Editor with a database schema which is not public and which has a specific name

Hello everybody.
I use editor with Join tables - one-to-many join and a database in a specific schema. I can't manage to find the syntax for the Mjoin in the php file.
I try with 'as' syntax, with ->name but the problem is with the link table in '->link'.
In sql command you must specfy the schema for example 'schema.table' or 'schema.table.column'.
Can you help me to write the php file please?
Thanks for your help.
Lionel