Insert rows in table while maintaining IDs - sql

Question

TABLEA
MasterCategoryID MasterCategoryDesc
1 Housing
1 Housing
1 Housing
2 Car
2 Car
2 Car
3 Shop
TABLEB
ID Description
1 Home
2 Home
3 Plane
4 Car
INSERT into TableA
(
[MasterCategoryID]
[MasterCategoryDesc]
)
Select
case when (Description) not in (select MasterCategoryDesc from TableA)
then (select max(MasterCategoryID)+1 from TableA)
else (select top 1 MasterCategoryID from TableA where MasterCategoryDesc = Description)
end as [MasterCategoryID]
,Description as MasterCategoryDesc
from TableB
I want to enter rows using SQL/Stored Procedure from tableB to tableA. for example when inserting first row 'Home' it does not exist in MastercategoryDesc therefore will insert '4' in MasterCategoryID. Second row should keep the '4' again in MasterCategoryID.
The code below does it however after the first row the MastercategoryID remains the same for all rows. I Dont know how to keep track of ids while inserting the new rows.
p.s. Pls do not reply by saying i need to use IDENTITY() index. I have to keep the table structure the same and cannot change it. thanks

Answer 1

Create a new table your_table with fields x_MasterCategoryDesc ,x_SubCategoryDesc
Insert all your values in that table and the run the below SP.
CREATE PROCEDURE x_experiment
AS
BEGIN
IF object_id('TEMPDB..#TABLES') IS NOT NULL
BEGIN
DROP TABLE #TABLES
END
DECLARE #ROWCOUNT INT
DECLARE #ROWINDEX INT =0,
#MasterCategoryDesc VARCHAR(256),
#SubCategoryDesc VARCHAR(256)
select IDENTITY(int,1,1) as ROWID,*
into #TABLES
From your_table
SELECT #ROWCOUNT=COUNT(*) from #TABLES --where ROWID between 51 and 100
WHILE (#ROWINDEX<#ROWCOUNT)
BEGIN
set #ROWINDEX=#ROWINDEX+1
Select
#MasterCategoryDesc=x_MasterCategoryDesc,
#SubCategoryDesc=x_SubCategoryDesc
from #TABLES t
where rowid = #ROWINDEX
INSERT into Table1
([MasterCategoryID], [MasterCategoryDesc], [SubCategoryDesc], [SubCategoryID])
select TOP 1
case when #MasterCategoryDesc not in (select [MasterCategoryDesc] from Table1)
then (select max([MasterCategoryID])+1 from Table1)
else (select distinct max([MasterCategoryID]) from Table1
where [MasterCategoryDesc]=#MasterCategoryDesc
group by [MasterCategoryID])
end as [MasterCategoryID]
,#MasterCategoryDesc as [MasterCategoryDesc]
,#SubCategoryDesc as [SubCategoryDesc]
,case when #SubCategoryDesc not in (select [SubCategoryDesc] from Table1)
then (select max([SubCategoryID])+1 from Table1 )
else (select max([SubCategoryID]) from Table1
where [SubCategoryDesc]=#SubCategoryDesc
group by [SubCategoryID])
end as [SubCategoryID]
from Table1
END
select * from Table1 order by MasterCategoryID
END
GO
exec x_experiment --SP Execute
SQL FIDDLE

Answer 2

Use a CURSOR to do the work. The cursor loops through each row of TableA and the MasterCategoryID increases if it is not found in TableB. This happens before the next row of TableA is loaded into the cursor ...
DECLARE #ID int
DECLARE #Description VARCHAR(MAX)
DECLARE my_cursor CURSOR FOR
SELECT ID, Description FROM TableB
OPEN my_cursor
FETCH NEXT FROM my_cursor
INTO #ID, #Description
WHILE ##FETCH_STATUS = 0
BEGIN
INSERT into TableA(MasterCategoryID, MasterCategoryDesc)
SELECT CASE WHEN #Description NOT IN (SELECT MasterCategoryDesc FROM TableA)
THEN (SELECT MAX(MasterCategoryID)+1 FROM TableA)
ELSE (SELECT TOP 1 MasterCategoryID
FROM TableA
WHERE MasterCategoryDesc = #Description)
END AS MasterCategoryID, Description as MasterCategoryDesc
FROM TableB
WHERE ID = #ID
FETCH NEXT FROM my_cursor
INTO #ID, #Description
END

Answer 3

Your data structure leaves something to be desired. You shouldn't have a master id column that has repeated values.
But you can still do what you want:
INSERT into TableA ([MasterCategoryID], [MasterCategoryDesc])
Select coalesce(a.MasterCategoryId,
amax.maxid + row_number() over (partition by (a.MasterCategoryId) order by b.id)
),
coalesce(a.MasterCategoryDesc, b.desc)
from TableB b left outer join
(select desc, max(MasterCaegoryId) as maxid
from TableA a
group by desc
) a
on b.desc = a.desc left outer join
(select max(MasterCategoryID) as maxid
from TableA
) amax
The idea is to take the information from the master table when it is available. When not available, then MasterCategoryId will be NULL. A new id is calculated, using row_number() to generate sequential numbers. These are then added to the previous maximum id.