replication technique

Hello,
I read serveral articles about the mechanism of replication from a sql
server 2000 database on
desktop with an mobile device running windows mobile.
I want to remark my understanding fo the replication mechanism and wanted to
ask you if you
could give me feedback if I understand it in a correct way.
-----
1) First of all I create a publication - which is a collection of articles -
rows. It is
possible to define certain tables and rows for publication.
2) After the publication a windows ce-based application can call the methods
of the SQL Server
Ce Replication object to subscribe to the publication. When the mobile
application has executed
the subscription the initial snapshot of the published table is stored on
the mobile device and
so the database file is created on the device.
3) The subscription database on the device can then be updated by
synchronzing it with the desktop
database. For that the synchronisation is always intiated by the device. For
that the SQL Server CE
Client Agent extracts all modified rows from the subscription database put
these rows in a message
file and sends it over HTTP to the SQL Server CE Server Agent. The SQL
Server CE Server Agent
creates a new message file on the desktop where the IIS is running and
writes in that file the
modified rows which are sent by the SQL Server CE Client Agent.Then the SQL
Server CE Server Agent
initiates the SQL Server Reconciler process. The SQL Server Reconciler
Process loads the SQL Server CE
Replication Provider which reads the message file which was created by the
SQL Server CE Server Agent
and apply the changes to the publisher database. The SQL Server CE
Replication Provider informs the SQL Server
Reconciler about the changes which were made in the subscription
database.The SQL Server Reconciler
also solves conflicts if more than one subscriber or publisher updates the
same record.
On the other hand the SQL Server Reconciler informs the SQL Server CE
Replication Provider of
changes which occured at the publisher database. The SQL Server CE
Replication writes this
information - especially the modified rows - to an output message file.
After the Reconciler
process is completed the SQL Server CE Server Agent locates the the output
message file reads
the information and transfer it to the SQL Server CE Client Agent which
apply the changes from
the output message file to the subscription databse on the windows ce device.
-----
a) Are these steps correct or have I forgotten anything important or have I
understand something
wrong?
b) What I have to imagine behind the SQL Server CE Client Agent, the SQL
Server CE Server Agent,
SQL Server Reconciler and the SQL Server CE Replication Provider? What are
these terms exactly?
c) When I publish a database, especially tables in the enterprise manager
the tables get automatically
a row guid. What part plays these row guid's in my above mentioned
replication process?
d) The Replication Mechanism uses static and dynamic filtering. Is it right
that the dynamic filter
could not use on the application layer? - means that it is not possiblt to
replicate for example
the information according to the user which is currently logged in the
application? - I think it
is only possible to synchronize according to a certain device especially
certain host, is that right?
I know this is a extensive posting but I would appreciate it very much if
anybody find time to
answer me my questions. :-/
Regards.
patrick
answers inline
--
Hilary Cotter
Looking for a SQL Server replication book?
http://www.nwsu.com/0974973602.html
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http://www.indexserverfaq.com
"pat" <pat@.discussions.microsoft.com> wrote in message
news:273513F0-8240-4E1A-9598-9ED04BC448CE@.microsoft.com...
> Hello,
> I read serveral articles about the mechanism of replication from a sql
> server 2000 database on
> desktop with an mobile device running windows mobile.
> I want to remark my understanding fo the replication mechanism and wanted
> to
> ask you if you
> could give me feedback if I understand it in a correct way.
> -----
> 1) First of all I create a publication - which is a collection of
> articles -
> rows. It is
> possible to define certain tables and rows for publication.
Yes, you will need to set up a merge publication. When you say rows for
publication you mean horizontal filtering.
> 2) After the publication a windows ce-based application can call the
> methods
> of the SQL Server
> Ce Replication object to subscribe to the publication. When the mobile
> application has executed
> the subscription the initial snapshot of the published table is stored on
> the mobile device and
> so the database file is created on the device.
Yes, you will code something using vb or vc embedded or the .Net compact
framework to pull a merge subscription. This will use a SQL CE database on
your PocketPC.
> 3) The subscription database on the device can then be updated by
> synchronzing it with the desktop
> database. For that the synchronisation is always intiated by the device.
> For
> that the SQL Server CE
> Client Agent extracts all modified rows from the subscription database put
> these rows in a message
> file and sends it over HTTP to the SQL Server CE Server Agent. The SQL
> Server CE Server Agent
> creates a new message file on the desktop where the IIS is running and
> writes in that file the
> modified rows which are sent by the SQL Server CE Client Agent.Then the
> SQL
> Server CE Server Agent
> initiates the SQL Server Reconciler process. The SQL Server Reconciler
> Process loads the SQL Server CE
> Replication Provider which reads the message file which was created by the
> SQL Server CE Server Agent
> and apply the changes to the publisher database. The SQL Server CE
> Replication Provider informs the SQL Server
> Reconciler about the changes which were made in the subscription
> database.The SQL Server Reconciler
> also solves conflicts if more than one subscriber or publisher updates the
> same record.
> On the other hand the SQL Server Reconciler informs the SQL Server CE
> Replication Provider of
> changes which occured at the publisher database. The SQL Server CE
> Replication writes this
> information - especially the modified rows - to an output message file.
> After the Reconciler
> process is completed the SQL Server CE Server Agent locates the the output
> message file reads
> the information and transfer it to the SQL Server CE Client Agent which
> apply the changes from
> the output message file to the subscription databse on the windows ce
> device.
>
This is basically it.
> -----
> a) Are these steps correct or have I forgotten anything important or have
> I
> understand something
> wrong?
that's basically it

> b) What I have to imagine behind the SQL Server CE Client Agent, the SQL
> Server CE Server Agent,
> SQL Server Reconciler and the SQL Server CE Replication Provider? What are
> these terms exactly?
> c) When I publish a database, especially tables in the enterprise manager
> the tables get automatically
> a row guid. What part plays these row guid's in my above mentioned
> replication process?
it uniquely identifys each row, so SQL Server can figure out which row has
changed or needs changing.

> d) The Replication Mechanism uses static and dynamic filtering. Is it
> right
> that the dynamic filter
> could not use on the application layer? - means that it is not possiblt to
> replicate for example
> the information according to the user which is currently logged in the
> application? - I think it
> is only possible to synchronize according to a certain device especially
> certain host, is that right?
>
No, you define your filter on the publication. I don't believe you can
filter your subscribers.

> I know this is a extensive posting but I would appreciate it very much if
> anybody find time to
> answer me my questions. :-/
> Regards.
> patrick
>
|||Hello,
Thank you very much for your reply but few things are still unclear:
1) Why do I need the row guid? - the changed rows are saved in a file and
are sent to the SQL Server CE Server Agent, so he knows which rows were
modified when he looks into the message file. Why does he need then a row
guid?
2) The SQL Server CE Client Agent, the SQL, Server CE Server Agent, SQL
Server Reconciler and the SQL Server CE Replication Provider - are these
processes or components or parts of the os? what I have to imagine behind
these terms?
3) Referring to dynamic filtering I thought it is possible to synchronize
after a certain host on the mobile device? - What can I then realize with
dynamic filterin?
(static filtering is when I define some rows or columns or tables which I
can then synchronize or?)
Hopefully you could answer me once more.
regards
patrick
3)
|||Hi,
Thank you very much for your reply but unfortunately few things are unclear:
1)Why do I need this row guid's, because the SQL Server CE Server Agent
reads the modified rows from the message file which is sent by the SQL
Server CE Client Agent and so the SQL Server CE Replication Provider knows
what rows he has to modify. So why do I neet this row guids?
2)Tthe SQL Server CE Client Agent, the SQL Server CE Server Agent, SQL
Server Reconciler and the SQL Server CE Replication Provider - what do I have
to imagene behind these terms? Are these processes or components or part of
the os or anyting else?
3)Referring to the filtering. So it is not possible to define a filter
according to a certain host on a mobile device? - The static filtering allows
to define some rows or columns or tables which can be modified, but then for
what is the dynamic filtering?
regards
patrick
|||hi,
is it possible to answer me the last time on my three posted questions?
regards
patrick
sql