StatementCache

Statement cache is used to cache a single statement in order to avoid creating the AST again. Initializing the cache is done by passing the statement in the create block:

cache = StatementCache.create(Book.connection) do |params|
  Book.where(name: "my book").where("author_id > 3")
end

The cached statement is executed by using the {connection.execute}[rdoc-ref:ConnectionAdapters::DatabaseStatements#execute] method:

cache.execute([], Book, Book.connection)

The relation returned by the block is cached, and for each {execute}[rdoc-ref:ConnectionAdapters::DatabaseStatements#execute] call the cached relation gets duped. Database is queried when to_a is called on the relation.

If you want to cache the statement without the values you can use the bind method of the block parameter.

cache = StatementCache.create(Book.connection) do |params|
  Book.where(name: params.bind)
end

And pass the bind values as the first argument of execute call.

cache.execute(["my book"], Book, Book.connection)