What is a FMP12 file? An FMP12 file is a database file created with FileMaker Pro 12 database development program. It contains the overall database structure (also known as database schema) along with the data inside it. The structure of an FMP12 file is based on tables where each table consists of a number of database fields having different data types. Some data types that are supported by FMP12 file format include text, custom forms, reports, datetime, blobs, and other database objects.