sql - 顺序发票编号 SQL 服务器

Question

我有一个具有 InvoiceID (int identity) 主键的发票表。和一列 InvoiceNumber，它是一个整数。我有另一个表用于生成名为 Invoice_Numbers 的发票编号（见下文）。为了确保发票号码是唯一的并防止出现空白，我实施了以下代码。有人可以查看此代码并评论其可靠性。在多用户环境中运行 SQL 2008。

用户在插入发票时致电然后进行采购时获得相同发票编号的机会有多大？

 
如果存在
   （选择 *
    FROM 系统对象
    WHERE object_id = OBJECT_ID(N'[Imports].[Invoices_Numbers]')
           并输入（N'U'））
  DROP TABLE [Imports].[Invoices_Numbers]


去

CREATE TABLE [进口].[Invoices_Numbers]
  (
     [InvoiceNumber] [INT] IDENTITY(1, 1) 非空
     ,[已删除] [BIT] 非空
     ,[已使用] [BIT] 不为空，
     约束 [PK_Invoices_Numbers] 主键集群（[InvoiceNumber] ASC）与（PAD_INDEX = OFF，STATISTICS_NORECOMPUTE = OFF，IGNORE_DUP_KEY = OFF，ALLOW_ROW_LOCKS = ON，ALLOW_PAGE_LOCKS = ON）ON [PRIMARY]
  )
开 [主要]

去

ALTER PROCEDURE [进口].[Get_Invoice_Number]
(
  @InvoiceNumber INT 输出
)
作为
  开始
      声明 @NewNumber INT
      声明 @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

结尾

Answer 1

您的解决方案看起来有点复杂。set identity_insert除了数据导入任务之外，我不建议使用它。

为了确保唯一性，我首先添加一个唯一约束：

alter table Invoices add constraint UX_Invoices_InvoiceNr unique

然后您可以使用这样的 SQL 语句插入发票：

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