Хранимая процедура upDBTreeRemoveNode

   Процедура исключает узел из дерева без его удаления из базы.

CREATE PROCEDURE [upDBTreeRemoveNode]
   @idDBTree INT,
   @idNode INT
AS
    DECLARE @Error INT
    SET @Error=0

    IF NOT Exists(SELECT *  FROM DBTree  WHERE idDBTree=@idDBTree AND idNode=@idNode) BEGIN 
         RAISERROR ('Нет такого узла',16,1)
         RETURN 1
    END
    IF @@ERROR<>0 SET @Error=@@ERROR
    DECLARE @idPrior int,@idNext int, @idParent int,@idFirstChild int
    SELECT @idPrior=idPrior, @idNext=idNext,@idParent=idParent,@idFirstChild=idFirstChild FROM DBTree WHERE idDBTree=@idDBTree AND idNode=@idNode
    IF @@ERROR<>0 SET @Error=@@ERROR
    BEGIN TRAN
    IF @idPrior IS NULL AND @idNext IS NULL AND @idParent IS NOT NULL 
      BEGIN
           UPDATE DBTree SET idFirstChild=NULL WHERE idDBTree=@idDBTree AND idNode=@idParent 
           IF @@ERROR<>0 SET @Error=@@ERROR
      END
    ELSE IF @idPrior IS NULL AND @idNext IS NOT NULL 
      BEGIN 
           UPDATE DBTree SET idFirstChild=@idNext WHERE idDBTree=@idDBTree AND idNode=@idParent 
           IF @@ERROR<>0 SET @Error=@@ERROR
           UPDATE DBTree SET idPrior=NULL WHERE idDBTree=@idDBTree AND idNode=@idNext
           IF @@ERROR<>0 SET @Error=@@ERROR
      END 
    ELSE IF @idPrior IS NOT NULL AND @idNext IS NULL 
      BEGIN
           UPDATE DBTree SET idNext=NULL WHERE idDBTree=@idDBTree AND idNode=@idPrior
           IF @@ERROR<>0 SET @Error=@@ERROR
      END
    ELSE IF @idPrior IS NOT NULL AND @idNext IS NOT NULL
      BEGIN 
           UPDATE DBTree SET idNext=@idNext WHERE idDBTree=@idDBTree AND idNode=@idPrior 
           IF @@ERROR<>0 SET @Error=@@ERROR
           UPDATE DBTree SET idPrior=@idPrior WHERE idDBTree=@idDBTree AND idNode=@idNext
           IF @@ERROR<>0 SET @Error=@@ERROR
      END 
    IF @Error=0 
          COMMIT TRAN
    ELSE BEGIN
           ROLLBACK TRAN
           RETURN 1 
    END