Then EF removes the Account and the related AccountEmp rows (but did not remove the Emp objects themselfs).ġ) so can i conclude that EF will implement "Set Null" as the Delete rule for a one-to-many relation. ![]() It has many templates and a well-curated workspace. It also allows integration with Microsoft Outlook. It keeps track of the workflow from the inception of the tasks to tracking and completion by producing reports. when i wrote the following:- public ActionResult Index4 Taskade provides charts and spreadsheets to report on the progress of a project. by defualt EF will do "Cascade on delete" when trying to delete a parent object that have child on a many-to-many relation. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted. When a change is made to a relationship, the related foreign-key property is set to a null value. Then EF will NOT try to remove the related Emps, instead it will only try to set the Emp.DeptID FK as null ,and since the FK is required so i got the following exception:- The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. Var dept = t.Depts.Include(w=>w.Emps).SingleOrDefault(a => a.DeptID = 1) by default EF will implement the Delete Rule as "Set Null" when trying to delete a Parent object that have child through a one-to-many relation.įor example when i wrote the following:- public ActionResult Index2() Method, and i came out with these outcomes:. Now i did some tests on how EF deals withe. Now when i map these 4 tables inside EF 6.0 i got the following three model classes:- public partial class Account Emp & Account with many-to-many (through the AccountEmp table). ![]() I have four tables inside my DB Emp,Dept,Account,AccountEmp.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |