>this is what i have done :
>
>function majtable
> replace DATECUR with date()
>endfunc
>
>in the table designer, i put majtable() on the validation rule.
>the resulte is that, when i append or edit a record all records take the same value in the DATECUR field.
>
>to correct that, i put that code on the update trigger.
>but after updated an error appears that the table in read only.
>
>what is the solution ?

Try to add the table rule programmatically using NOVALIDATE option to not update the existing records.

ALTER TABLE myTable SET CHECK 'MajTable' NOVALIDATE