順序發票號碼SQL服務器

Question

我有一張發票表，其中有InvoiceID（int identity）主鍵。以及一個整數列的InvoiceNumber。我有另一張表格用於生成名爲Invoice_Numbers的發票號碼（請參見下文）。爲了確保發票號碼是唯一的，並防止我實施了下面的代碼。有人可以檢查這些代碼並評論其可靠性嗎？在多用戶環境中運行SQL 2008。

在插入發票期間，當用戶撥打主機時，用戶獲得相同發票號碼的機會是多少？

 
IF EXISTS 
    (SELECT * 
    FROM sys.objects 
    WHERE object_id = OBJECT_ID(N'[Imports].[Invoices_Numbers]') 
      AND type IN (N'U')) 
    DROP TABLE [Imports].[Invoices_Numbers]
 

GO
 

CREATE TABLE [Imports].[Invoices_Numbers] 
    (
    [InvoiceNumber] [INT] IDENTITY(1, 1) NOT NULL 
    ,[Deleted]  [BIT] NOT NULL 
    ,[Used]   [BIT] NOT NULL, 
    CONSTRAINT [PK_Invoices_Numbers] PRIMARY KEY CLUSTERED ([InvoiceNumber] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) 
ON [PRIMARY]
 

GO
 

ALTER PROCEDURE [Imports].[Get_Invoice_Number] 
(
    @InvoiceNumber INT OUTPUT 
) 
AS 
    BEGIN 
     DECLARE @NewNumber INT 
     DECLARE @MinNumber INT
 

BEGIN TRAN 

    SELECT @MinNumber = MIN(InvoiceNumber) 
    FROM Imports.Invoices_Numbers 

    IF @MinNumber > 1 
    BEGIN 
     SET IDENTITY_INSERT Imports.Invoices_Numbers ON; 

     INSERT Imports.Invoices_Numbers 
     (
      Invoicenumber 
      ,Deleted 
      ,Used 
     ) 
     VALUES 
     (
      1 
      ,0 
      ,1 
     ) 
     SET IDENTITY_INSERT Imports.Invoices_Numbers OFF; 
     SET @NewNumber=1 
    END 
    ELSE 
    BEGIN 
     WITH Gaps 
      AS (SELECT TOP 1 a.InvoiceNumber + 1 AS GapValue 
       FROM Imports.Invoices_Numbers a 
       WHERE NOT EXISTS 
          (SELECT * 
          FROM Imports.Invoices_Numbers b 
          WHERE b.InvoiceNumber = a.InvoiceNumber + 1) 
         AND a.InvoiceNumber < 
          (SELECT MAX(InvoiceNumber) 
          FROM Imports.Invoices_Numbers)) 
     SELECT @NewNumber = GapValue 
     FROM Gaps 

     IF @NewNumber IS NULL 
      BEGIN 
       SELECT TOP 1 @NewNumber = InvoiceNumber 
       FROM Imports.Invoices_Numbers 
       WHERE Used = 0 
        AND Deleted = 0 
       ORDER BY InvoiceNumber 

       IF @NewNumber IS NULL 
       BEGIN 
        INSERT Imports.Invoices_Numbers 
        (
         Deleted 
         ,Used 
        ) 
        VALUES 
        (
         0 
         ,1 
        ) 
        SELECT @NewNumber = SCOPE_IDENTITY() 
       END 
       ELSE 
       BEGIN 
        UPDATE Imports.Invoices_Numbers 
        SET Used = 1 
        WHERE InvoiceNumber = @NewNumber 
       END 
      END 
     ELSE 
      BEGIN 
       SET IDENTITY_INSERT Imports.Invoices_Numbers ON; 

       INSERT Imports.Invoices_Numbers 
       (
       Invoicenumber 
       ,Deleted 
       ,Used 
      ) 
       VALUES 
       (
       @NewNumber 
       ,0 
       ,1 
      ) 
       SET IDENTITY_INSERT Imports.Invoices_Numbers OFF; 
      END 
    END 

    SELECT @InvoiceNumber = @NewNumber 

    COMMIT TRAN 

END

Answer 1

您的解決方案看起來有點複雜。除了數據導入任務外，我不會推薦使用set identity_insert。

爲了保證唯一性，我想先添加一個唯一約束：

alter table Invoices add constraint UX_Invoices_InvoiceNr unique 

那麼你可以使用一個SQL語句，這樣插入發票：

while 1=1 
    begin   
    declare @new_nr int 
    select @new_nr = max(InvoiceNr) + 1 
    from dbo.Invoices 

    if @new_nr is null 
     set @new_nr = 1 

    insert dbo.Invoices 
      (InvoiceNr, ...) 
    values (@new_nr, ...) 

    if @@rowcount = 1 
     break 
    end