ORCALE清除全部表数据，保留表结构

begin
for c in(select t.constraint_name, t.table_name
  from USER_CONSTRAINTS t
where t.constraint_type = 'R') loop
EXECUTE IMMEDIATE 'alter table  '  ||c.table_name|| '  DISABLE CONSTRAINT '||c.constraint_name;
end loop;
for c1 in(select table_name from user_tables) loop
  EXECUTE IMMEDIATE 'truncate table '||c1.table_name;
end loop;
for c2 in(select t.constraint_name, t.table_name
  from USER_CONSTRAINTS t
where t.constraint_type = 'R') loop
EXECUTE IMMEDIATE 'alter table  '  ||c2.table_name|| '  ENABLE CONSTRAINT '||c2.constraint_name;
end loop;
end;