Field Validation in the same table (entity)

[hamilton]

Hello guys,
I need to validate a field as follows: I need to validate if a given field (or more) is already registered in the same table (entity). If it is already registered do not let save and show error message.
How I do it?

[telecastg]

Try using dynamic logic as follows:

Administration > Entity Manager > {your entity name} > Fields > {your field name}

In the field editing window go to the Dynamic Logic panel (bottom) and click "Edit" in the " Conditions making field read-only" line and enter {your field name} Is Not Empty.

The above will turn your field read-only if it has a value already.