问题
I have a Django web-server configured to use SQLite.
In a many-to-many relationship (with extra fields), Django forces me to use the relationship model to establish a relationship between two objects. But I'm able to create a relationship between objects, that don't yet exist in the related tables.
For e.g:
I have table1 and table2 which are related via table12.
In table1, there is just one object called A.
In table2, there is just one object called X.
I can create a record in table12 that depict a relationship between A & Y; even though Y doesn't exist in table2.
My relationship model has marked the foreign keys appropriately.
回答1:
SQLite does not enforce foreign key constraints by default (mostly to be backward compatible).
To enable it, you have to execute
PRAGMA foreign_keys = 1
after you connected to the database.
See the manual about PRAGMA foreign_keys for more details.
来源：https://stackoverflow.com/questions/17213454/does-sqlite-support-referential-integrity