Enum ForeignKeys 

#[non_exhaustive]
pub enum ForeignKeys {
    Rust,
    SQLite,
}

Which method should be used to check foreign-key constraints.

The default is ForeignKeys::SQLite, but this is likely to change to ForeignKeys::Rust.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Rust

Foreign-key constraints are checked by rust-query only.

Most foreign-key checks are done at compile time and are thus completely free. However, some runtime checks are required for deletes.

SQLite

Foreign-key constraints are checked by SQLite in addition to the checks done by rust-query.

This is useful when using rust-query with crate::TransactionWeak::rusqlite_transaction or when other software can write to the database. Both can result in “dangling” foreign keys (which point at a non-existent row) if written incorrectly. Dangling foreign keys can result in wrong results, but these dangling foreign keys can also turn into “false” foreign keys if a new record is inserted that makes the foreign key valid. This is a lot worse than a dangling foreign key, because it is generally not possible to detect.

With the ForeignKeys::SQLite option, rust-query will prevent creating such false foreign keys and panic instead. The downside is that indexes are required on all foreign keys to make the checks efficient.