How do I delete the data from all my tables in ORACLE 10g - oracle10g

Question

I have an ORACLE schema containing hundreds of tables. I would like to delete the data from all the tables (but don't want to DROP the tables).
Is there an easy way to do this or do I have to write an SQL script that retrieves all the table names and runs the TRUNCATE command on each ?
I would like to delete the data using commands in an SQL-Plus session.

Answer 1

If you have any referential integrity constraints (foreign keys) then truncate won't work; you cannot truncate the parent table if any child tables exist, even if the children are empty.
The following PL/SQL should (it's untested, but I've run similar code in the past) iterate over the tables, disabling all the foreign keys, truncating them, then re-enabling all the foreign keys. If a table in another schema has an RI constraint against your table, this script will fail.
set serveroutput on size unlimited
declare
l_sql varchar2(2000);
l_debug number := 1; -- will output results if non-zero
-- will execute sql if 0
l_drop_user varchar2(30) := '' -- set the user whose tables you're dropping
begin
for i in (select table_name, constraint_name from dba_constraints
where owner = l_drop_user
and constraint_type = 'R'
and status = 'ENABLED')
loop
l_sql := 'alter table ' || l_drop_user || '.' || i.table_name ||
' disable constraint ' || i.constraint_name;
if l_debug = 0 then
execute immediate l_sql;
else
dbms_output.put_line(l_sql);
end if;
end loop;
for i in (select table_name from dba_tables
where owner = l_drop_user
minus
select view_name from dba_views
where owner = l_drop_user)
loop
l_sql := 'truncate table ' || l_drop_user || '.' || i.table_name ;
if l_debug = 0 then
execute immediate l_sql;
else
dbms_output.put_line(l_sql);
end if;
end loop;
for i in (select table_name, constraint_name from dba_constraints
where owner = l_drop_user
and constraint_type = 'R'
and status = 'DISABLED')
loop
l_sql := 'alter table ' || l_drop_user || '.' || i.table_name ||
' enable constraint ' || i.constraint_name;
if l_debug = 0 then
execute immediate l_sql;
else
dbms_output.put_line(l_sql);
end if;
end loop;
end;
/

Answer 2

Probably the easiest way is to export the schema without data, then drop an re-import it.

Answer 3

I was looking at this too.
Seems like you do need to go through all the table names.
Have you seen this? Seems to do the trick.

Answer 4

I had to do this recently and wrote a stored procedure which you can run via: exec sp_truncate;. Most of the code is based off this: answer on disabling constraints
CREATE OR REPLACE PROCEDURE sp_truncate AS
BEGIN
-- Disable all constraints
FOR c IN
(SELECT c.owner, c.table_name, c.constraint_name
FROM user_constraints c, user_tables t
WHERE c.table_name = t.table_name
AND c.status = 'ENABLED'
ORDER BY c.constraint_type DESC)
LOOP
DBMS_UTILITY.EXEC_DDL_STATEMENT('ALTER TABLE ' || c.owner || '.' || c.table_name || ' disable constraint ' || c.constraint_name);
DBMS_OUTPUT.PUT_LINE('Disabled constraints for table ' || c.table_name);
END LOOP;
-- Truncate data in all tables
FOR i IN (SELECT table_name FROM user_tables)
LOOP
EXECUTE IMMEDIATE 'TRUNCATE TABLE ' || i.table_name;
DBMS_OUTPUT.PUT_LINE('Truncated table ' || i.table_name);
END LOOP;
-- Enable all constraints
FOR c IN
(SELECT c.owner, c.table_name, c.constraint_name
FROM user_constraints c, user_tables t
WHERE c.table_name = t.table_name
AND c.status = 'DISABLED'
ORDER BY c.constraint_type)
LOOP
DBMS_UTILITY.EXEC_DDL_STATEMENT('ALTER TABLE ' || c.owner || '.' || c.table_name || ' enable constraint ' || c.constraint_name);
DBMS_OUTPUT.PUT_LINE('Enabled constraints for table ' || c.table_name);
END LOOP;
COMMIT;
END sp_truncate;
/

Answer 5

Putting the details from the OTN Discussion Forums: truncating multiple tables with single query thread into one SQL script gives the following which can be run in an SQL-Plus session:
SET SERVEROUTPUT ON
BEGIN
-- Disable constraints
DBMS_OUTPUT.PUT_LINE ('Disabling constraints');
FOR reg IN (SELECT uc.table_name, uc.constraint_name FROM user_constraints uc) LOOP
EXECUTE IMMEDIATE 'ALTER TABLE ' || reg.table_name || ' ' || 'DISABLE' ||
' CONSTRAINT ' || reg.constraint_name || ' CASCADE';
END LOOP;
-- Truncate tables
DBMS_OUTPUT.PUT_LINE ('Truncating tables');
FOR reg IN (SELECT table_name FROM user_tables) LOOP
EXECUTE IMMEDIATE 'TRUNCATE TABLE ' || reg.table_name;
END LOOP;
-- Enable constraints
DBMS_OUTPUT.PUT_LINE ('Enabling constraints');
FOR reg IN (SELECT uc.table_name, uc.constraint_name FROM user_constraints uc) LOOP
EXECUTE IMMEDIATE 'ALTER TABLE ' || reg.table_name || ' ' || 'ENABLE' ||
' CONSTRAINT ' || reg.constraint_name;
END LOOP;
END;
/