Entity Framework The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

Question

On updating database in Entity Framework , Code first Migration, I am getting this error:

The ALTER TABLE statement conflicted with the FOREIGN KEY constr

Answer 1

this problem appear because your table is not empty. so you shoud add the new field without attaching it like foreign key. public int? MedicalGroupId { get; set; }.And execute update-database command in package manage console. Then fill the field in this table(client) with the right data (value exists in MedicalGroupsId). Insert the line to create the foreign key

[ForeignKey("MedicalGroupId")]
public virtual MedicalGroups MedicalGroup { get { return _MedicalGroup; } set { _MedicalGroup = value; } }

in the end execute the update-database command. It will be ok.