When you connect to an existing SQLite database from XMLSpy, or when you create a new one, foreign key constraints are enabled by default. Foreign key constraints help preserve the integrity of data in your database. For example, when foreign keys are enabled, it is not possible to delete a record from a table if it has dependencies in another table.
In certain cases, you may want to temporarily override this behavior and disable foreign keys, perhaps, in order to update or insert multiple rows of data without getting data validation errors. To explicitly disable foreign keys before connecting to the SQLite database, select the Disable Foreign Keys option available on the database connection wizard.
"Connect to SQLite" wizard page
When foreign keys are disabled, you will be able to perform operations against data that would otherwise not be possible due to validation checks. At the same time, however, there is also the risk of introducing incorrect data in the database, or creating "orphaned" rows. (An example of an "orphaned" row would be an address in the "addresses" table not linked to any person in the "person" table, because the person was deleted but its associated address was not.)