Closed:databases in ncbi

Question

[guardsquirrel]

Hi, I was wondering what the difference was between the ncbi nucleotide nt/nr database was to the refseq genome database and the refseq representative genome database?

When I search for alignments to my assembly in these databases, I get a very low query cover using the latter two databases, and very good query cover using nt/Nr... Is this just because it's a bigger database? Could there be anything wrong with my assembly?

Thank you