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Posted by Shwetabh on 03/10/06 08:30
Erland Sommarskog wrote:
> > Now, what I have in mind is to create a table such that all Database is
> > stored in it. Since
> > the application will load only those fields into the labels which are
> > mapped, it wouldnt create a problem.
> > Now if I have 100 records in table 1 and 10 records in table 2, the
> > table 3 should have 110 records at the end of operation. This table
> > alone will be accessed by the application to do its work.
> > My question is how to do this? I mean how can I take the records from
> > table 1, put them in table 3, then take the records from table 2 and
> > put them in table 3 , and so on?
>
> To make a completely wild guess, this may be what you are looking for:
>
> INSERT tbl3(PART_NUM, PART_NAME, DESC1, DESC2)
> SELECT PART_NUM, PART_NAME, DESC1, DESC2
> FROM tbl1
>
> INSERT tbl3(PART_NUM, CAT_NUM, CAT_NAME, SDESC1, SDESC2)
> SELECT PART_NUM, CAT_NUM, CAT_NAME, SDESC1, SDESC2
> FROM tbl2 a
> WHERE NOT EXISTS (SELECT *
> FROM tbl3 WHERE a.PART_NUM = b.PART_NUM)
>
> UPDATE tbl3
> SET CAT_NUM = b.CAT_NUN,
> CAT_NAME = b.CAT_NAME,
> SDESC1 = b.SDESC1,
> SDESC2 = b.SDESC2
> FROM tbl3 a
> JOIN tbl2 b ON a.PART_NUM = b.PART_NUM
Thanks, but I found out another way to get the job done.
>
> >One more question, if I have a table in SQL,
> >can I alter a field to make it primary key?
> >Or do I have to to it while creating the table itself?
>
> You cannot alter the field to make it a PK, but you can alter the table
> to define a PK, if it does not have one. And PK can have more than one
> column.
Agreed, I can use
ALTER TABLE <tablename> ADD PRIMARY KEY (<fieldname>);
to alter the table and define a PK. But it works only if the
<fieldname> is
NOT NULL. Is there any way I can alter the table to make the field NOT
NULL?
>
>
> --
> Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
>
> Books Online for SQL Server 2005 at
> http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
> Books Online for SQL Server 2000 at
> http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
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