检查提交的事务，如果返回则返回一个值

Question

我想在用户表中插入一个新用户（电子邮件地址）。如果成功（没有重复），请将新用户的基本配置插入其他表，然后将一些数据返回给客户端。如果不成功，则在C＃项目的数据集中接收相关的通知。

这里是示例代码，因此您可以轻松对其进行评论

ALTER PROCEDURE [dbo].[CreateUser] 
  @Email nvarchar(256),   
  @Password nvarchar(256)   
AS
BEGIN
  declare @UserID uniqueidentifier;
  declare @ConfigID uniqueidentifier;
  declare @TopMostNode uniqueidentifier;

  BEGIN TRANSACTION;
    select @UserID = NEWID();
    select @ConfigID = newid();

    insert into Users (UserID,Email,Password,CurrentConfig) 
      values(@UserID, @Email, @Password, @ConfigID);

    INSERT INTO Configs (ConfigID, OwnerID, DisplayName, LastPrintID)
      VALUES (@ConfigID,@UserID, 'Default Config', 1);

  COMMIT TRANSACTION 
END

Answer 1

该代码几乎完整。只需添加一个SELECT即可返回新键。如果发生错误，您将获得一个例外。 EG：

ALTER PROCEDURE [dbo].[CreateUser] 
  @Email nvarchar(256),   
  @Password nvarchar(256)   
AS
BEGIN
  declare @UserID uniqueidentifier;
  declare @ConfigID uniqueidentifier;
  declare @TopMostNode uniqueidentifier;

  BEGIN TRANSACTION;
    select @UserID = NEWID();
    select @ConfigID = newid();

    insert into Users (UserID,Email,Password,CurrentConfig) 
      values(@UserID, @Email, @Password, @ConfigID);

    INSERT INTO Configs (ConfigID, OwnerID, DisplayName, LastPrintID)
      VALUES (@ConfigID,@UserID, 'Default Config', 1);

  COMMIT TRANSACTION 
  select @UserID UserID, @ConfigID ConfigID;
END

Answer 2

这里是一种可能，它返回一个记录集，其中包含所需的数据和一个标志以指示用户是否已经存在。

alter procedure [dbo].[CreateUser]
(
  @Email nvarchar(256)  
  , @Password nvarchar(256)
)
as
begin
  declare @UserID uniqueidentifier, @ConfigID uniqueidentifier, @TopMostNode uniqueidentifier, @UserExists bit = 0;

  select @UserID = UserID, @UserExists = 1 from Users where Email = @Email;

  if @UserExists = 0 begin
    begin transaction;
      set @UserID = newid();
      set @ConfigID = newid();

      insert into Users (UserID, Email, [Password], CurrentConfig) 
        values (@UserID, @Email, @Password, @ConfigID);

      insert into Configs (ConfigID, OwnerID, DisplayName, LastPrintID)
        values (@ConfigID, @UserID, 'Default Config', 1);

    commit transaction 
  end

  -- Return whether the user already exists or not and the user id
  select @UserExists, @UserId

  return 0;
end

[将数据返回到应用程序的另一种方法是使用output参数，例如

alter procedure [dbo].[CreateUser]
(
  @Email nvarchar(256)  
  , @Password nvarchar(256)
  , @UserId uniqueidentifier out
  , @UserExists bit out
)
as
begin
  declare @ConfigID uniqueidentifier, @TopMostNode uniqueidentifier;

  set @UserExists = 0;

  select @UserID = UserID, @UserExists = 1 from Users where Email = @Email;

  if @UserExists = 0 begin
    begin transaction;
      set @UserID = newid();
      set @ConfigID = newid();

      insert into Users (UserID, Email, [Password], CurrentConfig) 
        values (@UserID, @Email, @Password, @ConfigID);

      insert into Configs (ConfigID, OwnerID, DisplayName, LastPrintID)
        values (@ConfigID, @UserID, 'Default Config', 1);

    commit transaction 
  end

  return 0;
end