I am trying to save Employee details, which has references with City. But everytime I try to save my contact, which is validated I get the exception “ADO.Net Entity Framework An entity object cannot be referenced by multiple instances of IEntityChangeTracker”
I’m using the EF to try to update an entity with ASP.NET. I’m creating an entity, setting it’s properties then passing it back to the EF on a separate layer with the ID so the change can be applied. I’m doing this because I only store the ID of the entity when it’s been bound to the UI controls.
What is the related_name argument useful for on ManyToManyField and ForeignKey fields? For example, given the following code, what is the effect of related_name='maps'?
The new version of SQLite has the ability to enforce Foreign Key constraints, but for the sake of backwards-compatibility, you have to turn it on for each database connection separately!
How can I change the display text in a <select> field while selecting a field which is a ForeignKey?