I would like to determine the number of records that a query on a Tokyo Cabinet Table will return before I run the query. I am using the rufus-tokyo Ruby gem as my interface. What is the best way to do this?
Looking thorough the code on github, I think I found the answer. It would use db#query_count method which returns a record count. Here's an example of paging records using query_count:
db = Rufus::Tokyo::Table.new(@file)
begin
# Need to find the total number of records that would be returned.
# could use db#size, except that our query filters out records after today.
total_count = db.query_count { |q|
q.add_condition 'date', :numle, @today
q.order_by 'date', :strdesc
}
pager = IndexCards::Pager.new requested_page_num, total_count
# Now let's pull the slice that we want.
results = db.query { |q|
q.add_condition 'date', :numle, @today
q.order_by 'date', :strdesc
q.limit(pager.limit, pager.offset)
}
ensure
db.close
end