Creating a new Lookup Column
Lookup columns can be created, if there is a many-to-one relation between tables. These columns can be added to the Details table to represent a specific data from a related Master table (for example, the Projects table may need to contain the Client Company, Client Phone, Client E-mail from the related Clients table).
Using one relation you can add as many lookup columns as you need.
Usually, when a reference column of Many-To-One cardinality is created and a Proxy column is chosen in the reference column settings, the lookup column displaying Proxy column values is added to a table automatically.
The simplest way to add a lookup column to a related table is the following:
Click the Setup link in the top right corner of the window
Select a table you need.
From the setup menu select Column > Create a new lookup column.
In the References section click the Add Lookup button near a necessary relation:
The Lookup column form will be displayed:
Please note, if a lookup refers to a column of the File Attachment type and the Display As Link option is unchecked in the lookup settings, a user, who clicks on such lookup, will be redirected to the attached document or image. Moreover, if an image (or a signature) is attached, this image (or signature) will be shown as a lookup value. In case the Display As Link checkbox is activated, only the link referring to the master record will be displayed as a lookup value. After clicking on such link, the master record keeping the attachment will be opened.