Update to EF 9.0 and use Vector Search capability

[abbottdev]

Thanks for stopping by to let us know something could be better!

Is your feature request related to a problem? Please describe.
Cloud Spanner has introduced Vector Search capabilities; which EF 9.0 now has native support for with the IsVector extension methods.

See: https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-9.0/whatsnew#vector-similarity-search-preview

Describe the solution you'd like
Be able to define a column as a Vector type using EF and the DDL created for Cloud Spanner marks up the ARRAY type as a Vector index.

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Blog>()
            .Property(b => b.Embeddings)
            .IsVector(DistanceFunction.Cosine, dimensions: 1536);
    }

When using the Where predicate, if the operator is a Vector Search, the translated SQL statements generated are vector searches:

var blogs = await context.Blogs
    .OrderBy(s => EF.Functions.VectorDistance(s.Vector, vector))
    .Take(5)
    .ToListAsync();