LS.

What would be the proper way to create a SQL script that
-checks if a table exists otherwise creates it
-checks if (if the table is there) a field exists otherwise creates it
-checks if (if the table and field are there) a field type, length etc are
correct exists otherwise corrects it
-checks if (if the table is there) an index exists otherwise creates it
and doesn't loose the data the table already contains.

dbIsam 3.30

Regards, Harry

...or is this better to be done in object pascal?

"Harry de Boer" <harry@staaf.nl> schreef in bericht
news:05EFEAA9-86AD-4E5D-BDF6-CF0452E2BDDD@news.elevatesoft.com...
> LS.
>
> What would be the proper way to create a SQL script that
> -checks if a table exists otherwise creates it
> -checks if (if the table is there) a field exists otherwise creates it
> -checks if (if the table and field are there) a field type, length etc are
> correct exists otherwise corrects it
> -checks if (if the table is there) an index exists otherwise creates it
> and doesn't loose the data the table already contains.
>
> dbIsam 3.30
>
> Regards, Harry
>
>

Harry


I can't remember when some features made it into DBISAM. Certainly on V4 you should be able to do things like

CREATE TABLE IF NOT EXISTS ...

ALTER TABLE IF EXISTS ....

REDEFINE COLUMN IF EXISTS ....

ADD COLUMN IF NOT EXISTS

The thing you can't do (or I don't know how) is along the lines of

CREATE TABLE IF NOT EXISTS else ALTER TABLE .....


Roy Lambert

Harry,

<< What would be the proper way to create a SQL script that
-checks if a table exists otherwise creates it
-checks if (if the table is there) a field exists otherwise creates it
-checks if (if the table and field are there) a field type, length etc are
correct exists otherwise corrects it
-checks if (if the table is there) an index exists otherwise creates it and
doesn't loose the data the table already contains. >>

With 3.x, I don't think you can use the EXISTS keyword with columns, so
you'll probably have to resort to OP to code the alter table.  Check out the
Restructuring Tables topic in the manual for more information.

--
Tim Young
Elevate Software
www.elevatesoft.com

Harry

You could look at Peter Mora's DbisamDsnTbl component which
I think can do all those things with minimum effort on your
part.

It uses Pascal as V3 SQL could not do it.

Search the binaries ng for it.

I have used it extensively to manage database restructuring
in DBISAM V3 and V4

Sample code...

 with A_DbisamDsnTbl do
 begin
   if not Exists then
     MakeTable;
   else if not CompareStructure then
     UpdateTable;
 end;

Now, if only ....

Malcolm

Thanks

Sounds like what I need. I will look into it.

Regards, Harry


"Malcolm" <malcolm@spam.will.bounce> schreef in bericht
news:60F4767F-98F9-483B-806A-2E2879063A9E@news.elevatesoft.com...
> Harry
>
> You could look at Peter Mora's DbisamDsnTbl component which
> I think can do all those things with minimum effort on your
> part.
>
> It uses Pascal as V3 SQL could not do it.
>
> Search the binaries ng for it.
>
> I have used it extensively to manage database restructuring
> in DBISAM V3 and V4
>
> Sample code...
>
>   with A_DbisamDsnTbl do
>   begin
>     if not Exists then
>       MakeTable;
>     else if not CompareStructure then
>       UpdateTable;
>   end;
>
> Now, if only ....
>
> Malcolm