Hi Mr Tom,

I had gone through the concept of avoiding overlapping dates...it really helps me but in addition to that i want one extra check in that i.e in my scenario date_to can be null.

Suppose i already have :

date_from date_to
01.04.2004 10.04.2004
20.04.2004 ----->>date_to is null

Now in if anybody wants to insert

25.04.2004 30.04.2004 ---->>>Not allowed because these dates are greater that 20.4.2004

15.04.2004 17-04-2004 ---->>>Allowed because dates are less that 20.4.2004

18.4.2004 ---->>>Not allowed ,in this case date_to is mandatory and should be less than 20.4.2004


If i Summarize then if at any instance date_to is null then further records are not allowed which are greater than date_from(as in above 20.4.2004) but less than date_from records are allowed .If records are less than in that case date_to is mandatory.

Looking at this could you please help to sort it out.

Thanks