What's shown is not a one to one relationship, but rather a relationship between unindexed match fields. The "T" connection, when used between FileMaker tables, indicates that the field is either unindexed, unstored or global.
But I have this nagging recollection that this is not the case for External ODBC sourced tables so I suggest you check and see if the tables/relationships function correctly. It may be just how FileMaker shows the connectors for these data sources.
Hi Phil, thank you for the answer, it made us looking for some other stuff which resulted in the following:
- Changing some settings in the mysql database (like innoDB)
- (Re)made a primary key with: INT (length 11) and set to auto-increment for the id.
- 'Allow Null' for all other fields.
After this it worked :) It's a bit searching for a needle in the haystack...