c# EntityFramework CodeFirst migration creates a new column for existing one

Question

in my Database models i added a second Column to a table which already had one link to the same table before. My Model before my changes looks as followed:

[Table("RepairProcesses", Schema = "Data")]    
public class RepairProcess : DatabaseBase
{
    [DataMember]
    [Column("SerialNumberID")]
    public Guid SerialNumberID { get; set; }

    [ForeignKey("SerialNumberID")]
    public virtual SerialNumber SerialNumber { get; set; }
}

Now i added the second Link to the Table and the Model now looks as followed:

[Table("RepairProcesses", Schema = "Data")]    
public class RepairProcess : DatabaseBase
{
    [DataMember]
    [Column("SerialNumberID")]
    public Guid SerialNumberID { get; set; }

    [DataMember]
    [Column("ReplacementSerialNumberID")]
    public Guid? ReplacementSerialNumberID { get; set; }

    [ForeignKey("SerialNumberID")]
    public virtual SerialNumber SerialNumber { get; set; }

    [ForeignKey("ReplacementSerialNumberID")]
    public virtual SerialNumber ReplacementSerialNumber { get; set; }
}

When i now try to create the migrationscript the EntityFramework deletes the foreingn keys and creates a new column with the name SerialNumber_ID.

    public override void Up()
    {
        DropForeignKey("Data.RepairProcesses", "SerialNumberID", "Data.SerialNumbers");
        AddColumn("Data.RepairProcesses", "SerialNumber_ID", c => c.Guid());
        AddColumn("Data.RepairProcesses", "ReplacementSerialNumberID", c => c.Guid());
        CreateIndex("Data.RepairProcesses", "SerialNumber_ID");
        CreateIndex("Data.RepairProcesses", "ReplacementSerialNumberID");
        AddForeignKey("Data.RepairProcesses", "ReplacementSerialNumberID", "Data.SerialNumbers", "ID");
        AddForeignKey("Data.RepairProcesses", "SerialNumber_ID", "Data.SerialNumbers", "ID");
    }

    public override void Down()
    {
        DropForeignKey("Data.RepairProcesses", "SerialNumber_ID", "Data.SerialNumbers");
        DropForeignKey("Data.RepairProcesses", "ReplacementSerialNumberID", "Data.SerialNumbers");
        DropIndex("Data.RepairProcesses", new[] { "ReplacementSerialNumberID" });
        DropIndex("Data.RepairProcesses", new[] { "SerialNumber_ID" });
        DropColumn("Data.RepairProcesses", "ReplacementSerialNumberID");
        DropColumn("Data.RepairProcesses", "SerialNumber_ID");
        AddForeignKey("Data.RepairProcesses", "SerialNumberID", "Data.SerialNumbers", "ID");
    }

The problem is that this is a productive database and when the EF creates a new Field for the SerialNumber i lost the links to the correct field.

When i only delete the lines in the Up/Down Script which creates the new column i ran into problems because the EF Expects a Column named SerialNumber_ID.

Thanks for your help, Michael

Slava Utesinov · Accepted Answer · 2017-04-06 07:14:17Z

1

Try to change SerialNumber class this way:

public class SerialNumber 
{
    //other stuff....

    [InverseProperty("SerialNumber")]
    public virtual ICollection<RepairProcess> SerialNumbers {get;set;}

    [InverseProperty("ReplacementSerialNumber")]
    public virtual ICollection<RepairProcess> ReplacementSerialNumbers {get;set;}
}

answered Apr 6, 2017 at 7:14

Slava Utesinov

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