Creating a UNIQUE Filtered Index for NULL values on Entity Framework

问题

I'm trying to create a table that has a UNIQUE Filtered Index for NULL values (eg. Allow Null values to be duplicates) using Entity Framework.

I am using Fluent API and have this entity property:

modelBuilder.Entity<Client>().Property(c => c.Barcode)
            .HasMaxLength(20)
            .IsRequired()
            .HasColumnAnnotation(
                IndexAnnotation.AnnotationName,
                new IndexAnnotation(new IndexAttribute("IX_ClientBarcode") { IsUnique = true }));

I found that SQL Server 2008 allows this for unique columns with filtered nulls:

CREATE UNIQUE INDEX indexName ON tableName(columns) INCLUDE includeColumns WHERE columnName IS NOT NULL

Would this even be posible? Since I am using LocalDB.

回答1:

I don't think this is possible at the moment:

http://gavindraper.com/2014/06/26/entity-framework-fluent-api-and-indexing/

I am going to use an IDatabaseInitializer to add the indexes following database creation using dbContext.Database.ExecuteSqlCommand(). Hopefully support will come in a future release.

来源：https://stackoverflow.com/questions/27555538/creating-a-unique-filtered-index-for-null-values-on-entity-framework