Each Recital table can have one or more data dictionaries to provide a central repository for constraints and other metadata.
Here's how to set up field validation for a field with a small static number of acceptable values.
Using the example.dbf table from the southwind sample database, validation can be added to the title field to ensure it matches one of a list values.
altertable example addconstraint;(titlesetcheckinlist(alltrim(title),"Miss","Mr","Mrs","Ms"))
The inlist() function checks whether the specified expression exists in the comma-separated list which follows. An attempt to update title with a value not in the list will give an error: Validation on field 'TITLE' failed.
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.