Database

27-Jan-09 9:52

Sounds like you need transactional replication. That replication works so that first a snapshot is taken from the source to get the current situation for the publication. This is delivered to subscriber(s). After that modifications to publication are gathered at the source and they are delivered to subscribers at configurable intervals.

Just a warning. This works fine when the transfer is only from source to target. If it's bi-directional so that the same data can be modified on all nodes, you will easily get into trouble because of update conflicts.

Finally to your question. The bandwith depends at least on these things:

replication interval, the smaller the interval is, the less modifications need to be transferred
amount of changes, how much data is changed (inserted, updated and deleted) at the source between two transfers
characteristics of the changed data, if it is mainly numbers or dates, it requires less bandwith than for example longer varchar data not to mention BLOB data
reliability of the connection, if the data must be sent several times, it will affect. Also it affects if the data is buffered on distributor because connection isn't available.

So as you see, it's quite impossible to give any accurate bandwith, but I believe that if you investigate those things, you'll get a clear picture on the data amounts.

Also why not build a test replication environment, replicate the actual data and use replication monitor in SQL Server and performance monitor to see what kind of amounts are transferred.

BTW, I noticed that you're new to CodeProject, welcome! Just to inform you that we have a voting system you can use if you want. Each reply can be marked good/bad and if the type of the post isn't reply, you'll see voting options in the lower right corner of the post from 1 (bad) to 5 (good). Usually these are used to indicate if the answers given to a person were helpful or not.

Mika

The need to optimize rises from a bad design.My articles[^]

a count query

sana1723-Jan-09 10:37

sana17

23-Jan-09 10:37

hello,
i have to ask for a sql query:

scenerio:
i have two tables CHATROOMS AND MEMBERS

CHATROOMS table contain columns (ROOM_ID(pk) and ROOM_NAME)
MEMBERS table contain columns (MEMBER_ID, ROOM_ID(fk))

now i have a gridview control in which i have to display all ROOM_IDs along with members init.

like:

ROOM_ID | MEMBERS
room1 | 5
room2 | 7
room3 | 6
room5 | 2

i want a single query for it coz i am binding data to gridview using SQLDATASOURCE control in ASP.net(C#)

the query i am trying is not working!
my query is:
select count(*) as total from MEMBERS where ROOM_ID = (select ROOM_ID from CHATROOMS)

the error on this query is logical that the inner query is returning multiple rows on which the outer WHERE is bound Frown | :(

please help me out i am struct in btw my project....

thanks,
tc
regards,
Sana

$@N@

Re: a count query

Wendelius23-Jan-09 10:44

23-Jan-09 10:44

Perhaps be something like:

select c.room_id, count(*)
from chatrooms c
inner join members m
on cm.room_id = c.room_id
group by c.room_id

The need to optimize rises from a bad design.My articles[^]

Re: a count query

sana1723-Jan-09 11:13

sana17

23-Jan-09 11:13

Thanksalot!!!
my problem is solved now..
Allah bless youuu!

tc
regards,
Sana

$@N@

Re: a count query

Wendelius23-Jan-09 11:15

How to modify a DataSet VB.NET

23-Jan-09 11:15

You're welcome Smile | :)

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 8:58

23-Jan-09 8:58

I have populated a dataset with a dataadapter and now I want to change the values. Nothing happens.

All rows are selected

 Dim tblADR_BASE As DataTable
 tblADR_BASE = dsADR_BASE.Tables("ADR_BASE")
 Dim rows() As DataRow = tblADR_BASE.Select()

 Dim intCRNO As Integer



 Dim i As Integer
 For i = 0 To rows.GetUpperBound(0)
     intCRNO = checkForCRNO(rows(i))
     rows(i)("dsp_CRNO") = intCRNO
     rows(i)("CITY_ID") = "test"

Console.WriteLine(rows(i)("dsp_CRNO"))

dsADR_BASE.AcceptChanges()

 Next i

Whats weird is I can wright the supposed changes to the console, but if I actually open the table in the dataset, nothing has been changed.

Am I missing some sort of save?

Thanks

Wendelius23-Jan-09 9:14

23-Jan-09 9:14

With a quick look the code looks fine (although you don't have to call AcceptChanges on every iteration). What does the code look like where you investigate if data is changed.

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 9:24

23-Jan-09 9:24

Thanks Mike,

Dim test = dsADR_BASE.HasChanges

Produces false.

I swear I had this working a week ago on a different table. I have since added fields to this table and think maybe that screwed things up. I have refreshed everything.

Wendelius23-Jan-09 9:29

23-Jan-09 9:29

It's because you call AcceptChanges in the loop. That method clears the modified flag from all rows. The idea behind AcceptChanges is that you let the rows to be modified (or inserted or updated) until you put the data to a safe place (for example database). After that the modification flags can be removed.

So in short, remove the AcceptChanges.

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 9:33

23-Jan-09 9:33

Thanks, I'll give that a try.

But, I added the AcceptChanges after I ran into the issue. But I will sure give it a go.

Thing is, the tables are being restored at the moment, and I have to stay out of it. I'll post results when I can. May be Monday.

Thanks

Wendelius23-Jan-09 9:37

23-Jan-09 9:37

enipla wrote:
But, I added the AcceptChanges after I ran into the issue

If that's the case, check that you don't have acceptChanges (or RejectChanges) anywhere else. When you can you can do the same HasChanges test using debugger after the loop. That way you can confirm that the dataset has been modified by your loop.

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 10:22

Re: How to modify a DataSet VB.NET [modified]

23-Jan-09 10:22

New DB, Same result. I got rid of the only AcceptChanges. There are no RejectChanges.

It still writes to the console

Wendelius23-Jan-09 10:26

23-Jan-09 10:26

After the loop, did you test with the debugger, what's the value of dsADR_BASE.HasChanges

The need to optimize rises from a bad design.My articles[^]

modified on Friday, January 23, 2009 4:38 PM

enipla23-Jan-09 10:39

23-Jan-09 10:39

We are getting somewhere. .HasChanges = true.

When I open the table with the preview data option no data has been changed.

Wendelius23-Jan-09 10:41

23-Jan-09 10:41

If you take a look at the row after you have modified it's values, do you see the change in the data and is the RowState Modified

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 10:47

23-Jan-09 10:47

row.RowState = Modified

And I can print the values out to the console AFTER I leave the loop.

I just don't see the changes when I open the table under the DataSouces Tab.

Thanks again Mike. I'll be leaving work in about a 1/2 hour if I don't get back to you today.

Wendelius23-Jan-09 10:54

23-Jan-09 10:54

Okay. When you have the opportunity, check that you update the data somewhere in you code using SqlDataAdapter.Update and that you don't call Fill before that. That should make the modifications to the original data source.

The need to optimize rises from a bad design.My articles[^]

enipla23-Jan-09 11:06

23-Jan-09 11:06

That did it.

I was sure that I was looking at a DataSet, and that you don't have to update the source to see the changes in the set.

I must not be looking in the correct place. I'm in the DataSources Tab, and it only shows the Tables that I want in the dataset. I assumed I was looking at the DataSet, but I guess that's the DataSource.

Thanks Mike. You did it again for me.

Wendelius23-Jan-09 11:12

Undo and Redo in Databases

23-Jan-09 11:12

No problem at all Smile | :)

The need to optimize rises from a bad design.My articles[^]

rezac423-Jan-09 6:02

rezac4

23-Jan-09 6:02

I wrote a program with vb.net. Its banks are are created in access. Can I add a facility like Undo and Redo to my program?
for example when my user delete some records from my program, then by clicking on a button deleted records add to my banks again.
Or when the user edit some records by clicking on a button the record came back to its prime situation.

Re: Undo and Redo in Databases

Wendelius23-Jan-09 6:56