class Card::Query::AbstractQuery

superclass for CardQuery, ReferenceQuery, ActQuery, and ActionQuery

Each of the Query classes handle interpretation of hash “statements” into a number of objects known to the SqlStatement class, including @conditions, @joins, @comment, and the catch-all @mods

Sql queries involving multiple tables are made possible by the query hierarchy as tracked by subqueries (children) and superqueries (parents). For example, if one card links to another, then this can be represented as a CardQuery with a ReferenceQuery child that in turn has another CardQuery as its child.

See AbstractQuery::Tie for more on how tables can be connected.