Limit list entry according to number in group

Question

I have a very simple list, 2 columns actually. "Name" and "Table".

Its for users to reserve a table at an event. "Name" is free text and "Table" is a selection drop down

There are obviously a limited number of seats on each table and I would like to limit the reservation to 10 per table. Trouble is I don't know how! :-)

Answer 1

Hmm just thinking, can you do the Name as an appendable multi-line text field and somehow check it with a piece of Javascript, if it already has 10 rows, don't let it be submitted.

Answer 2

NewForm.aspx in a SharePoint list has a PreSaveAction() javascript method that can be extended or overridden. For example in your case, on the new item form if a user has selected Table 1 and tried to save then your PreSaveAction() can query the list to count the number of times table 1 have been selected. if the number is equal to 10 then item will not be saved and you can display relevant message to the user that the "Table is fully booked"

function PreSaveAction() {
return checkBookingForTable();
}

function checkBookingForTable()
{
query sharepoint list using REST or CSOM if (bookingCount<10){ retrun true}; else return false;

}