How to handle varchar columns with Entity Framework?

Question

I have a table with a `varchar` column and I am using Entity Framework to use this column in the `WHERE` clause. Entity Framework generates the query with `N''` hence the index on the column cannot be used. Is there a way to force Entity Framework to generate `varchar` query instead of `nvarchar` one?

Accepted Answer

It actually depends on how you built your EF model, if you're using its Designer you can specify the required data type for each column (in your case simply set `varchar` and you're done).

If you're using a code-first approach you have to decorate the property that represents that column with the proper attribute (`string` objects in .NET are always Unicode so it'll map `nvarchar` by default), just do this (with data annotations, if you're using `StringAttribute` then se its `IsUnicode` property to `false`):

```
[Column(TypeName = "varchar")]
public string YourColumnName
{
    get;
    set;
}
```

How to handle varchar columns with Entity Framework?

Solution

Problem