合并两个父>子表集合

Question

我需要获取两个父>子表集合中的数据/合并到第三个父>子表中。

的表是这样的：

在三套表的唯一区别是，表C具有TableType列，以帮助辨别TableA的记录和表B记录之间的差。

我的第一个想法是使用游标。这里的代码来创建表结构，插入一些记录，然后将数据合并在一起。它工作得很好，SOOOOO ....

--Create the tables 

CREATE TABLE TableA 
(
    ID int not null identity primary key, 
    Name VARCHAR(30) 
); 

CREATE TABLE TableAChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_A FOREIGN KEY (Parent) REFERENCES TableA(ID) 
); 

CREATE TABLE TableB 
(
    ID int not null identity primary key, 
    Name VARCHAR(30) 
); 

CREATE TABLE TableBChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_B FOREIGN KEY (Parent) REFERENCES TableB(ID) 
); 

CREATE TABLE TableC 
(
    ID int not null identity primary key, 
    TableType VARCHAR(1), 
    Name VARCHAR(30) 
); 

CREATE TABLE TableCChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_C FOREIGN KEY (Parent) REFERENCES TableC(ID) 
); 

-- Insert some test records.. 

INSERT INTO TableA (Name) Values ('A1') 
INSERT INTO TableAChild (Name, Parent) VALUES ('A1Child', SCOPE_IDENTITY()) 
INSERT INTO TableB (Name) Values ('B1') 
INSERT INTO TableBChild (Name, Parent) VALUES ('B1Child', SCOPE_IDENTITY()) 

-- Needed throughout.. 
DECLARE @ID INT 

-- Merge TableA and TableAChild into TableC and TableCChild 
DECLARE TableACursor CURSOR 
    -- Get the primary key from TableA 
    FOR SELECT ID FROM TableA 
OPEN TableACursor 
    FETCH NEXT FROM TableACursor INTO @ID 

    WHILE @@FETCH_STATUS = 0 
    BEGIN 
     -- INSERT INTO SELECT the parent record into TableC, being sure to specify a TableType 
     INSERT INTO TableC (Name, TableType) SELECT Name, 'A' FROM TableA WHERE ID = @ID 

     -- INSERT INTO SELECT the child record into TableCChild using the parent ID of the last row inserted (SCOPE_IDENTITY()) 
     -- and the current record from the cursor (@ID). 
     INSERT INTO TableCChild(Name, Parent) SELECT Name, SCOPE_IDENTITY() FROM TableAChild WHERE Parent = @ID 

     FETCH NEXT FROM TableACursor INTO @ID 
    END; 

CLOSE TableACursor 
DEALLOCATE TableACursor 

-- Repeat for TableB 
DECLARE TableBCursor CURSOR 
    FOR SELECT ID FROM TableB 
OPEN TableBCursor 
    FETCH NEXT FROM TableBCursor INTO @ID 

    WHILE @@FETCH_STATUS = 0 
    BEGIN 
     INSERT INTO TableC (Name, TableType) SELECT Name, 'B' FROM TableB WHERE ID = @ID 
     INSERT INTO TableCChild(Name, Parent) SELECT Name, SCOPE_IDENTITY() FROM TableBChild WHERE Parent = @ID 
     FETCH NEXT FROM TableBCursor INTO @ID 
    END; 

CLOSE TableBCursor 
DEALLOCATE TableBCursor 

现在，我的问题（S）：

• 我一直被告知，光标是坏的。但我找不到另一种方式。我想知道是否有某种方式可以用CTE来做到这一点？
• 如果光标适合这种情况，我是怎么做的？有没有更好的方式去做我所做的事情？它看起来不太干，但我不是SQL专家。

最后，如果你想重新运行上面的查询，这里有一个小脚本来删除创建的表。

DROP TABLE TableAChild 
DROP TABLE TableBChild 
DROP TABLE TableCChild 

DROP TABLE TableA 
DROP TABLE TableB 
DROP TABLE TableC 

正确的结果应该是这样的：

Answer 1

这里是这样做没有一个鼠标或者其他RBAR类型的东西的一种方式。

ALTER TABLE TableC ADD LegacyID INT 
GO 

INSERT INTO TableC (TableType, Name, LegacyID) 
SELECT 'A', Name, ID 
FROM TableA 

INSERT TableCChild 
SELECT C.ID, AC.Name 
FROM TableAChild AC 
JOIN TableA A ON A.Id = AC.ID 
JOIN TableC C ON C.LegacyID = A.ID AND C.TableType = 'A' 

INSERT INTO TableC (TableType, Name, LegacyID) 
SELECT 'B', Name, ID 
FROM TableB 

INSERT TableCChild 
SELECT C.ID, AC.Name 
FROM TableBChild AC 
JOIN TableB A ON A.Id = AC.ID 
JOIN TableC C ON C.LegacyID = A.ID AND C.TableType = 'B' 

ALTER TABLE TableC DROP COLUMN LegacyID 
GO 

Answer 2

可以使用map表新老IDS基于一些关键的链接在一起。

在我的示例中，我使用的插入顺序为TableC。

1. 创建具有标识列的映射表。
2. 在TableC表基础上的TableAID和订单添加数据得到的地图
3. 使用TableA.id同样为了得到ROWNUMBER()并与映射表的标识列匹配，并更新所插入的ID的old_id在地图上匹配TableA.id与TableC.id。
4. 使用地图插入TableCChild表
5. 截断地图并冲洗并重复其他表格。

示例查询

CREATE TABLE #map(id int identity,new_id int,old_id int); 
INSERT INTO TableC 
(
    TableType, 
    Name 
)output inserted.id into #map(new_id) 
SELECT 'A',Name 
FROM TableA 
ORDER BY ID 


update m 
set m.old_id = ta.id 
FROM #map m 
inner join 
(
select row_number()OVER(order by id asc) rn,id 
from tableA 
)ta on ta.rn = m.id 

INSERT INTO TableCChild (Name, Parent) 
SELECT Name,M.new_ID 
FROM #Map M 
INNER JOIN TableAChild TA ON M.old_id = TA.Parent 

TRUNCATE TABLE #map 

INSERT INTO TableC 
(
    TableType, 
    Name 
)output inserted.id into #map(new_id) 
SELECT 'B',Name 
FROM TableB 
ORDER BY ID 

update m 
set m.old_id = tb.id 
FROM #map m 
inner join 
(
select row_number()OVER(order by id asc) rn,id 
from tableB 
)tb on tb.rn = m.id 

INSERT INTO TableCChild (Name, Parent) 
SELECT Name,M.new_ID 
FROM #Map M 
INNER JOIN TableBChild TB ON M.old_id = TB.Parent 

DROP TABLE #Map 

Answer 3

您可以使用merge作为Dr. OUTPUT or: How I Learned to Stop Worrying and Love the MERGE和this问题亚当Machanic描述来获得新的标识值，并在表变量旧的主键值和使用，当你插入之间的映射你的子表。

declare @T table(ID int, IDC int); 

merge dbo.TableC as C 
using dbo.TableA as A 
on 0 = 1 
when not matched by target then 
    insert (TableType, Name) values('A', A.Name) 
output A.ID, inserted.ID into @T(ID, IDC); 

insert into dbo.TableCChild(Parent, Name) 
select T.IDC, AC.Name 
from dbo.TableAChild as AC 
    inner join @T as T 
    on AC.Parent = T.ID; 

delete from @T; 

merge dbo.TableC as C 
using dbo.TableB as B 
on 0 = 1 
when not matched by target then 
    insert (TableType, Name) values('B', B.Name) 
output B.ID, inserted.ID into @T(ID, IDC); 

insert into dbo.TableCChild(Parent, Name) 
select T.IDC, BC.Name 
from dbo.TableBChild as BC 
    inner join @T as T 
    on BC.Parent = T.ID; 

SQL Fiddle

Answer 4

我只是写了下面的SQL这样做，如果该名称是在表B

INSERT INTO TableCChild 
    (
    Parent, 
    NAME 
) 
SELECT tc.ID, 
     ta.Name 
FROM TableAChild AS ta 
     JOIN TableA a 
      ON a.ID = ta.Parent 
     JOIN TableC AS tc 
      ON tc.Name = a.Name 
       AND tc.TableType = 'A' 
UNION 
SELECT tc.ID, 
     tb.Name 
FROM TableBChild AS tb 
     JOIN TableB b 
      ON b.ID = tb.Parent 
     JOIN TableC AS tc 
      ON tc.Name = b.Name 
       AND tc.TableType = 'B' 

TableA中独特的和独特的。如果名称不唯一，唯一的ID是唯一标识符，然后我会按建议添加LegacyId，然后代码如下

/* Change Table C to Have LegacyId as well and this is used to find the New Key for Inserts 
CREATE TABLE TableC 
(
    ID   INT NOT NULL IDENTITY PRIMARY KEY, 
    TableType  VARCHAR(1), 
    LegacyId  INT, 
    NAME   VARCHAR(30) 
); 
*/ 

INSERT INTO TableC (Name, TableType, LegacyId) 
SELECT DISTINCT NAME, 
     'A', 
     Id 
FROM TableA 
UNION 
SELECT DISTINCT NAME, 
     'B', 
     Id 
FROM TableB 

    INSERT INTO TableCChild 
     (
     Parent, 
     NAME 
    ) 
    SELECT tc.ID, 
      ta.Name 
    FROM TableAChild AS ta 
      JOIN TableA a 
       ON a.ID = ta.Parent 
      JOIN TableC AS tc 
       ON tc.LegacyId = a.Id 
        AND tc.TableType = 'A' 
    UNION 
    SELECT tc.ID, 
      tb.Name 
    FROM TableBChild AS tb 
      JOIN TableB b 
       ON b.ID = tb.Parent 
      JOIN TableC AS tc 
       ON tc.LegacyId = b.Id 
        AND tc.TableType = 'B' 

Answer 5

我们可以通过关闭Identity列直到完成插入，如下面的例子。

--Create the tables 

CREATE TABLE TableA 
(
    ID int not null identity primary key, 
    Name VARCHAR(30) 
); 

CREATE TABLE TableAChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_A FOREIGN KEY (Parent) REFERENCES TableA(ID) 
); 

CREATE TABLE TableB 
(
    ID int not null identity primary key, 
    Name VARCHAR(30) 
); 

CREATE TABLE TableBChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_B FOREIGN KEY (Parent) REFERENCES TableB(ID) 
); 

CREATE TABLE TableC 
(
    ID int not null identity primary key, 
    TableType VARCHAR(1), 
    Name VARCHAR(30) 
); 

CREATE TABLE TableCChild 
(
    ID int not null identity primary key, 
    Parent int not null, 
    Name VARCHAR(30), 
    CONSTRAINT FK_C FOREIGN KEY (Parent) REFERENCES TableC(ID) 
); 

-- Insert some test records.. 

INSERT INTO TableA (Name) Values ('A1') 
INSERT INTO TableAChild (Name, Parent) VALUES ('A1Child', SCOPE_IDENTITY()) 
INSERT INTO TableB (Name) Values ('B1') 
INSERT INTO TableBChild (Name, Parent) VALUES ('B1Child', SCOPE_IDENTITY()) 

SET IDENTITY_INSERT TableC ON 
INSERT INTO TableC(ID, TableType, Name) 
SELECT ID, 'A', Name FROM TableA 

INSERT INTO TableCChild(Parent, Name) 
SELECT Parent, Name FROM TableAChild 

DECLARE @MAXID INT 
SELECT @MAXID = MAX(ID) FROM TableC 
PRINT @MAXID 

SET IDENTITY_INSERT TableC ON 
INSERT INTO TableC(ID, TableType, Name) 
SELECT ID + @MAXID, 'B', Name FROM TableB 
SET IDENTITY_INSERT TableC OFF 

INSERT INTO TableCChild(Parent, Name) 
SELECT Parent + @MAXID, Name FROM TableBChild 

SET IDENTITY_INSERT TableC OFF 

SELECT * FROM TableC 
SELECT * FROM TableCChild 

DROP TABLE TableAChild 
DROP TABLE TableBChild 
DROP TABLE TableCChild 

DROP TABLE TableA 
DROP TABLE TableB 
DROP TABLE TableC 

Answer 6

如果你需要插入在第三个表表C和TableCChild供以后使用，然后它的罚款插入这些表中的数据，但如果你只需要此表的数据使用它在存储过程中暂时记录那么你也可以只使用前两个表来获得所需的结果。

select * from (
select a.ID,'A' as TableType,a.Name from TableA a inner join TableAChild b on a.ID=b.ID 
union 
select a.ID,'B' as TableType,a.Name from TableB a inner join TableBChild b on a.ID=b.ID) TableC 

同样得到TableCChild

select * from 
(
select b.ID,b.Parent,b.Name from TableA a inner join TableAChild b on a.ID=b.ID 
union 
select b.ID,b.Parent,b.Name from TableB a inner join TableBChild b on a.ID=b.ID) TableCChild 

如果你有在表C和TableCChild插入，那么你必须重新创建表C与ID和TABLETYPE主键，并关闭了ID列的身份。