Re: Dataset.Merge problem - Database Discussion Boards

ppp00116-Jun-05 19:05

16-Jun-05 19:05

Hi,

I am struggling in using dataset or traditional dataReader in ADO.Net.
It seems to me that if I use the dataset (direct bind it to UI), then the dataset will replace the object model layer, so it seems only good for simple application development without much object model logic.
If I insert a object layer
above the dataset, then it seems no difference from the traditional
approach by using DataReader with SQL query. Then what is the goodness
of dataset ?
And if I use dataset, the cached data by read/write in the dataset will be lost if the application hang, so the cached data by read/write should be restricted within the scope of one transaction.

Are all my perceptions on using dataset above right ? Any comments?

Thanks

My Program uses Microsoft Access

Sasuko16-Jun-05 8:29

Sasuko

16-Jun-05 8:29

I've create a software that uses microsoft access 2003, better it manage with ado.net a .mdb database.
To distribuite that application have to have got the final user Microsoft Access to get working the applicationo or it is not need?

Re: My Program uses Microsoft Access

Hesham Amin18-Jun-05 4:02

Hesham Amin

18-Jun-05 4:02

No the clients only need JET driver on their machines (can be obtained freely from microsoft).

Installing SQL CE on PPC2003

Rossi4616-Jun-05 3:55

Rossi46

16-Jun-05 3:55

Hi
I'm having trouble installing SQL CE. It is installed, and i can see the sql query analyzer icon, once i run that. The normal SQL CE screen comes up, but there's no tools options at the bottom. Have I installed in wrong or is it something else.

Thanks

Rossi46 -> The Doctor Laugh | :laugh:

Now i have my database connected

deeboy16-Jun-05 3:49

deeboy

16-Jun-05 3:49

Now that i have my database connected and my acces page doing what it needs to do...I am ready to introduce the world to my database...But how do i get the User Interface to be up all the time without building it over and over...i just want to pull it up type the entry in and update my database...but for now i can only do it on the computer i made it on...You see i am ready to put it on the computer for everyday use.......

Dataset.Merge problem

Eduard Keilholz16-Jun-05 3:12

Eduard Keilholz

16-Jun-05 3:12

Hey there,

I have two datasets with exactly the same tables and exactly the same columns. I want to merge the second dataset into the first dataset, but i want to maintain the original row version of the first dataset.

ds1.Merge(ds2, true, MissingSchemaAction.Ignore) only changes the Original Row version of ds1's rows and ds1.Merge(ds2, false, MissingSchemaAction.Ignore) changes both Original AND current value... is there no way to change only the Current version of a row??

I cannot ds2.Merge(ds1) because i have a modified dataset class which inherits datasets but also maintain a connection to a database. ds1 and ds2 are both connected to diffrent databases and changing the connection after merge doesn't work ;-(

Re: Dataset.Merge problem

Eduard Keilholz16-Jun-05 4:05

Eduard Keilholz

16-Jun-05 4:05

thinking one step beyond solves the problem, which means I've already got a solution...
for this interested, you need two merges...

ds2.merge(ds1, true, MissingSchemaAction.Ignore)
ds1.merge(ds2, false, MissingSchemaAction.Ignore)

Re: Dataset.Merge problem

LockonFlamingCliffs16-Jun-05 4:11

LockonFlamingCliffs

16-Jun-05 4:11

Hi!

I have written my own datatable merge function. It merges 2 datables, adding ew clumns to the source if those dont exists, and also append the new rows to the source. Hope my code is of help to you?

Michiel Erasmus
MaxCredible B.V.

Nieuwezijds Voorburgwal 44
1012 SB Amsterdam

Postbus 11079
1001 GB Amsterdam
Postbus 11079
1001 GB Amsterdam

T: +31(0)20-3449070
F: +31(0)20-3449071
I: http://www.maxcredible.com

<br />
#region MergeDataTables(), merge 2 datatables.<br />
/// <summary><br />
/// DOEL:	Merge 2 datatables.<br />
/// AUTEUR:	Michiel Erasmus<br />
/// DATUM:	©30-maart-2005 Maxcredible B.V.<br />
/// </summary><br />
/// <param name="dtInput"></param><br />
/// <param name="dtOutput"></param><br />
/// <param name="eersteRijIsSomtaal"></param><br />
/// <returns></returns><br />
<br />
public DataTable MergeDataTables(DataTable dtInput, DataTable dtOutput)<br />
{<br />
	return MergeDataTables(dtInput, dtOutput, false);<br />
}<br />
<br />
public DataTable MergeDataTables(DataTable dtInput, DataTable dtOutput, bool addNewRowsToMerged)<br />
{<br />
	if(dtInput == null)<br />
	{<br />
		return dtOutput;<br />
	}<br />
<br />
	try<br />
	{<br />
		if(dtOutput == null)<br />
		{<br />
			dtOutput = dtInput.Clone(); //kopieer de structuur van de bron, straks kopieer allse van bron naar dtOutput.<br />
<br />
			if(dtOutput == null)	// het is onmogelijk die bron datatable te kopieren.<br />
			{<br />
				return dtOutput;<br />
			}<br />
		}<br />
<br />
		try<br />
		{<br />
			foreach(DataColumn dc in dtInput.Columns)<br />
			{<br />
				if(dtOutput.Columns[dc.ColumnName] == null)<br />
				{<br />
					dtOutput.Columns.Add(dc.ColumnName, dc.DataType);<br />
				}<br />
			}<br />
		}<br />
		catch<br />
		{<br />
			string strTijdelijk;<br />
			strTijdelijk = "dummy";<br />
		}<br />
<br />
		//kopieer de data<br />
		foreach(DataRow drInput in dtInput.Rows)<br />
		{<br />
			DataRow drOutput;<br />
<br />
			if(dtOutput.Rows.Count == 0 || addNewRowsToMerged)<br />
			{<br />
				drOutput = dtOutput.NewRow(); // kopieer een rij uit de datatable.<br />
			}<br />
			else<br />
			{<br />
				drOutput = dtOutput.Rows[0];<br />
			}<br />
<br />
			drOutput.BeginEdit();<br />
<br />
			foreach(DataColumn dcInput in dtInput.Columns)<br />
			{<br />
				try  // kopieer de kolom, als die in de mergetable is, anders gewoon doorgaan.<br />
				{<br />
					drOutput[dcInput.ColumnName] = drInput[dcInput.ColumnName]; // kopieer per kolom<br />
				}<br />
				catch<br />
				{<br />
					string strTijdelijk;<br />
					strTijdelijk = "dummy";<br />
				}<br />
			}<br />
<br />
			drOutput.EndEdit();<br />
			if(dtOutput.Rows.Count == 0 || addNewRowsToMerged)<br />
			{<br />
				dtOutput.Rows.Add(drOutput);<br />
			}<br />
			dtOutput.AcceptChanges();<br />
		}<br />
		dtOutput.AcceptChanges();<br />
	}<br />
	catch(Exception ex)<br />
	{<br />
		throw new Exception(ex.Message + "; Stacktrace=" + ex.StackTrace, ex);<br />
	}<br />
<br />
	return dtOutput;<br />
}<br />
#endregion<br />

met vriendelijke groet,
Michiel Erasmus

Re: Dataset.Merge problem

Eduard Keilholz21-Jun-05 22:43

Eduard Keilholz

21-Jun-05 22:43

Ziet er op zich wel OK uit, maar denk dat het niet een oplossing was geweest voor mijn probleem. Ik heb een selectie van data die ik uit de database trek, op een laptop zet en zonder database connectie wijzig. Daana wil ik een sync doen van de data terug naar de db. Ik heb dan twee identieke datasets (qua structuur dan) alleen is de 'sql' dataset gevuld met oude data, en de 'nieuwe' dataset gevuld met de up-to-date data. Ik moet in de 'sql' dataset dan wel de gewijzigde rijden bijhouden (nieuwe, gewijzigde en verwijderde) om aan een adapter door te geven wat hij in mijn db moet wijzigen... moeilijk verhaal allemaal (waarschijnlijk omdat ik het onhandig uitleg) maar vooral door de AcceptChanges kan ik de wijzigingen niet meer terugvinden en ben ik dus alsnog de row states kwijt.. echter, de oplossing was al gevonden middels een dubbele merge..

Trouble with a Access Db w/password......

Qwick Miller15-Jun-05 15:52

Qwick Miller

15-Jun-05 15:52

When I set a password to my access db.

myCon = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=db.mdb;Password=password");

myCon->Open();

I get a exception error.

"The workgroup information file is missing or opened exclusively by another user"

..but when I remove it, it open ok. What other param's I need to set in order to open a password protected access db?

Re: Trouble with a Access Db w/password......

jonathan1516-Jun-05 0:51

jonathan15

16-Jun-05 0:51

if its the database password and not tied to specific users then try the following connection string
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " & sFullPath & ";Mode=ReadWrite;Persist Security Info=False; Jet OLEDB:Database Password=" & sPassword

Where sFullPath is the full path and filename of the db and sPassword is the db password.

Jon

Filling a DataTable from a SearchResultCollection

Teddy Biesecker15-Jun-05 10:02

Teddy Biesecker

15-Jun-05 10:02

Guys/Gals,

I've not been able to find a "neat", reliable way to fill a DataTable with the results of a DirectorySearcher. I tried multiple variations of the available DataAdapters that I could find, but none seemed to be "adaptable"... (I made a funny!) Laugh | :laugh:

Anyway, I'm trying to stay away from a direct LDAP call to AD, and use the DirectorySearcher/SearchResults. I wouldn't think that it would be too difficult. I'm sure there's some way that the Framework will let me do this.

Your assistance is greatly appreciated...

-Ted

Please help me

Stanciu Vlad15-Jun-05 9:16

Stanciu Vlad

15-Jun-05 9:16

I am in need of a third party tool for a database import/export.
I need to do these operations from a database (say mysql) to an other one (say ms sql). Can anybody suggest me an other option except MS Enterprise Manager from SQl Serv 2000? It would grately help if that application is a free one (gpl).
Thank you.

I hope you understand...
By the way... visit http://nehe.gamedev.net[^]

Re: Please help me

Christian Graus15-Jun-05 16:18

Christian Graus

15-Jun-05 16:18

Enterprise Manager won't talk to MySql.

Christian Graus - Microsoft MVP - C++

Re: Please help me

Stanciu Vlad15-Jun-05 18:15

Stanciu Vlad

15-Jun-05 18:15

Actualy I managed to make "it talk to mysql" through ODBC adapters.
So my question remains. Can anybody help me?
All I need is a application that can read all the data from a database in a specific server and write it to an other server (like from MS sql 2000 to mysql)

I hope you understand...
By the way... visit http://nehe.gamedev.net[^]

Batch command execution?

Judah Gabriel Himango15-Jun-05 4:42

Judah Gabriel Himango

15-Jun-05 4:42

Hi guys,

I've got a smart client application that allows the user to change, create, or delete data that's stored in an MSDE SQL database. I've rolled my own messaging queue so that the when a client updates lots of data at a time (e.g. deletes 500 rows of data, create 2 rows, update 100 rows), I send a batch message to my server application containing 602 sub-messages describing what happened (in other words, one big message containing all the actual messages describing what happened). This way I only have to go over the network from client to server only 1 time.

All that works great.

My problem is that now that the "delete 500, create 2, update 100" batch message is on the server, I have to call a stored procedure in the database for each message: call RemoveRow stored proc 500 times, call CreateRow 2 times, call UpdateRow 100 times.

Using the ANTS .NET profiler to look at my code, it is apparent that this execution of several hundred stored proc calls is a bottleneck. Is there any way to allow the MSDE database to execute a batch of commands all at once? Or better yet, is there a better way of doing this?

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Conversation With a Muslim
Judah Himango

Multiple tables for same category in database?

kbalias15-Jun-05 2:39

kbalias

15-Jun-05 2:39

Hi all

A database question.

Say for example I have a Suppliers table and a Products table in my database. If theoretically each supplier can supply millions of products what would be the most efficient and convenient?

Having a different Products table for each supplier, or a single Products table holding products of all suppliers. If the first option is better would it not be very tricky querying the data for reports and so on?

Thanks again.

Kobus

Re: Multiple tables for same category in database?

Colin Angus Mackay15-Jun-05 2:53

Colin Angus Mackay

15-Jun-05 2:53

kbalias wrote:
what would be the most efficient and convenient?

That depends on how you are going to use the data. You can split the data by supplier and have a partitioned view to stich it back as if it were one big table - you can then query through the view.

Personally, I would keep it as one supplier table and one products table unless you run into performance problems then do work on eliminating the performance issues. I find that second guessing SQL Server on performance is often counter productive because the usage patterns are often not what was originally envisaged.

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Sql Query Required!

Zishan Haider15-Jun-05 2:28

Zishan Haider

15-Jun-05 2:28

I have a column with type datetime in an employee's table. I want to delete the records that older than 3 working days. The problem is I can't use getdate()-3 in where clause because I don't know about the holidays and all.. Can anyone help me out ?

Regards,
Zishan

Re: Sql Query Required!

Colin Angus Mackay15-Jun-05 2:41

Colin Angus Mackay

15-Jun-05 2:41

Zishan Haider wrote:
The problem is I can't use getdate()-3 in where clause because I don't know about the holidays and all.. Can anyone help me out ?

You will need information on the holidays if you are to achieve this.

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Re: Sql Query Required!

Zishan Haider15-Jun-05 2:46

Zishan Haider

15-Jun-05 2:46

Can't I use some kind of loop in the SQL Confused | :confused:

Re: Sql Query Required!

Colin Angus Mackay15-Jun-05 2:49

Colin Angus Mackay

15-Jun-05 2:49

You can use loops in SQL but they are very inefficient. However, you've already said that you don't know the holiday information so I don't see how a loop is going to be useful.

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Re: Sql Query Required!

Colin Angus Mackay15-Jun-05 3:01

Colin Angus Mackay

15-Jun-05 3:01

Assuming you have a table called Holidays with the a column containing the date of each holiday you could write a query like this:

DECLARE @days int;
SELECT @days = COUNT(*)+3 FROM Holidays
WHERE HolidayDate <= getdate() AND HolidayDate >= getdate()-3

You can then use the @days variable to count back the number of days. For example:

DELETE FROM MyTable WHERE somedate < getdate-@days

Does this help?

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Re: Sql Query Required!

Zishan Haider15-Jun-05 21:36

Zishan Haider

15-Jun-05 21:36

Well.. you're right couldn't do it in SQL without a holidays table. However I did it in my C# program. I selected distinct dates from table ordered by Date Desc. Then I deleted every record with the date from my select query ignoring the first three.. Blush | :O

Yes I know its poor performance, but this chunk has to run once every morning so I don't need any major performance here. And I had to do it without A holidays table. Thanks for your help Smile | :)

Regards
Zishan

Questions OleDB JET4

Saksida Bojan14-Jun-05 23:07

Saksida Bojan

14-Jun-05 23:07

1. How to look witch tables are in the database.
2. Is possible to create database with my application. And How?

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