>thank you very much,
>
>but i think in this way i have huge data , effected to system speed
Then, I suggest you make an estimate: When will approximately 10% of your records be deleted? This may be after one week, or after several years, depending on the table.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)