使用用户定义的表类型 sql server 插入时检查记录是否存在

Question

我正在尝试在 sql server 中批量插入记录。我正在使用用户定义的表类型来传递来自我的 .net 应用程序的记录集合。请看下面的插入查询。

INSERT INTO MachineItems([Name],[Price],[Quantity],[ItemGroupID],[SubGroup] ,[IsDefault],
    [IsRemovable],[MachineTypeID],[ItemType],[CreatedBy],[CreatedOn] )

    SELECT mi.Name
    ,mi.Price
    ,mi.Quantity
    ,(SELECT ID from ItemGroups WHERE NAME=mi.ItemGroup) as ID
    ,mi.SubGroup,
    CASE 
      WHEN mi.IsDefault ='Yes' THEN 1 
      WHEN mi.IsDefault ='No' THEN 0 
      WHEN mi.IsDefault IS NULL THEN 0
     END ,
     CASE 
      WHEN mi.IsRemovable ='Yes' THEN 1 
      WHEN mi.IsRemovable ='No' THEN 0 
     END ,
    (SELECT ID from MachineTypes WHERE Name=mi.MachineType),
    (SELECT ID from MachineItemTypes WHERE Name=mi.ItemType),
    mi.CreatedBy 
    ,mi.CreatedOn       
    FROM @MachineItems mi

我要做的是在插入记录之前进行检查，表中是否已经存在具有 [MachineTypeID] 和 [Name] 的记录。如果不存在则插入 Eles 更新记录。

如何使用用户定义的表类型来做到这一点？

Answer 1

1. 您应该使用MERGE 命令而不是直接插入。您想要做的并不是真正特定于用户定义的表类型。

2. 如果您加入 3 个子表而不是为每行执行的列创建子查询，那会更好/更有效。

例子：

MERGE MachineItems AS Target
USING (SELECT mi.Name,
              mi.Price,
              mi.Quantity,
              ig.ID, -- ItemGroupID
              mi.SubGroup,
              CASE 
                 WHEN mi.IsDefault ='Yes' THEN 1 
                 WHEN mi.IsDefault ='No' THEN 0 
                 WHEN mi.IsDefault IS NULL THEN 0
              END, -- IsDefault
              CASE 
                 WHEN mi.IsRemovable ='Yes' THEN 1 
                 WHEN mi.IsRemovable ='No' THEN 0 
              END, -- IsRemovable
              mt.ID, -- MachineTypeID
              mit.ID, -- ItemType
              mi.CreatedBy,
              mi.CreatedOn
       FROM   @MachineItems mi
       INNER JOIN ItemGroups ig
               ON ig.[Name] = mi.ItemGroup
       INNER JOIN MachineTypes mt
               ON mt.[Name] = mi.MachineType
       INNER JOIN MachineItemTypes mit
               ON mit.[Name] = mi.ItemType) AS Source (
                   [Name],[Price],[Quantity],[ItemGroupID],[SubGroup],[IsDefault],
                   [IsRemovable],[MachineTypeID],[ItemType],[CreatedBy],[CreatedOn])
ON (
         Target.[MachineTypeID] = Source.[MachineTypeID]
    AND  Target.[Name] = Source.[Name]
    )
WHEN MATCHED THEN 
     UPDATE SET Price = Source.Price,
                Quantity = Source.Quantity,
                ItemGroupID = Source.ItemGroupID,
                SubGroup = Source.SubGroup,
                IsDefault = Source.IsDefault,
                IsRemovable = Source.IsRemovable,
                MachineTypeID = Source.MachineTypeID,
                ItemType = Source.ItemType,
                CreatedBy = Source.CreatedBy,
                CreatedOn = Source.CreatedOn
WHEN NOT MATCHED BY TARGET THEN
     INSERT ([Name],[Price],[Quantity],[ItemGroupID],[SubGroup] ,[IsDefault],
             [IsRemovable],[MachineTypeID],[ItemType],[CreatedBy],[CreatedOn])
     VALUES (Source.[Name], Source.[Price], Source.[Quantity], Source.[ItemGroupID],
             Source.[SubGroup], Source.[IsDefault], Source.[IsRemovable],
             Source.[MachineTypeID], Source.[ItemType], Source.[CreatedBy],
             Source.[CreatedOn]);

Answer 2

您可以在此处使用Merge

使用Merge

1. 如果不存在，您可以插入
2. 如果已经存在，您可以删除
3. 如果已经存在，您可以更新

---

MERGE MachineItems
USING @MachineItems ON MachineItems.id = @MachineItems.id
and MachineItems.Name=@MachineItems.Name
WHEN NOT MATCHED THEN
INSERT INTO MachineItems([Name],[Price],[Quantity],[ItemGroupID],[SubGroup]         
,[IsDefault],
[IsRemovable],[MachineTypeID],[ItemType],[CreatedBy],[CreatedOn] )

    SELECT mi.Name
    ,mi.Price
    ,mi.Quantity
    ,(SELECT ID from ItemGroups WHERE NAME=mi.ItemGroup) as ID
    ,mi.SubGroup,
    CASE 
      WHEN mi.IsDefault ='Yes' THEN 1 
      WHEN mi.IsDefault ='No' THEN 0 
      WHEN mi.IsDefault IS NULL THEN 0
     END ,
     CASE 
      WHEN mi.IsRemovable ='Yes' THEN 1 
      WHEN mi.IsRemovable ='No' THEN 0 
     END ,
    (SELECT ID from MachineTypes WHERE Name=mi.MachineType),
    (SELECT ID from MachineItemTypes WHERE Name=mi.ItemType),
    mi.CreatedBy 
    ,mi.CreatedOn       
    FROM @MachineItems mi