How to truncate all user tables?

Question

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

Answer 1

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 2

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;