Relationships (via lookup) in Zoho Creator

Hi,

I have a question regarding Zoho Creator lookup. I'm wondering how relationships (lookups) are defined "internally" on Zoho Creator.
It seems that lookup fields accept any arbitrary data type and not keys/ID's of the referenced items.

If a field I specify as the lookup is "Name", and I point to that field in lookup, "Name" must be unique?

How does this compare to standard databases which usually use a unique ID/key to creation relationships?
Is this more comparable to say Access database?

I'm very interested in using Zoho for a large application but I need clarification on this bit before I go any further.

Thanks for any input