Move from the hand.

Shogi.Database/Session/Tables/Move.sql

@@ -4,12 +4,19 @@
 	[SessionId]			BIGINT NOT NULL,
 	[To]				VARCHAR(2) NOT NULL,
 	[From]				VARCHAR(2) NULL,
-	[IsPromotion]		BIT NULL,
-	[PieceIdFromHand]	INT NULL
+	[PieceIdFromHand]	INT NULL,
+	[IsPromotion]		BIT DEFAULT 0
 
 	CONSTRAINT [Cannot end where you start]
 		CHECK ([From] <> [To]),
 
+	CONSTRAINT [Move cannot start from two places]
+		CHECK (
+			( [From] IS NOT NULL AND [PieceIdFromHand] IS NULL )
+			OR
+			( [From] IS NULL AND [PieceIdFromhand] IS NOT NULL )
+		),
+
 	CONSTRAINT FK_Move_Session FOREIGN KEY (SessionId) REFERENCES [session].[Session] (Id)
 		ON DELETE CASCADE
 		ON UPDATE CASCADE,