Add #query_each . Fixes #18

spec/dummy_driver_spec.cr

@@ -208,6 +208,24 @@ describe DummyDriver do
       end
     end
 
+    describe "query each" do
+      it "queries" do
+        with_dummy do |db|
+          i = 0
+          db.query_each "3,4 1,2" do |rs|
+            case i
+            when 0
+              rs.read(Int64, Int64).should eq({3i64, 4i64})
+            when 1
+              rs.read(Int64, Int64).should eq({1i64, 2i64})
+            end
+            i += 1
+          end
+          i.should eq(2)
+        end
+      end
+    end
+
     it "reads multiple values" do
       with_dummy do |db|
         db.query "3,4 1,2" do |rs|

src/db/query_methods.cr

@@ -166,10 +166,8 @@ module DB
     # ```
     def query_all(query, *args, &block : ResultSet -> U) : Array(U) forall U
       ary = [] of U
-      query(query, *args) do |rs|
+      query_each(query, *args) do |rs|
-        rs.each do
+        ary.push(yield rs)
-          ary.push(yield rs)
-        end
       end
       ary
     end
@@ -198,6 +196,22 @@ module DB
       end
     end
 
+    # Executes a *query* and yields the `ResultSet` once per each row.
+    # The `ResultSet` is closed automatically.
+    #
+    # ```
+    # db.query_each "select name from contacts" do |rs|
+    #   puts rs.read(String)
+    # end
+    # ```
+    def query_each(query, *args)
+      query(query, *args) do |rs|
+        rs.each do
+          yield rs
+        end
+      end
+    end
+
     # Performs the `query` and returns an `ExecResult`
     def exec(query, *args)
       build(query).exec(*args)