leave a single scalar value returns DB::Any

spec/std/db/dummy_driver.cr

@@ -36,6 +36,8 @@ class DummyDriver < DB::Driver
   end
 
   class DummyResultSet < DB::ResultSet
+    @@next_column_type = String
+
     def initialize(statement, query)
       super(statement)
       @iterator = query.split.map { |r| r.split(',') }.to_a.each
@@ -70,7 +72,11 @@ class DummyDriver < DB::Driver
     end
 
     def column_type(index : Int32)
-      String
+      @@next_column_type
+    end
+
+    def self.next_column_type=(value)
+      @@next_column_type = value
     end
 
     private def read? : DB::Any?

spec/std/db/dummy_driver_spec.cr

@@ -110,32 +110,25 @@ describe DummyDriver do
       end
     end
 
-    it "should get Int32 scalars by default" do
+    it "should get Nil scalars" do
       with_dummy do |db|
-        db.scalar("1").should be_a(Int32)
-        db.scalar?("1").should be_a(Int32)
-        db.scalar?("NULL").should be_nil
-      end
-    end
-
-    it "should get String scalars" do
-      with_dummy do |db|
-        db.scalar(String, "foo").should eq("foo")
+        DummyDriver::DummyResultSet.next_column_type = Nil
+        db.scalar("NULL").should be_nil
       end
     end
 
     {% for value in [1, 1_i64, "hello", 1.5, 1.5_f32] %}
       it "numeric scalars of type of {{value.id}} should return value or nil" do
         with_dummy do |db|
-          db.scalar(typeof({{value}}), "#{{{value}}}").should eq({{value}})
-          db.scalar?(typeof({{value}}), "#{{{value}}}").should eq({{value}})
-          db.scalar?(typeof({{value}}), "NULL").should be_nil
+          DummyDriver::DummyResultSet.next_column_type = typeof({{value}})
+          db.scalar("#{{{value}}}").should eq({{value}})
         end
       end
 
       it "should set positional arguments for {{value.id}}" do
         with_dummy do |db|
-          db.scalar(typeof({{value}}), "?", {{value}}).should eq({{value}})
+          DummyDriver::DummyResultSet.next_column_type = typeof({{value}})
+          db.scalar("?", {{value}}).should eq({{value}})
         end
       end
     {% end %}
@@ -144,7 +137,8 @@ describe DummyDriver do
       with_dummy do |db|
         ary = UInt8[0x53, 0x51, 0x4C]
         slice = Slice.new(ary.to_unsafe, ary.size)
-        db.scalar(Slice(UInt8), "?", slice).to_a.should eq(ary)
+        DummyDriver::DummyResultSet.next_column_type = typeof(slice)
+        (db.scalar("?", slice) as Slice(UInt8)).to_a.should eq(ary)
       end
     end
   end

spec/std/db/statement_spec.cr

@@ -32,17 +32,7 @@ describe DB::Statement do
   it "should initialize positional params in scalar" do
     with_dummy do |db|
       stmt = db.prepare("the query")
-      stmt.scalar String, "a", 1, nil
-      stmt.params[0].should eq("a")
-      stmt.params[1].should eq(1)
-      stmt.params[2].should eq(nil)
-    end
-  end
-
-  it "should initialize positional params in scalar?" do
-    with_dummy do |db|
-      stmt = db.prepare("the query")
-      stmt.scalar? String, "a", 1, nil
+      stmt.scalar "a", 1, nil
       stmt.params[0].should eq("a")
       stmt.params[1].should eq(1)
       stmt.params[2].should eq(nil)
@@ -83,14 +73,6 @@ describe DB::Statement do
     end
   end
 
-  it "scalar should not close statement" do
-    with_dummy do |db|
-      stmt = db.prepare "3,4 1,2"
-      stmt.scalar?
-      stmt.closed?.should be_false
-    end
-  end
-
   it "exec should not close statement" do
     with_dummy do |db|
       stmt = db.prepare "3,4 1,2"

src/db/query_methods.cr

@@ -40,36 +40,12 @@ module DB
       prepare(query).exec(*args)
     end
 
-    # Performs the `query` and returns a single scalar `Int32` value
+    # Performs the `query` and returns a single scalar `DB::Any` value
+    # puts db.scalar("SELECT MAX(name)") as String # => (a String)
     def scalar(query, *args)
       prepare(query).scalar(*args)
     end
 
-    # TODO remove scalar?  make it always nillable. raise if 0-rows   raise +1-rows
-
-    # Performs the `query` and returns a single scalar value of type `t`.
-    # `t` must be any of the allowed `DB::Any` types.
-    #
-    # ```
-    # puts db.scalar(String, "SELECT MAX(name)") # => (a String)
-    # ```
-    def scalar(t, query, *args)
-      prepare(query).scalar(t, *args)
-    end
-
-    # Performs the `query` and returns a single scalar `Int32 | Nil` value
-    def scalar?(query, *args)
-      prepare(query).scalar?(*args)
-    end
-
-    # Performs the `query` and returns a single scalar value of type `t` or `Nil`.
-    # `t` must be any of the allowed `DB::Any` types.
-    #
-    # ```
-    # puts db.scalar?(String, "SELECT MAX(name)") # => (a String | Nil)
-    # ```
-    def scalar?(t, query, *args)
-      prepare(query).scalar?(t, *args)
-    end
+    # TODO add query_row
   end
 end

src/db/statement.cr

@@ -26,30 +26,27 @@ module DB
 
     # See `QueryMethods#scalar`
     def scalar(*args)
-      scalar(Int32, *args)
-    end
-
-    # See `QueryMethods#scalar`. `t` must be in DB::TYPES
-    def scalar(t, *args)
       query(*args) do |rs|
         rs.each do
-          return rs.read(t)
-        end
-      end
-
-      raise "no results"
-    end
-
-    # See `QueryMethods#scalar?`
-    def scalar?(*args)
-      scalar?(Int32, *args)
-    end
-
-    # See `QueryMethods#scalar?`. `t` must be in DB::TYPES
-    def scalar?(t, *args)
-      query(*args) do |rs|
-        rs.each do
-          return rs.read?(t)
+          # return case rs.read?(rs.column_type(0)) # :-( Some day...
+          t = rs.column_type(0)
+          if t == String
+            return rs.read?(String)
+          elsif t == Int32
+            return rs.read?(Int32)
+          elsif t == Int64
+            return rs.read?(Int64)
+          elsif t == Float32
+            return rs.read?(Float32)
+          elsif t == Float64
+            return rs.read?(Float64)
+          elsif t == Slice(UInt8)
+            return rs.read?(Slice(UInt8))
+          elsif t == Nil
+            return rs.read?(Int32)
+          else
+            raise "not implemented for #{t} type"
+          end
         end
       end