Tables to block a duplicate entry and display message

[emandel]

In my DB I have an Events Table, a Participants table, and a attendance table. The attendance table is the junction table that connects the other two (many to many).
So in the attendance tale, I record which participant ID came to which event ID.

Is there any way that I can block a duplicate entry, and have access tell the operator "oops - you already have that entry".

Thank you for your patience

[ADezii]

In my DB I have an Events Table, a Participants table, and a attendance table. The attendance table is the junction table that connects the other two (many to many).
So in the attendance tale, I record which participant ID came to which event ID.

Is there any way that I can block a duplicate entry, and have access tell the operator "oops - you already have that entry".

Thank you for your patience

A Composite, Primary Key consisting of the Participant ID and the Event ID
should do the trick. This will ensure that no participant can attend the specific
event more than once.

[emandel]

A Composite, Primary Key consisting of the Participant ID and the Event ID
should do the trick. This will ensure that no participant can attend the specific
event more than once.

That was easy! Thank you!

[ADezii]

That was easy! Thank you!

Glad to be of assistance.