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Michael 0'Sullivan

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

can someone explain dbase memo fields

Ive read that when you  edit a memo field in a dbase table that it
copies the text already there to a new memo field in the table,appends
what u entered to it and does not erase the orignal memo text. This
being the case then memo field will eventually grow out of hand, as they
are in my case. So how can u delete the memos that are now redundant,
packing does not seem to solve the problem, or can u remove these
useless memos, or is what I have read (the help file attached to
dbtfix.zip on the borland dbase support site) a load of rubbish
If I was to switch from dbase to another database then would anyone
suggest a more suitable database, I currently have 25 users and things
are beginning to slow

Thanks in advance.

 
Dmitr

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:can someone explain dbase memo fields


Try to read Inprise's paper on dbase file structure at
http://www.inprise.com/devsupport/delphi/ti_list/TI2821.html

Michael 0'Sullivan <mo_sulli...@hotmail.com> wrote

Quote
> Ive read that when you  edit a memo field in a dbase table that it
> copies the text already there to a new memo field in the table,appends
> what u entered to it and does not erase the orignal memo text. This
> being the case then memo field will eventually grow out of hand, as they
> are in my case. So how can u delete the memos that are now redundant,
> packing does not seem to solve the problem, or can u remove these
> useless memos, or is what I have read (the help file attached to
> dbtfix.zip on the borland dbase support site) a load of rubbish
> If I was to switch from dbase to another database then would anyone
> suggest a more suitable database, I currently have 25 users and things
> are beginning to slow

> Thanks in advance.

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:can someone explain dbase memo fields


Sundial Service

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:can someone explain dbase memo fields


Quote
> Michael 0'Sullivan <mo_sulli...@hotmail.com> wrote
> > If I was to switch from dbase to another database then would anyone
> > suggest a more suitable database, I currently have 25 users and
> > things are beginning to slow ...

It seems to me that the awkward handling of memo-fields is probably not
related to the speed.  Most of the time, performance delays are caused
by indexing, or by searches that are forced to scan through too many
records only to discard most or all of them.  

Bottlenecks in multi-user situations can also be caused by locking
delays, but most of the time I've seen them appear when an inefficient
application begins to saturate the network bandwidth... because all of
those records that are going to be discarded are still flowing down the
pipe.  Adding users simply brings the problem to a noticeable or crisis
point.

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:can someone explain dbase memo fields


Marco Roc

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:can someone explain dbase memo fields


On Tue, 03 Nov 1998 09:50:41 +0000, Michael 0'Sullivan

Quote
<mo_sulli...@hotmail.com> wrote:
>Ive read that when you  edit a memo field in a dbase table that it
>copies the text already there to a new memo field in the table,appends
>what u entered to it and does not erase the orignal memo text. This
>being the case then memo field will eventually grow out of hand, as they
>are in my case. So how can u delete the memos that are now redundant,
>packing does not seem to solve the problem, or can u remove these
>useless memos, or is what I have read (the help file attached to
>dbtfix.zip on the borland dbase support site) a load of rubbish
>If I was to switch from dbase to another database then would anyone
>suggest a more suitable database, I currently have 25 users and things
>are beginning to slow

I don't think slowness necessarily has to do with the memo fields.
Even if the memos are big, they are kept in a separate file (DBT).

Anyway, memos should be packed when you copy the data to another
table.  This should be done periodically, along with other ordinary
maintenance operations such as a physical pack of the tables (to
recover deleted record space) and a rebuild of indexes.

Regards,

--
Marco Rocci
MicroEra srl
Turin, Italy

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