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asa mobile/wireless

6 posts in General Discussion Last posting was on 2003-06-06 14:21:34.0Z
Doug Stone Posted on 2003-06-04 18:00:56.0Z
From: "Doug Stone" <nospamdstone@res-q.com>
Subject: asa mobile/wireless
Date: Wed, 4 Jun 2003 11:00:56 -0700
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Article PK: 3399

We are thinking about creating a mobile/wireless option for our hospital
scheduling application.

When a disconnected mobile user makes schedule changes on her handheld, and
then later sync's with the main database, how does the database sync process
decide which scheduling records (mobile or main) have precedence?

In other words, how does one setup the sync operation so that the correct
scheduling records will be in the main database after the sync operation is
complete?

Do we need to have a "date last modified" column in every table that might
be sync'd?

Thanks,
Doug


Robert Waywell Posted on 2003-06-05 13:34:02.0Z
From: "Robert Waywell" <nospam_rwaywell@ianywhere.com>
References: <ezriFOsKDHA.221@forums-1-dub>
Subject: Re: asa mobile/wireless
Date: Thu, 5 Jun 2003 09:34:02 -0400
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Article PK: 3405

A "date/time last modified" is definitely the most common tool for conflict
detection/resolution. You could have arbitrary rules such as 'cons' always
wins, or remote always win, but timestamp is generally the best choice.


--
-----------------------------------------------
Robert Waywell
Sybase Adaptive Server Anywhere Developer - Version 8
Sybase Certified Professional

Sybase's iAnywhere Solutions

Please respond ONLY to newsgroup

EBF's and Patches: http://downloads.sybase.com
choose SQL Anywhere Studio >> change 'time frame' to all

To Submit Bug Reports: http://casexpress.sybase.com/cx/cx.stm

SQL Anywhere Studio Supported Platforms and Support Status
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Whitepapers, TechDocs, and bug fixes are all available through the iAnywhere
Developer Community at www.ianywhere.com/developer

"Doug Stone" <nospamdstone@res-q.com> wrote in message
news:ezriFOsKDHA.221@forums-1-dub...
>
> We are thinking about creating a mobile/wireless option for our hospital
> scheduling application.
>
> When a disconnected mobile user makes schedule changes on her handheld,
and
> then later sync's with the main database, how does the database sync
process
> decide which scheduling records (mobile or main) have precedence?
>
> In other words, how does one setup the sync operation so that the correct
> scheduling records will be in the main database after the sync operation
is
> complete?
>
> Do we need to have a "date last modified" column in every table that might
> be sync'd?
>
> Thanks,
> Doug
>
>


Doug Stone Posted on 2003-06-05 17:07:43.0Z
From: "Doug Stone" <nospamdstone@res-q.com>
References: <ezriFOsKDHA.221@forums-1-dub> <#akuZg2KDHA.317@forums-2-dub>
Subject: Re: asa mobile/wireless
Date: Thu, 5 Jun 2003 10:07:43 -0700
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Robert, does ASA maintain, internally, the date/time a record was last
modified?
Thanks,
Doug

"Robert Waywell" <nospam_rwaywell@ianywhere.com> wrote in message
news:%23akuZg2KDHA.317@forums-2-dub...
> A "date/time last modified" is definitely the most common tool for
conflict
> detection/resolution. You could have arbitrary rules such as 'cons' always
> wins, or remote always win, but timestamp is generally the best choice.
>
>
> --
> -----------------------------------------------
> Robert Waywell
> Sybase Adaptive Server Anywhere Developer - Version 8
> Sybase Certified Professional
>
> Sybase's iAnywhere Solutions
>
> Please respond ONLY to newsgroup
>
> EBF's and Patches: http://downloads.sybase.com
> choose SQL Anywhere Studio >> change 'time frame' to all
>
> To Submit Bug Reports: http://casexpress.sybase.com/cx/cx.stm
>
> SQL Anywhere Studio Supported Platforms and Support Status
> http://my.sybase.com/detail?id=1002288
>
> Whitepapers, TechDocs, and bug fixes are all available through the
iAnywhere
> Developer Community at www.ianywhere.com/developer
>
> "Doug Stone" <nospamdstone@res-q.com> wrote in message
> news:ezriFOsKDHA.221@forums-1-dub...
> >
> > We are thinking about creating a mobile/wireless option for our hospital
> > scheduling application.
> >
> > When a disconnected mobile user makes schedule changes on her handheld,
> and
> > then later sync's with the main database, how does the database sync
> process
> > decide which scheduling records (mobile or main) have precedence?
> >
> > In other words, how does one setup the sync operation so that the
correct
> > scheduling records will be in the main database after the sync operation
> is
> > complete?
> >
> > Do we need to have a "date last modified" column in every table that
might
> > be sync'd?
> >
> > Thanks,
> > Doug
> >
> >
>
>


Breck Carter [TeamSybase] Posted on 2003-06-05 19:43:37.0Z
From: "Breck Carter [TeamSybase]" <NOSPAM__bcarter@risingroad.com>
Subject: Re: asa mobile/wireless
Date: Thu, 05 Jun 2003 15:43:37 -0400
Organization: RisingRoad Professional Services
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Article PK: 3409

No, you need to add a column

last_updated TIMESTAMP NOT NULL DEFAULT TIMESTAMP

which will be automatically set on every INSERT and UPDATE, without
you having to add any client-side or trigger logic.

Breck

On Thu, 5 Jun 2003 10:07:43 -0700, "Doug Stone"

<nospamdstone@res-q.com> wrote:

>Robert, does ASA maintain, internally, the date/time a record was last
>modified?
>Thanks,
>Doug
>
>
>"Robert Waywell" <nospam_rwaywell@ianywhere.com> wrote in message
>news:%23akuZg2KDHA.317@forums-2-dub...
>> A "date/time last modified" is definitely the most common tool for
>conflict
>> detection/resolution. You could have arbitrary rules such as 'cons' always
>> wins, or remote always win, but timestamp is generally the best choice.
>>
>>
>> --
>> -----------------------------------------------
>> Robert Waywell
>> Sybase Adaptive Server Anywhere Developer - Version 8
>> Sybase Certified Professional
>>
>> Sybase's iAnywhere Solutions
>>
>> Please respond ONLY to newsgroup
>>
>> EBF's and Patches: http://downloads.sybase.com
>> choose SQL Anywhere Studio >> change 'time frame' to all
>>
>> To Submit Bug Reports: http://casexpress.sybase.com/cx/cx.stm
>>
>> SQL Anywhere Studio Supported Platforms and Support Status
>> http://my.sybase.com/detail?id=1002288
>>
>> Whitepapers, TechDocs, and bug fixes are all available through the
>iAnywhere
>> Developer Community at www.ianywhere.com/developer
>>
>> "Doug Stone" <nospamdstone@res-q.com> wrote in message
>> news:ezriFOsKDHA.221@forums-1-dub...
>> >
>> > We are thinking about creating a mobile/wireless option for our hospital
>> > scheduling application.
>> >
>> > When a disconnected mobile user makes schedule changes on her handheld,
>> and
>> > then later sync's with the main database, how does the database sync
>> process
>> > decide which scheduling records (mobile or main) have precedence?
>> >
>> > In other words, how does one setup the sync operation so that the
>correct
>> > scheduling records will be in the main database after the sync operation
>> is
>> > complete?
>> >
>> > Do we need to have a "date last modified" column in every table that
>might
>> > be sync'd?
>> >
>> > Thanks,
>> > Doug
>> >
>> >
>>
>>
>

bcarter@risingroad.com
Mobile and Distributed Enterprise Database Applications
http://www.risingroad.com


Shuchit Velkar Posted on 2003-06-06 01:34:05.0Z
Subject: Re: asa mobile/wireless
From: Shuchit Velkar <xxx@xxx.net>
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"Robert Waywell" <nospam_rwaywell@ianywhere.com> wrote in
news:#akuZg2KDHA.317@forums-2-dub:

> A "date/time last modified" is definitely the most common tool for
> conflict detection/resolution. You could have arbitrary rules such as
> 'cons' always wins, or remote always win, but timestamp is generally
> the best choice.
>
>

First, I assuming that we are talking about a MobiLink synchronization
system and not SQL Remote.

I would add to Rob's reply that the "last modified" datetime column is
required only on the consolidated (the master database). On the remote
databases, ASA will automatically keep track of what changes are being
done to the synchronizing tables and upload them to the consolidated
whenever you synchronize.


As for detecting updates to the same record in different databases, there
is a whole conflict detection and resolution mechanism. Conflict detection
is mostly automatic (You need to write one script for each table to tell
MobiLink which table/columns to use from the consolidated). You would
write SQL/Java/.NET scripts to define how the conflict should be handled
according to your business rules. You will have access to the current
values in the consolidated, the values from the remote before changes were
done and values from the remote after the changes. Based on this your
script can decide to choose one set of the values or merge the three sets
in what manner you think appropriate.


Both the above appy, whether you UltraLite or ASA on your handheld. ASA is
only valid for Windows CE devices.

--
Shuchit Velkar
iAnywhere Solutions
Professional Services
Please only post to the newsgroup

EBFs and Whitepapers
http://www.ianywhere.com/developer


Shuchit Velkar Posted on 2003-06-06 14:21:34.0Z
Subject: Re: asa mobile/wireless
From: Shuchit Velkar <xxx@xxx.net>
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Shuchit Velkar <xxx@xxx.net> wrote in
news:Xns9391DAC363813svelkarNOsybaseSPAMc@192.138.151.106:

> "Robert Waywell" <nospam_rwaywell@ianywhere.com> wrote in
> news:#akuZg2KDHA.317@forums-2-dub:
>
>> A "date/time last modified" is definitely the most common tool for
>> conflict detection/resolution. You could have arbitrary rules such as
>> 'cons' always wins, or remote always win, but timestamp is generally
>> the best choice.
>>
>>
>
> First, I assuming that we are talking about a MobiLink synchronization
> system and not SQL Remote.
>
> I would add to Rob's reply that the "last modified" datetime column is
> required only on the consolidated (the master database). On the remote
> databases, ASA will automatically keep track of what changes are being
> done to the synchronizing tables and upload them to the consolidated
> whenever you synchronize.
>
>
> As for detecting updates to the same record in different databases,
> there is a whole conflict detection and resolution mechanism. Conflict
> detection is mostly automatic (You need to write one script for each
> table to tell MobiLink which table/columns to use from the
> consolidated). You would write SQL/Java/.NET scripts to define how
> the conflict should be handled according to your business rules. You
> will have access to the current values in the consolidated, the values
> from the remote before changes were done and values from the remote
> after the changes. Based on this your script can decide to choose one
> set of the values or merge the three sets in what manner you think
> appropriate.
>
>
> Both the above appy, whether you UltraLite or ASA on your handheld.
> ASA is only valid for Windows CE devices.
>

As Rob points out, if your business logic for conflict resolution depends
on when the record was last updated, then you would need the datetimes
on both the remote and the consolidated. You do need to make sure
that the clocks of the consolidated and the remote are in sync.

--
Shuchit Velkar
iAnywhere Solutions
Professional Services
Please only post to the newsgroup

EBFs and Whitepapers
http://www.ianywhere.com/developer