Retrieve value in a form from another table in view only mode

[yvesf]

I have got 2 tables : tasks and patient.
In the patient, I have the firstname, lastname and date of birthday.
In the task form I have a lookup field which makes a search to the patient name and firstname but also date of birthday. I don't want to save dob in the task table, I would like to have a dynamic view of the dob without saving this information in the task table. If I use the input type, I will have to create a input field dob in the task table which is I want to avoid as much as possible. Another alternative would be to use the display object which will search in the database without saving it in the database tsk table.
What is the best choice for this kind of situation ?

Many thanks and regards,

Yves

[kev1n]

I think the Display object is the best choice.