selecting data only once to avoid duplicating

[wannabeateacher]

How can I get a adtabase to recognise that a piece of data has already
been "used" in connection with another piece of data in another field.
My database is focussing on timetabling and I cannot have a person in
2 places at once.
Thankyou

[storrboy]

On Feb 22, 1:55 pm, "wannabeateacher" <[e-mail]>
wrote:

How can I get a adtabase to recognise that a piece of data has already
been "used" in connection with another piece of data in another field.
My database is focussing on timetabling and I cannot have a person in
2 places at once.
Thankyou

There are many ways, but your explanation is too vague to provide
useful advice.
When does the check need to be done, in a form, query, table - on
save, open, change of record?

[wannabeateacher]

On 22 Feb, 19:30, "storrboy" <[e-mail]:

On Feb 22, 1:55 pm, "wannabeateacher" <[e-mail]>
wrote:

How can I get a adtabase to recognise that a piece of data has already
been "used" in connection with another piece of data in another field.
My database is focussing on timetabling and I cannot have a person in
2 places at once.
Thankyou

There are many ways, but your explanation is too vague to provide
useful advice.
When does the check need to be done, in a form, query, table - on
save, open, change of record?

It would be at change of record I think because when a person is
deployed for one students lesson (my database is in a school), the
timetabler will go on to deploy for the next lesson and therefore that
person cannot be used for any other student during that time slot.