| Subject | Error creating Foreign key | 
|---|---|
| Author | Mourad Hedfi | 
| Post date | 2018-05-31T06:37:19Z | 
Hello everybody,
I've an application witch update a database data.
The process to update data is :
- Delete all foreign keys
- Execute all update commands (insert, update, delete)
- Create foreign keys
The problem is that foreign key creation return an error for some FK (50 from 477).
"-607-This operation is not defined for system tables."
"Table is in use."
It's a strange error because I've only one connection to the database in the application and database is not opened in any other editor.
I've tried the following solutions : 
- In the application, before creating FK, I close the database connecion and I reopen it
- I've backuped and restored the database
but always the same error.
I'm on Firebird 1.5 on Windows.
Can anyone tell me what's wrong and how to fix this problem
​Best regards.