If a relationship in FileMaker does not work or sometimes does not work, the problem may be due to the length of the field content. The maximum length of key fields in different databases are
PostgreSQL: 8000 bytes
mySQL: 767 bytes
mariaDB: 767 bytes
Oracle: 4000 bytes
FileMaker: 100 bytes (version 21)
So if a key in FileMaker can be longer than 100 characters, the ‘solution’ would be to create several multikey fields and combine them in the relationship with the = operator.
