Avatar billede it-dyret Nybegynder
11. november 2002 - 22:26 Der er 8 kommentarer og
1 løsning

Begrænsninger på Access

Jeg rådgiver i øjeblikket en gut i opbygning af en hjemmeside, hvor han har valgt at bruge Access... Hvornår er denne ikke tilstrækkelig?? Jeg tænker på hvilke konkrete begrænsninger, Access (2k) har inden for
* datamængde (har hørt at det er 2 gb)
* hastighed (lidt diffust formuleret, men findes der en eller andet tal for, hvor hurtig/god Access er i forhold til andre gænse db's på Nettet - f.eks. MySql)
* flerbrugere (hvor mange samtidige brugere kan Access håndtere - det kommer selvfølgelig an på antal søgninger, men hvis udgangspunktet er surfen rundt på den hjemmeside, hvor alt bliver genereret dynamisk. Og sidst men ikke mindst, hvad sker der, når man har nået grænsen?? Bliver folk smidt af, går det langsommere, kommer requests i kø eller hvad??)

Jeg har brug for nogle konkrete, målbare svar!

På forhånd tak!
Avatar billede terry Ekspert
12. november 2002 - 08:40 #1
2Gb Data, otherwise no limit to number of records.
max 255 connnections, although this will in practice be less. Access is NOT a server so it is slower than MS SQL and MySQL.
Avatar billede terry Ekspert
12. november 2002 - 08:43 #2
it-dyret, concrete and measurable answers! Well thats only possible once you have it working. You cant blame Access for bad programming :o)
Avatar billede terry Ekspert
12. november 2002 - 08:44 #3
Your comnment "Jeg har brug for nogle konkrete, målbare svar!" is more than likely the reason why your not getting many answers!
Avatar billede it-dyret Nybegynder
12. november 2002 - 09:44 #4
Hi Terry!

It seems one can always count on your in this category! :)

I have posed a similar question i the MySql category http://exp.dk/spm/282258 an got some pretty, good answers - I'm sure you can do the same... :) I'm familiar with programming and have a few years of experience with several languages. Consequently, I know that speed and so forth greatly depends on the programming!

But what if we take on the assumption "All things being equal"? How would you rate Access?? The dude I I'm advising have programmed almost an entire site - which is pretty comprehensive - all by himself, starting out with learning how to programme... Of cause this means that the code isn't top of the notch! What are the limits in accordance to Access?? And how much do you thing he would benefit from shifting to e.g. MySql - what would that do to the db-limitations (without correcting the shortcomings in the code)??
Avatar billede terry Ekspert
12. november 2002 - 10:20 #5
Hi again, just a pluck from your other question, comment form mahler!
(modsat Access, der er velegnet til amatører).

I do NOT agree with comment at all! There are thousands of proffesional sites out there based on Access. 
I agree that other DATABASE SERVERS (MySQL, ORACLE, MS SQL) will be faster and more stable but that does not mean that Access cant be used!

If you expect more than say 20 users reading/writing data at one time, or your data is expected to excede 2Gb  then I would suggest some other. Otherwise I would have nothing against using Access.

When I say 20 users, I mean those reading and writing data from the dB NOT those just viewing pages. Once a page is displayed then it SHOULD NOT use the dB.
Avatar billede it-dyret Nybegynder
12. november 2002 - 10:55 #6
Hi again, Terry!

I kind of expected Mahler's comment to provoke you! :)

Thanks for sharing your insight! One final question: what will happen, if the number of users exceed 20 or so?? Will the db become unstable, will it affect performance (speed), will the "extra" users be queued - or what?!?
Avatar billede terry Ekspert
12. november 2002 - 11:09 #7
If you ask Bill he will tell you that Access can actually tell you that you can have 255 connections but in practice it is a lot lower. I dont have much experience with Access on the WEB but I would expect that it wont be possible to make a connection if the limit is reached and I think this limit depends on many factors.
Access is prone to becoming unstable, but this is generally because connections are not closed.
It is VERY important to close connections and use error handling where needed.

I have also heard that dB requests do get buffered by the server but I must admit that I am not sure, and I would never program with that in mind anyway.
Avatar billede it-dyret Nybegynder
12. november 2002 - 11:15 #8
Thanks Terry!

I think this last piece of information completed the puzzle... I think my advice will be for the dude to continue using Access until he reaches its limitations and then persuade him to pay me for making him a full-scale pro solution :)
Avatar billede terry Ekspert
12. november 2002 - 11:19 #9
That sounds like a good idea!
and thanks:o)
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