To find the specific error run this:
SHOW ENGINE INNODB STATUS;
And look in the LATEST FOREIGN KEY ERROR
section.
The data type for the child column must match the parent column exactly. For example, since medicalhistory.MedicalHistoryID
is an INT
, Patient.MedicalHistory
also needs to be an INT
, not a SMALLINT
.
Also, you should run the query set foreign_key_checks=0
before running the DDL so you can create the tables in an arbitrary order rather than needing to create all parent tables before the relevant child tables.