SaveChanges Transaction

Entity Framework Core (EF Core) does wrap the SaveChanges method in a transaction by default. When you call SaveChanges to persist changes to the database, EF Core ensures that all the changes are committed as a single transaction. This means that if any part of the operation fails (e.g., due to a validation error or a database constraint violation), none of the changes will be applied to the database.

Here's how it works:

1. You make changes to your entity objects within a DbContext.
2. When you call SaveChanges, EF Core starts a database transaction.
3. EF Core applies all the changes to the database within this transaction.
4. If all changes are successfully applied, the transaction is committed, making the changes permanent.
5. If any part of the operation fails (e.g., an exception is thrown), the transaction is rolled back, and no changes are applied to the database.

This behavior ensures that your data remains in a consistent state, and either all changes are applied or none are. If you need more control over transactions, such as specifying isolation levels or manually managing transactions, EF Core provides options for doing so. You can use methods like BeginTransaction, Commit, and Rollback on the DbContext's Database property to work with transactions explicitly.