A Lookup field is a read-only field that displays a value at runtime retrieved from another table/dataset using a key that you specify.
To define a Lookup field, it is necessary to set the name of the existing key field to search on, the name of the key field from the lookup dataset and the field from the lookup dataset whose value it should display.
For example, suppose we have two tables:
and we need to define the lookup field CategoryName in the Products table.
In this case, the lookup datatable will be the
Categories table, the existing field to search on is
Products.CategoryID, the key field is
Categories.CategoryID, and the field whose value should be displayed is