Thanks, you helped me.

>Free Tables do not have field or row level rules. You can make the Valid() mehots of the date textbox in the grid return ! empty( this.Value )
>
>> In a form, I have a grid(grid1) which contains a free table(table1). The first field is date. After I set:
>>
>>thisform.grid1.readonly=.f.
>>select table1
>>append blank
>>
>>The user can input data to this free table. If he inputted an empty data to the date field, my VFP software will have problems. So I want to not allow the user to input an empty date. He must enter a date before he save the tabel or move the cursor to the other field in the table. How can I do that?
>>I have tried to make a database and add this table on it so that I can add ".not.empty" in the Field Validation. But I will have other problems if I use a database at this stage. I cannot find the Field Validation box in the Table Designer if my table is a free table but I can find it if my table is under a database. I don't know why.