Cannot create more than one clustered index on table

Question

I am having the following error after typing update-database:

Cannot create more than one clustered index on table \'dbo.AppUsers\'. Drop the existing clu

Answer 1

As stated by @gorillapower in comments, this piece of code is also very important.

modelBuilder.Conventions.Add(new AttributeToColumnAnnotationConvention<TableColumnAttribute, string>( "ServiceTableColumn", (property, attributes) => attributes.Single().ColumnType.ToString()));

inside your

protected override void OnModelCreating(DbModelBuilder modelBuilder)

in the DbContext config class. Do not forget to regenerate migrations.

Answer 2

Generally, this error message is caused by not running the Mobile Apps/Mobile Services DB generator. Entity Framework does not have an annotation for creating a clustered index that is not a primary key, so the mobile server SDK manually creates the right SQL statements to set CreatedAt as a non-primary key clustered index.

To resolve this, run the database generator before migrations are applied. In the Migrations\Configuration.cs file, include the following:

public Configuration()
{
   AutomaticMigrationsEnabled = false;
   SetSqlGenerator("System.Data.SqlClient", new EntityTableSqlGenerator());
}

To learn more, see How to make data model changes to a .NET backend mobile service. The topic applies to both Mobile Services and Mobile Apps, though some namespaces are different in Mobile Apps.