i want to create one temp table in procedure and use that table in that procedure only after finishing to execute that 'SP' then automatically delete that table so how can i do that one?
You can you the dynamic SQL
execute immediate 'create table my_table (/* cols here */)';
and at the end:
execute immediate 'drop table my_table';
Also worth mentioning, you can't compile the code while using the temp table directly as table is not present at compile time. You have to use dynamic SQL in order to use it.
You can use dynamic sql
Execute immediate 'create table...'
Then you can do your staf
After all all of them in same way you can drop table
execute immediate 'drop table....
Related
I have 50 databases.
All the table schema in all the databases are the same. If I have a new column to be added to one table, I will have to run 50 times to update in all databases. This is very difficult all the time.
Is there an editor for postgres where there is a way to execute a query in all databases?
Currently, I am using dbeaver. I have to change the connection all the time and execute the query. Please help.
Example: I had to alter a table by adding a column.
ALTER TABLE table-name ADD new-column-name column-definition;
It is very difficult to execute for 50 databases.
For executing this answer, you need to have dblink extension.
DO $$
DECLARE
i text;
BEGIN
FOR i in SELECT datname FROM pg_database
LOOP
EXECUTE 'select * from dblink(''host=localhost
user=postgres
password=postgres
dbname='||i||' port=5432'',''ALTER TABLE table-name ADD new-column-name column-definition'' ) tt(
updated text)'
END LOOP;
END $$
I have to create a plsql block which will add a new column on a table ( with dynamic Sql) and then it will insert some data in that new added column.
When I execute my block, I got a message that says that my column is not defined, even if it has been added before the insert statement.
Do you have any idea of what could be causing this problem?
It's like my insert statement doesn't know that the new column has been added.
If you add new column and update/insert data in the new column using dynamic SQL then it will work.
Example -
begin
execute immediate 'ALTER TABLE table_name ADD column_name column-definition';
execute immediate 'update table_name set column_name =''sample-data''';
COMMIT ;
end;
But, if you add new column using dynamic SQL and use static SQL to update/insert then it will throw error message.
Reason - The static SQL is validated before its execution.
Example -
begin
execute immediate 'ALTER TABLE table_name ADD column_name column-definition';
update table_name set column_name ='sample-data';
COMMIT ;
end;
I am new to Oracle Sql and facing an issue :
I want to create a temporary table inside procedure .
LIKE:
CREATE PROCEDURE P
AS
BEGIN
CREATE TEMPORARY TABLE A(ID int);
END P;
BUT THIS IS GIVING ME AN ERROR
How Can I Create a temporary table inside procedure.
I have seen other answers on stackoverflow but that doesn't answer my question properly
Can you please help me out ?
Why do you want to create a temporary table in a stored procedure in the first place?
It is relatively common to create temporary tables in other databases (SQL Server and MySQL, for example). It is very, very rare to do the same thing in Oracle. In almost every case where you are tempted to create a temporary table in Oracle, there is a better architectural approach. There is a thread over on the DBA stack that discusses alternatives to temporary tables and why they are not commonly needed in Oracle.
Programmatically, you can create objects using dynamic SQL
CREATE OR REPLACE PROCEDURE dont_do_this
AS
BEGIN
EXECUTE IMMEDIATE 'CREATE GLOBAL TEMPORARY TABLE a( id INTEGER )';
END;
If you create a temporary table dynamically, however, every reference to that table will also need to be via dynamic SQL-- you won't be able to write simple SELECT statements against the table. And the definition of a temporary table in Oracle is global so it is visible to every session. If you have two different sessions both trying to create the same table, the second session will get an error. If you expect the table to have a different definition in different sessions, you've got even more problems.
You could use Dynamic SQL with EXECUTE IMMEDIATE:
CREATE OR REPLACE
PROCEDURE p
AS
BEGIN
EXECUTE IMMEDIATE 'CREATE TEMPORARY TABLE A(id NUMBER)...etc';
END p;
Edit: Obviously you'll have to ensure your syntax is correct within the EXECUTE IMMEDIATE statement.
Hope it helps.
You must declare your procedure as:
create or replace PROCEDURE MYPROCEDURE AUTHID CURRENT_USER IS
script varchar(4000);
BEGIN
script:= 'CREATE GLOBAL TEMPORARY TABLE BNMCODIAGNOSTICASSOCIE_TEMP
ON COMMIT PRESERVE ROWS
as select ........';
EXECUTE IMMEDIATE script;
commit;
END;
I need a script which creates table or if it already exist drops it, and when recreates table. After some research I have found out that CREATE OR REPLACE TABLE in pl/sql doesn't exist. So I come up with this script :
DECLARE
does_not_exist EXCEPTION;
PRAGMA EXCEPTION_INIT (does_not_exist, -942);
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE foobar';
EXCEPTION
WHEN does_not_exist
THEN
NULL;
END;
/
CREATE TABLE foobar (c1 INT);
Is there any proper way to achieve this functionality?
You really shouldn't be doing this in PL/SQL, tables created at runtime would be indicative of a flaw in your data model. If you're really convinced you absolutely have to do this then investigate temporary tables first. Personally, I'd reassess whether it's necessary at all.
You seem to be going for the EAFP as opposed to LBYL approach, which is described in a few answers to this question. I would argue that this is unnecessary. A table is a fairly static beast, you can use the system view USER_TABLES to determine whether it exists before dropping it.
declare
l_ct number;
begin
-- Determine if the table exists.
select count(*) into l_ct
from user_tables
where table_name = 'THE_TABLE';
-- Drop the table if it exists.
if l_ct = 1 then
execute immediate 'drop table the_table';
end if;
-- Create the new table it either didn-t exist or
-- has been dropped so any exceptions are exceptional.
execute immediate 'create table the_table ( ... )';
end;
/
Using a global temporary table would seem to be a better option. However, if you insist on dropping and re-adding tables at runtime you could query one of the _TABLES views (i.e. USER_TABLES, DBA_TABLES, ALL_TABLES) to determine if the table exists, drop it if it does, then create it:
SELECT COUNT(*)
INTO nCount
FROM USER_TABLES
WHERE TABLE_NAME = 'FOOBAR';
IF nCount <> 0 THEN
EXECUTE IMMEDIATE 'DROP TABLE FOOBAR';
END IF;
EXECUTE IMMEDIATE 'CREATE TABLE FOOBAR(...)';
Share and enjoy.
I want to call create table/ alter table command from a procedure. Is it possible?
My requirement is to change the datatype of a column in all tables. So, I am just getting the column name from user_tab_cols. Now I want to create a temp table which requires create statement .. but i am unable to use that within a proc.
Can anyone please help me out?
I presume from the reference to USER_TAB_COLUMNS that this is Oracle. ALTER and CREATE statements are DDL, which we cannot execute directly in PL/SQL. However, there are a couple of ways around this restriction: EXECUTE IMMEDIATE and DBMS_UTILITY.EXEC_DDL(). I will use EXECUTE IMMEDIATE in the following example.
begin
for lrec in ( select table_name from user_tab_columns
where column_name = 'UNIVERSAL_COLUMN_NAME')
loop
execute immediate 'alter table '||lrec.table_name||
' modify UNIVERSAL_COLUMN_NAME varchar2(255)';
end loop;
end;
Note that the usual restrictions apply: the new datatype has to be compatible with the existing datatype (unless the column is empty), and things are trickier with some specilaized datatypes like CLOBs.
edit
I haven't addressed the CREATE TABLE statement. The principle is the same, it is just longer to type out. Besides, I am not entirely clear how it applies to your prior requirement to change the datatype of those columns.
you can generate the query as string and execute it with 'exec' keyword.