[AccessD] Property Value is too large

[Jim Dettman]

 It would not be an easy thing to do because of the architecture of JET.

 Because of the size of pointers within the page, it would require substantial changes.  I don't remember all the in's and outs of it, but doubling from 2048 to 4096 was only doable because nothing really changed. A page size of 4096 was still within the range of things like field offsets.  There's also page addressing and locking that would tie into it I would think. Those things are also why we are limited on the overall size of the database.

 JET was never meant to be a sophisticated RDBMS, so it's lacking things like page management (knowing which pages are free/busy, and how much space they have), inability to split pages, etc.   That why there are things LVP's (Long Value Pages) for storing OLE and Memo fields, and JET simply goes after the last page in a table when it wants to add something.

 It's possible that there have been internal changes with ACE because nothing has been documented since JET 4.0, and even then, there wasn't much documentation.   Just little hints and what not spread in various white papers and MSKB articles.

Jim.

-----Original Message-----
From: AccessD On Behalf Of John Colby
Sent: Monday, May 15, 2023 1:06 PM
To: Access Developers discussion and problem solving <accessd at databaseadvisors.com>
Subject: Re: [AccessD] Property Value is too large

So what if we design a page on disk as 64K?

On Mon, May 15, 2023 at 12:49 PM Jim Dettman via AccessD <
accessd at databaseadvisors.com> wrote:

> << It turns out that there is a limit to the size of a table definition
> that
> Acceess can store (2KB ? )>>
>
>  Yes.  JET/ACE doesn't have split pages, so a table def must fit on a
> single
> page of 4096 bytes.  With Unicode and text taking up 2 bytes, that hovers
> around 2000 bytes in general.
>
>  "Record too large" is the corresponding error for data.
>
> Jim.
>
> -----Original Message-----
> From: AccessD On Behalf Of Stuart McLachlan
> Sent: Sunday, May 14, 2023 6:27 PM
> To: Access Developers discussion and problem solving
> <accessd at databaseadvisors.com>
> Subject: [AccessD] Property Value is too large
>
> First time I've run across this in 30 years. I've been developing contantly
> in  Access since
> 1993 and never seen it before.
>
> When trying to add another field to a table, I got the message "Property
> Value is too Large"
> and couldn''t save the change. In fact I couldn't even save the table if I
> deleted a field in it - I
> got the same error
>
> This particular , table (which I did not design - but a couple of people
> here might recognise)
> had 178 fields!   Many of the fields had "Lookup" Comboxes specified
> containing long SQL
> select statements. Also a load of long "Descriptions".
>
> It turns out that there is a limit to the size of a table definition that
> Acceess can store (2KB ? )
> and  this is not just for the table structure , it  includes the Lookup and
> Description data for
> each field and the Index definitions. ( there are 20 indexes specified for
> this table, even just
> trying to delete one and saving the table gave the same message).
>
> After I cleaned a lot of the garbage out (primarily Lookup comboxes),  I
> was
> able to add the
> field.
>
> Yet another reason why I dislike specifying anything other than the default
> for field display in
> the table design - IMNSHO, that's NOT where user interfaces should be
> specified!!!
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-- 
John W. Colby
Colby Consulting
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