How can I use the Entity Framework 4.1 "code only" fluent API to map a char property?

char ef4-code-only entity-framework fluent-interface

Question

I have an object that has a char property:

public class Product
{
    public char Code
    {
        get;
        set;
    }
}

Entity Framework doesn't seem to be able to map chars (this field is missing from the database when I create the database schema from my model objects). Is there anyway I can map the char (e.g. to a string) using the fluent API? I don't want to change the model objects as they are part of a legacy shared library.

1
46
7/20/2011 10:55:09 AM

Accepted Answer

Char is not valid primitive type for entity framework = entity framework doesn't map it. If you check CSDL reference you will see list of valid types (char is not among them).

Database char(1) is translated as string (SQL to CSDL translation). Char is described as non-unicode string with fixed length 1.

The only ugly option is second mapped property using string and your char non-mapped property will just use string[0] from that property. That is just another example how some simple type mapping or converters are damn missing in EF.

73
5/23/2017 12:17:55 PM

Popular Answer

In Fluent API you can specify the database column data type using the HasColumnType method like this:

modelBuilder.Entity<Product>()   
.Property(p => p.Code)   
.HasColumnType("char");

According to Andre Artus' answer here, HasColumnType is available in EF4.1.

For those using Data Annotations, the ColumnAttribute can accomplish the same thing.

[Column(TypeName="char")]
public string Code { get; set; }


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