How to truncate all user tables?

Question

How can I truncate all user table in oracle? I have problem with tables constraints.

Answer 1

No need for variables

begin
  for r in (select table_name from user_tables) loop
    execute immediate 'truncate table ' || r.table_name;
  end loop;
end;

Regards K

Answer 2

declare

begin

for c1 in (select table_name, constraint_name from user_constraints) loop
    begin
        execute immediate ('alter table '||c1.table_name||' disable constraint '||c1.constraint_name);
    end;
end loop;

for t1 in (select table_name from user_tables) loop
    begin
        execute immediate ('truncate table '||t1.table_name);
    end;
end loop;

for c2 in (select table_name, constraint_name from user_constraints) loop
    begin
        execute immediate ('alter table '||c2.table_name||' enable constraint '||c2.constraint_name);
    end;
end loop;

end;
/

Answer 3

You can output, then execute the one you like:

set serveroutput on;

begin

for r in (select table_name from user_tables) loop

    dbms_output.put_line('truncate table ' || r.table_name);

  end loop;

end;

Answer 4

Improved the above script in case you can't remove the constraint because dependencies exist (in the form of foreign keys that are dependent on this constraint - ORA-02297.) and by printing all (disable, truncate and enable) statements.

set serveroutput on;

declare

begin

for c1 in (select y1.table_name, y1.constraint_name from user_constraints y1, user_tables x1 where x1.table_name = y1.table_name order by y1.r_constraint_name nulls last) loop
    begin
        dbms_output.put_line('alter table '||c1.table_name||' disable constraint '||c1.constraint_name || ';');
        execute immediate  ('alter table '||c1.table_name||' disable constraint '||c1.constraint_name);
    end;
end loop;

for t1 in (select table_name from user_tables) loop
    begin
        dbms_output.put_line('truncate table '||t1.table_name || ';');    
        execute immediate ('truncate table '||t1.table_name);
    end;
end loop;

for c2 in (select y2.table_name, y2.constraint_name from user_constraints y2, user_tables x2 where x2.table_name = y2.table_name order by y2.r_constraint_name nulls first) loop
    begin
        dbms_output.put_line('alter table '||c2.table_name||' enable constraint '||c2.constraint_name || ';');        
        execute immediate ('alter table '||c2.table_name||' enable constraint '||c2.constraint_name);
    end;
end loop;

end;

Answer 5

Improvement in case you have special constraints which make above script fail:

set serveroutput on;

declare

begin

for c1 in (select y.table_name, y.constraint_name from user_constraints y, user_tables x where x.table_name = y.table_name) loop
    begin
        dbms_output.put_line('alter table '||c1.table_name||' disable constraint '||c1.constraint_name || ';');
        execute immediate  ('alter table '||c1.table_name||' disable constraint '||c1.constraint_name);
    end;
end loop;

for t1 in (select table_name from user_tables) loop
    begin
        execute immediate ('truncate table '||t1.table_name);
    end;
end loop;

for c2 in (select table_name, constraint_name from user_constraints) loop
    begin
        execute immediate ('alter table '||c2.table_name||' enable constraint '||c2.constraint_name);
    end;
end loop;

end;
/