使用Entity Framework插入时有条件地设置Identity字段

Question

I'm using the Firebird ADO.NET provider with Entity Framework, but this question would also apply to other providers.

I have an field on my model as follows

    [Column("JOBNO"), DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int JobNo { get; set; }

In the database I have an 'on insert' trigger which updates the JOBNO field using a generator if JOBNO is set to NULL

By setting the DatabaseGenerated attribute to DatabaseGeneratedOption.Identity on my model's field, entity framework correctly pulls the JOBNO from the database on insert.

However sometimes I want to manually specify the JOBNO column when inserting, but EF doesn't understand and just uses the generated value.

Is there a way to allow this conditional setting of a DataBaseGenerated field?

Answer 1

I'm afraid there is no way to do a conditional setting for a DataBaseGenerated field !

1st option: Is to have the behavior of the insert trigger transfered to your application (instead of the database), this way you will always generate the id from the application.

2nd option: Is NOT TO specify the Identity and leave as NULLABLE on the database.This way you will allow EF to receive the data and when it does not receive you get the value from the trigger. (But please make sure to alter the trigger so it just create a new id when it was not provided!)