Database

12-Oct-04 21:16

EdbertP wrote:
I'm assuming Access won't have such a luxury

What luxury? If you are talking about connection pooling it is done on the .NET side - so it works for Access too.

EdbertP wrote:
I'll try to implement Open before doing a whole bunch of sql operations then.

As I said, this is if performance is absolutely critical. And if that is the case then you should also be looking at structuring everything into as few (a single, if possible) database calls. You will get a bigger performance increase over doing a single open and single close if you do that as there is less communication toing and froing between your application and the database.

Unicode to Big-5 conversion (Any ideas?)

Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.

Re: Connection Object

EdbertP13-Oct-04 17:17

EdbertP

13-Oct-04 17:17

Hmm...the MSDN article that I read only mentioned ".NET Framework Data Provider for SQL Server provides connection pooling automatically for your ADO.NET client application", so I assumed that it's only for SQL Server.

Thanks for the info Smile | :)

Its due when11-Oct-04 20:06

Its due when

11-Oct-04 20:06

Hi Everyone,

Since my last post was so lame I thought id better explain this problem I am encountering. On SQL 6.5 doing a search data conversion from unicode to big-5 was fine no problems there. But after upgrading to SQL 2000 and doing a select in Query Analyzer the data comes up as ??? (which i am assuming is ANSII related somehow) Is there a known issue with SQL2000 doing this? Strange that on 6.5 it works fine and only after upgrading has this problem surfaced. Any help on the matter would be greatly appreciated as this is driving me nuts trying to figure out whats going on. Thanks

excel and oledbexception

its_skar11-Oct-04 15:34

its_skar

11-Oct-04 15:34

hi

I have the following code:

OleDbDataAdapter oleCmd = new OleDbDataAdapter("SELECT [Customer ID], [Customer #], [Company], [Location] FROM [Sheet1$]", oleConn);

DataSet oDS = new DataSet();
oleCmd.Fill(oDS);
The connection string is perfect. no problem with that.

It ran very good until I got this file from the client. though it has the same format and same alignment and same sheet number and etc., myprogram would fail at the FILL dataset line number.
the exception is :
System.oledb.OledbException: No value given for one or more required parameters.

seems to be a bug or something. I really cannot tell.
its erroring out in the thing that in the file they sent the first row is empty.

But, when i delete the first row and execute, program runs fine. again when i do an insert blank row at first, it still runs.
so why it didnt run at first time, and it ran ok second time.?
any format issues with excel ?
( i copied this stuff into a new excel sheet and ran prgm on that and it ran fine on that file)

I just cannot determine what is causing the error and how to resolve it.

can anyone help ?

-messageman

Unforseen problem?

Jerry Hammond11-Oct-04 5:50

Jerry Hammond

11-Oct-04 5:50

Using some code I found on MSDN I have been learning how to connect to a MSAccessDB. The code reads like this:

string DbPath = Server.MapPath("shiplist.mdb");<br />
			string ConnStr;<br />
			ConnStr = "Provider=Microsoft.Jet.OLEDB.4.0;"+<br />
				@"Data Source="+DbPath+";";

Would it not be more elegant to write it as follows:
string ConnStr="Provider=Microsoft.Jet.OLEDB.4.0" + @"Data Source="Server.MapPath("shiplist.mbd")";

Or is there some hidden pitfall that requires that I declare the directory path and DB as a string first as shown in the first example?

Best,
Jerry

I Do Whatever My Rice Krispies Tell Me To.
Toasty0.com

Colin Angus Mackay11-Oct-04 6:05

11-Oct-04 6:05

Toasty0 wrote:
Or is there some hidden pitfall that requires that I declare the directory path and DB as a string first as shown in the first example?

If you declare it in a string first then you can "watch" the value in the debugger more easily, or insert some error checking routing like checking that the file really does exist.

Also, using the + to concatenate strings is really inefficient.

If there was a small number of strings I'd use string.Concat(), or string.Format(). But for a larger number of strings I'd use a StringBuilder.

Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.

Mike Dimmick11-Oct-04 9:59

Mike Dimmick

11-Oct-04 9:59

Ahem[^]. The C# compiler turns multiple '+' operations in the same statement into a single call to string.Concat anyway.

Stability. What an interesting concept. -- Chris Maunder

Colin Angus Mackay11-Oct-04 10:08

11-Oct-04 10:08

I want empirical evidence - He just says it is "zippy"

A collegue of mine did some testing last year to determine which was the fastest between +, Concat and a StringBuilder; the + operator lost the race. So, until I see some contrary numbers I still say that the + operator is slower.

Perhaps what is happening is a+b+c+d gets converted into
string.Concat(a, string.Concat(b, string.Concat(c,d)));

As heard in the film Jerry Maguire: Show me the money!

Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.

Are distributed transactions in MS Access possible ?

Mike Dimmick11-Oct-04 10:31

Mike Dimmick

11-Oct-04 10:31

This program:

public class ConcatTest
{
   public static void Main(string[] args)
   {
      string x = args[0] + args[1] + args[2] + args[3];
   }
}

when compiled csc /t:exe ConcatTest.cs produces the following IL (from Reflector[^]):

.method public hidebysig static void Main(string[] args) cil managed
{
      .entrypoint
      // Code Size: 19 byte(s)
      .maxstack 5
      .locals (
            string text1)
      L_0000: ldarg.0 
      L_0001: ldc.i4.0 
      L_0002: ldelem.ref 
      L_0003: ldarg.0 
      L_0004: ldc.i4.1 
      L_0005: ldelem.ref 
      L_0006: ldarg.0 
      L_0007: ldc.i4.2 
      L_0008: ldelem.ref 
      L_0009: ldarg.0 
      L_000a: ldc.i4.3 
      L_000b: ldelem.ref 
      L_000c: call string string::Concat(string, string, string, string)
      L_0011: stloc.0 
      L_0012: ret 
}

(I was going to post the decompiled C# code but damn me if Reflector doesn't convert it back the other way!)

The four-argument version of Concat can also be examined in Reflector: it calls an internal method FastStringAllocate with the combined lengths of the four strings then makes four calls to the internal method FillStringChecked. If you want to know what's in those, look at the Shared Source CLI[^] - it's supposed to be a slightly cut-down version of the full Framework. Certainly the internal method names are the same!

Now, if you don't know how many strings you want to concatenate, a StringBuilder is probably better (e.g. for building a string in a loop). If you always have a fixed number of strings, Concat may be better. If you're concatenating literal strings, the C# compiler does the concatenation at compile-time.

Stability. What an interesting concept. -- Chris Maunder

Daniel Kailer11-Oct-04 4:13

Daniel Kailer

11-Oct-04 4:13

Hi,

I'm trying to implement distributed transactions with a MS Access database.
Is that possible ? (and if yes, how ?)

greetz

Re: Are distributed transactions in MS Access possible ?

Vasudevan Deepak Kumar13-Oct-04 2:36

Vasudevan Deepak Kumar

13-Oct-04 2:36

Hi greetz:

I think we can check out with this web-based tool for MSACCESS called STP Database Administrator:

http://www.stpworks.com/ [^]

Deepak Kumar Vasudevan
Personal Web: http://vdeepakkumar.netfirms.com/
I Blog At: http://deepak.blogdrive.com/

mysql with asp.net

hazzem elrefai11-Oct-04 1:48

hazzem elrefai

11-Oct-04 1:48

iam going to develop e-commerce website (shopping basket,catalog,.....) with ASP.NET adn Mysql
i didn't use mysql b4, i developed by sql,access,oracle but not mysql.
so plz if any one know there is problems with this compination plz tell me, i know mysql is stable and nice database but all mysql samples was with php languge, and this is why iam afried to use asp.net with it.
thnx in advance

Re: mysql with asp.net

Colin Angus Mackay11-Oct-04 2:33

11-Oct-04 2:33

hazzem elrefai wrote:
b4
plz
thnx

This is not an SMS text message - you have more that 160 characters to play with. The use of these contractions make the text difficult to read.

Okay, I'll answer your question now.

For an e-commerce application I would ensure you use transactions. From the MySql manual: MySQL Server (version 3.23-max and all versions 4.0 and above) supports transactions with the InnoDB and BDB transactional storage engines.

So you need at least the above version plus, it would appear, one of the transactional plugins. (These may or may not be supplied with MySQL, I don't know)

The other thing that I think is important is Stored Procedures. From the MySQL manual: Stored procedures are implemented in MySQL version 5.0. For the benifits of Stored Procedures click here[^]