So there are several similar questions on here to this, but I'm still having issues determing what exactly I'm missing in my simplified scenario.
Let's say I have the following tables, cleverly named after myself:
'JohnsParentTable' (Id, Description)
'JohnsChildTable' (Id, JohnsParentTableId, Description)
With the resulting classes looking like so
public class JohnsParentTable
{
public int Id { get; set; }
public string Description { get; set; }
public virtual ICollection<JohnsChildTable> JohnsChildTable { get; set; }
public JohnsParentTable()
{
JohnsChildTable = new List<JohnsChildTable>();
}
}
internal class JohnsParentTableConfiguration : EntityTypeConfiguration<JohnsParentTable>
{
public JohnsParentTableConfiguration()
{
ToTable("dbo.JohnsParentTable");
HasKey(x => x.Id);
Property(x => x.Id).HasColumnName("Id").IsRequired().HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
Property(x => x.Description).HasColumnName("Description").IsRequired().HasMaxLength(50);
}
}
public class JohnsChildTable
{
public int Id { get; set; }
public string Description { get; set; }
public int JohnsParentTableId { get; set; }
public JohnsParentTable JohnsParentTable { get; set; }
}
internal class JohnsChildTableConfiguration : EntityTypeConfiguration<JohnsChildTable>
{
public JohnsChildTableConfiguration()
{
ToTable("dbo.JohnsChildTable");
HasKey(x => x.Id);
Property(x => x.Id).HasColumnName("Id").IsRequired().HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
Property(x => x.Description).HasColumnName("Description").IsRequired().HasMaxLength(50);
HasRequired(a => a.JohnsParentTable).WithMany(c => c.JohnsChildTable).HasForeignKey(a => a.JohnsParentTableId);
}
}
In the database I have a row in the parent table with an Id of 1 along with two rows in the child table tied to this parent. If I do this:
var parent = db.JohnsParentTable.FirstOrDefault(a => a.Id == 1)
The object is correctly populated. However, if I try to delete this row:
var parent = new Data.Models.JohnsParentTable() { Id = 1 };
db.JohnsParentTable.Attach(parent);
db.JohnsParentTable.Remove(parent);
db.SaveChanges();
Entity framework tries to execute the following:
DELETE [dbo].[JohnsParentTable]
WHERE ([Id] = @0)
-- @0: '1' (Type = Int32)
-- Executing at 1/23/2014 10:34:01 AM -06:00
-- Failed in 103 ms with error: The DELETE statement conflicted with the REFERENCE constraint "FK_JohnsChildTable_JohnsParentTable". The conflict occurred in database "mydatabase", table "dbo.JohnsChildTable", column 'JohnsParentTableId'.
The statement has been terminated.
My question then is what exactly am I missing to ensure Entity Framework knows that it must delete the 'JohnsChildTable' rows before deleting the parent?
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…