SQL: delete all the data from all available tables

Question

I am using oracle DB to maintain more than 30 tables, how can I delete all the data from all the tables? I only want to delete the data but not drop the tables.

Answer 1

There is no command 'ALTER TABLE XXX DISABLE ALL CONSTRAINTS'

I propose this;

BEGIN
  FOR c IN (SELECT table_name, constraint_name FROM user_constraints WHERE constraint_type = 'R')
  LOOP
    EXECUTE IMMEDIATE ('alter table ' || c.table_name || ' disable constraint ' || c.constraint_name);
  END LOOP;
  FOR c IN (SELECT table_name FROM user_tables)
  LOOP
    EXECUTE IMMEDIATE ('truncate table ' || c.table_name);
  END LOOP;
  FOR c IN (SELECT table_name, constraint_name FROM user_constraints WHERE constraint_type = 'R')
  LOOP
    EXECUTE IMMEDIATE ('alter table ' || c.table_name || ' enable constraint ' || c.constraint_name);
  END LOOP;
END;

Answer 2

To address the issue of constraints, something like this should work:

BEGIN

    FOR T in (SELECT table_name FROM user_tables) LOOP
      EXECUTE IMMEDIATE 'ALTER TABLE '||T.table_name||' DISABLE ALL CONSTRAINTS';
    END LOOP;

    FOR T in (SELECT table_name FROM user_tables) LOOP
      EXECUTE IMMEDIATE 'TRUNCATE TABLE '||T.table_name;
    END LOOP;

    FOR T in (SELECT table_name FROM user_tables) LOOP
      EXECUTE IMMEDIATE 'ALTER TABLE '||T.table_name||' ENABLE ALL CONSTRAINTS';
    END LOOP;
END;

Answer 3

Delete all the data from all tables in oracle

DECLARE
  str VARCHAR2(100);
BEGIN
  FOR i IN
  (SELECT object_name FROM user_objects WHERE object_type='TABLE'
  )
  LOOP
    str := 'Truncate table '|| i.object_name;
    EXECUTE IMMEDIATE str;
    DBMS_OUTPUT.PUT_LINE('table data deleted :' || i.object_name);
  END LOOP;
END;

For more info: http://www.oracleinformation.com/2014/10/delete-all-the-data-from-all-tables.html

Answer 4

Clone the schema and then drop the old tables?

Answer 5

A slight variation on Andomar's answer to truncate all tables for a specific user instead of only those of the current user:

SELECT 'TRUNCATE TABLE ' || owner || '.' || table_name || ';' FROM all_tables WHERE owner = 'user/schema'

Replace the user/schema bit above with the name of the user/schema (between the quotes) you are interested in.

Answer 6

these two line script are the best

EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL'
GO

EXEC sp_MSForEachTable 'DELETE FROM ?'
GO