To display the name of a department instead of the departmentId, create an LOV on the departmentId attribute in the view object that the ADF table is based on, pointing to the department view object.
To update your existing read-only table, remove the departmentId attribute from the JSF, and re-add it. Make sure that the new attribute is an "ADF select one choice." After the column has been added, select the select one choice drop down, and change the read-only attribute to true.
<af:selectOneChoice value="#{row.bindings.DepartmentId.inputValue}"
label="#{row.bindings.DepartmentId.label}"
required="#{bindings.Employees_VO1.hints.DepartmentId.mandatory}"
shortDesc="#{bindings.Employees_VO1.hints.DepartmentId.tooltip}"
id="soc1" readOnly="true">
If you run this page now, it should display the name of the department, instead of the id, while still being read-only.
How to show departmentName instead of departmentId using an LOV - ADF