Re: [slang-users] SLAG update and information.

[Ben Duncan <ben@xxxxxxxxxxxxxxxxxx>]

That's the beauty. It IS linux based. SLAG and any work I do thereof
is going to have a reverse Bill Gates Attitude - *NIX only for the
Server side ;-> (I'll use some sort of thin client for Winsnot machines).

Paul Boekholt wrote:
> > Accounting programs usually can and do have the files open multiple
> > times (And A/R aging routine is a prime example).
>
> Can you expand on this?  Does A/R aging open a file multiple times
> read-only, or read/write? 

It depends. Lets say you are applying a payment on accounts in real time.
First, the Payment would get posted to the file (write to file and held open in
 a buffer). Then you would read the AR documents it applied to as another
open to the AR Open file. If it was a "receivable", apply the amount to the
AR document write it out, reduce the amount available on the Payment RECORD,
read the NEXT document it applied to, apply any amounts and continue this cycle
until no more monies were left on the PAYMENT side and then write it back out.

So in the case it would be 2 or more opens in Read Write mode, but not an
exclusive FILE locking, but a Record/Row lock.

ONLY exclusive file locking gets implemented in the case of BATCH updated.
Say you needed to have an across the BOARD price increase in your inventory items.
Then you would do an exclusive LOCK at the file level, read each and every
item and update it's price, then release the FILE lock.

Other times such as cross referencing (Doing a customer Lookup), the Lookup files
maybe the customer file opened as read only (for starts and read next's), but the
primary file is for the "UPDATE".


> > Now all I have to do is come up with a embedded database engine for SLAG.
> > I am looking at possible adapting GDBM to a Multi Value environment and use my
> > own locking semaphore routines.
>
> What OS does the Department of Wildlife use?  If they use windows,
> you probably can't use tdb.  If you need to open a file multiple times
> read-only in one process, then if you don't need concurrency, use GDBM.
> Otherwise, ask the tdb maintainers to fix it (maybe it's already fixed
> in the Samba version?).  If you need to open a file multiple times
> read-write in one process, you should look for some other database.  If
> you don't need to open a file multiple times read-write in one process,
> but you do need concurrency, then try to get the Department of Wildlife
> to switch to Linux, or try to get someone to port tdb to Windows.
>
> _______________________________________________
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--
Ben Duncan   - VersAccounting Software LLC 336 Elton Road  Jackson MS, 39212
"Never attribute to malice, that which can be adequately explained by stupidity"
       - Hanlon's Razor


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