Can you describe what you want to do in more detail? Change a value in what (Field, variable, same table, different table...)? and for what purpose?
I have 2 databases with each a field with different items. If I select item A in database 1 then should automatically appaer item B in database 2.
Please describe real life situation using real table names. Only by knowing the context and purpose we can visualize your situation. :^)
What are the table names? How are the two tables related? If not related, why not? If the two tables are properly related, you have three options: 1) use a Lookup, 2) use Auto-Enter calculation or 3) simply place the related field directly on your layout.
A Simple format you can use to describe your relationships is like this:
Table1Name----<Table2Name (---< means 1 to many)
Table1name::KeyfieldName = table2Name::KeyFieldname
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