giving an error on drop sequence "cod" || table_name (Unexpected DROP symbol found) but I'm sure I have made other errors.
Can someone help me figure this logic out?
You can't put DDL statements (like drop or create or alter) directly inside a PL/SQL block. If you want to do DDL inside PL/SQL, you can do an execute immediate:
declare
begin
drop sequence X; -- error
execute immediate 'drop sequence X'; -- works fine
end;
/
Can some one please guide me what's wrong with this query? In SQL Server we just check the presence of the Object_ID of a table to drop it and re-create it. I am new to Oracle and wrote this query:
declare Table_exists INTEGER;
BEGIN
Select count(*) into Table_exists from sys.all_tables where table_name='TABLENAME1';
EXCEPTION
WHEN NO_DATA_FOUND
THEN
Table_Exists :=0;
if(table_exists)=1
Then
Execute Immediate 'Drop Table TABLENAME1;'
'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('Table Dropped and Re-Created!');
Else
Execute Immediate 'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('New Table Created!');
END IF;
END;
I get the output - ANONYMOUS BLOCK COMPLETED, but the table is not created. The table was previously existing, so I dropped it to check if the PL/SQL is actually creating the table, but NO. What is wrong here? What am I missing? Please guide.
When you are using all_tables filter the results for your
schema by adding where owner = 'your_schema'
or use sys.user_tables
ALL_TABLES describes the relational tables accessible to the current user
USER_TABLES describes the relational tables owned by the current user.
When use execute_emmidiate remove the ; from the query;
Modified query;
DECLARE
Table_exists INTEGER;
BEGIN
Select count(*) into Table_exists from sys.user_tables where table_name='TABLENAME1';
--or
--Select count(*) into Table_exists from sys.all_tables
--where table_name='TABLENAME1' and owner = 'your_DB';
if table_exists = 1 Then
Execute Immediate 'Drop Table TABLENAME1';
Execute Immediate 'Create Table TABLENAME1(num number)';
DBMS_OUTPUT.PUT_LINE('Table Dropped and Re-Created!');
Else
Execute Immediate 'Create Table TABLENAME1(num number)';
DBMS_OUTPUT.PUT_LINE('New Table Created!');
END IF;
END;
First note:
Select count(*) into Table_exists
from sys.all_tables
where table_name = 'TABLENAME1';
will always return one row. You don't need the exception handling.
My best guess is that you have more than one table called TABLENAME1. Run this query to find out:
Select *
from sys.all_tables
where table_name = 'TABLENAME1';
Oracle stores tables from all owners that you can access. You might also want to check OWNER_NAME in the where clause.
However, you seem to understand exception handling. So, just drop the table, ignore any errors, and then recreate the table.
The EXCEPTION clause lasts till the next END and not just the next statement. If you want to continue after catching the exception you need to add an additional BEGIN/END:
declare
Table_exists INTEGER;
BEGIN
BEGIN
Select count(*) into Table_exists from sys.all_tables where table_name='TABLENAME1';
EXCEPTION
WHEN NO_DATA_FOUND THEN
Table_Exists :=0;
END;
if(table_exists)=1 Then
Execute Immediate 'Drop Table TABLENAME1;'
Execute Immediate 'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('Table Dropped and Re-Created!');
Else
Execute Immediate 'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('New Table Created!');
END IF;
END;
As pointed out by Gordon, the EXCEPTION clause is not really needed in this case since count(*) will always return one row. So the following is sufficient:
declare
Table_exists INTEGER;
BEGIN
Select count(*) into Table_exists from sys.all_tables where table_name='TABLENAME1';
if(table_exists)=1 Then
Execute Immediate 'Drop Table TABLENAME1;'
Execute Immediate 'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('Table Dropped and Re-Created!');
Else
Execute Immediate 'Create Table TABLENAME1;';
DBMS_OUTPUT.PUT_LINE('New Table Created!');
END IF;
END;
I have been wrapping my "drop tables" in the following block to avoid raising 942 errors if the table doesn't exist:
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE1';
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE2';
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE3';
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE4';
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE5';
EXECUTE IMMEDIATE 'DROP TABLE MY_TABLE6';
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -942 THEN RAISE;
END IF;
END;
This works great most of the of time. However, intermittently it will seem to refuse to drop this table or that. It's not always the same table, and it doesn't always happen in any particular set of queries. It just happens...sometimes...for reasons I can't explain, hence my asking this question.
Has anyone else experienced this, and if so, what did you do about it?
Most likely cause I can think of is the table is locked (outstanding commits) in another session. What error is reported?
Also there is a problem with your script - if TABLE1 has already been dropped, TABLE2...6 won't get dropped because your first DROP will jump to the exception.
Better to do this:
DECLARE
PROCEDURE drp ( tName IN VARCHAR2 ) IS
BEGIN
EXECUTE IMMEDIATE 'drop table ' || tName;
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -942 THEN RAISE;
END IF;
END;
BEGIN
drp ( 'TABLE1' );
drp ( 'TABLE2' );
drp ( 'TABLE3' );
-- etc
END;
I want to drop certain tables in a tablespace that has common name appended to end of each table for an example:
TABLE1_NAME1_COMMON
TABLE2_NAME2_COMMON
TABLE3_NAME3_COMMON
I heard about Oracle functions but I'm not familiar much with those so I'm expecting some helping hand.
Thanks.
If you're completely sure what you're doing, ie, if you're sure that you don't accidentally drop a table that you don't want to drop, you can do a:
set serveroutput on size 1000000
begin
for r in (
select table_name
from user_tables
where table_name like '%\_COMMON' escape '\')
loop
execute immediate 'drop table ' || r.table_name;
end loop;
exception when others then
dbms_output.put_line(sqlerrm);
end;
/
Edit:
Changed Now selecting from user_tables instead of dba_tables as it seems more safe to do.
Added set serveroutput on in order for dbms_output.put_line to be printed
Added begin .. exception .. end in order for errors to be shown.
You could do that in a procedure, but it might be better to just select those DROP-statements, review them and execute them manually:
SELECT 'DROP TABLE ' || table_name || ';'
FROM user_tables
WHERE table_name LIKE '%\_COMMON' ESCAPE '\';
would return
DROP TABLE TABLE1_NAME1_COMMON;
DROP TABLE TABLE2_NAME2_COMMON;
DROP TABLE TABLE3_NAME3_COMMON;
to identify them you can use:
SELECT * FROM user_tables WHERE tablespace_name='MySpace' AND table_name like '%COMMON';
You could then either, derive your DROP statements using a SELECT. Or you could write a PL/SQL function to loop through the "Common Tables" and DROP them using EXECUTE IMMEDIATE.
I would make sure you are 100% sure in the selections first however.