||Ten MySQL Best Practices|
|Subject:||About pointers to files (item 4)|
It should be noted that storing files outside the database and storing only pointers to files inside the database shoulb be done with care.
The filesystem on which the files are to be stored should be secured appropriately.
Also, the benefit of referential integrity is lost, and should be re-implemented in the business layer. Only if it is not essential that pointers to files point to actual data, using such pointers is trivial.
Therefore, I think it should be well considered whether to use file pointers or blobs when designing a database.