Getting Invalid column name 'EmploymentTypeEntityEmploymentTypeID in Entity framework core

Question

I am getting the below error.

Message: Microsoft.EntityFrameworkCore.DbUpdateException : An error occurred while updating the entries. See the inner exception for details. ----> System.Data.SqlClient.SqlException : Invalid column name 'EmploymentTypeEntityEmploymentTypeID'.

Its strange as its combining my Entity Class Name and the Entity Property Name.

Below is my code.

SystemTest.cs

   using (var transaction = _referenceDataDbContext.Database.BeginTransaction())
            {
                _referenceDataDbContext.EmploymentType.AddRangeAsync(

                    new EmploymentTypeEntity
                    {
                        EmploymentTypeID = 1,
                        EmploymentType = "EmploymentType",
                        CategoryTypeID = 27,

                        SiteAddress = null,
                        CreatedBy = "UnitTest",
                        CreatedOn = DateTime.Now,
                        ModifiedBy = "UnitTest",
                        ModifiedOn = DateTime.Now,
                        RowVersion = new RowVersion(1),
                        EmploymentTypeGroups = new[]
                        {
                        new EmploymentTypeGroupEntity
                        {
                            EmploymentTypeGroupID = 11, GroupName = "Child Care", IsActive = true
                        }
                        }
                    }

                    }
                );

                _referenceDataDbContext.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [ref].[EmploymentType] ON");

                _referenceDataDbContext.SaveChanges();
            }

EmploymentTypeGroup.cs

  public class EmploymentTypeGroupEntity
    {
        [Key]
        public int? EmploymentTypeGroupID { get; set; }
        public string GroupName { get; set; }
        public bool? IsActive { get; set; }
        public DateTime? CreatedOn { get; set; }
        public string CreatedBy { get; set; }
        public DateTime? ModifiedOn { get; set; }
        public string ModifiedBy { get; set; }

        [Timestamp]
        [ConcurrencyCheck]
        public byte[] RowVersion { get; set; }

    }

EmploymentType.cs

public class EmploymentTypeEntity
    {
        [Key]
        public int? EmploymentTypeID { get; set; }
        public string EmploymentType { get; set; }
        public int? CategoryTypeID { get; set; }

        public bool? SiteAddress { get; set; }
        public IEnumerable<EmploymentTypeGroupEntity> EmploymentTypeGroups { get; set; }
        public DateTime? CreatedOn { get; set; }
        public string CreatedBy { get; set; }
        public DateTime? ModifiedOn { get; set; }
        public string ModifiedBy { get; set; }

        [Timestamp]
        [ConcurrencyCheck]
        public byte[] RowVersion { get; set; }
    }

DataDbContext.cs

public class ReferenceDataDbContext : DbContext
    {
        public ReferenceDataDbContext(DbContextOptions<ReferenceDataDbContext> options)
            : base(options)
        {
        }

        public ReferenceDataDbContext()
        {

        }


        public virtual DbSet<EmploymentTypeEntity> EmploymentType { get; set; }
        public virtual DbSet<EmploymentTypeGroupEntity> EmploymentTypeGroup { get; set; }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.Entity<StateEntity>().ToTable("State", "ref");
            builder.Entity<EmploymentTypeGroupEntity>().ToTable("EmploymentTypeGroup", "ref");
            builder.Entity<EmploymentTypeEntity>().ToTable("EmploymentType","ref").HasMany(a => a.EmploymentTypeGroups);

            // Configure database attributes
        }
    }

Answer 1

You are creating a relationship between EmploymentTypeGroupEntity and EmploymentTypeEntity. But you are not telling Entity Framework what that relationship is. EF has guessed that you want a reference to EmploymentTypeEntity in your EmploymentTypeGroupEntity table and created a field for that. This clearly isn't what you want.

You need to tell EF what the relationship is. If it is a one-many relationship where one EmploymentTypeEntity can have many EmploymentTypeGroupEntity's, which appears to be the case because you have defined:

public IEnumerable<EmploymentTypeGroupEntity> EmploymentTypeGroups { get; set; }

You also need to create a foreign key in your EmploymentTypeGroupEntity class. so add to this class:

public int EmploymentTypeEntityID { get; set; }

[ForeignKey(nameof(EmploymentTypeEntityID))]
public EmploymentTypeEntity EmploymentTypeEntity  { get; set; }

In your EmploymentTypeEntity class change the collection type:

public ICollection<EmploymentTypeGroupEntity> EmploymentTypeGroups { get; set; }

Add a constructor to assign a new List<EmploymentTypeGroupEntity>() to EmploymentTypeGroups.

Change the array assignment in your tests to add to the collection and add the foreign key to the groups creation.