Re: multiple updates - C# Discussion Boards

23-Jul-02 19:48

Hi Guys,
I have a method that does multiple updates(hundreds of them) into SQL server.The data is in the form of array of objects . Now i'm looping through them and updating them one at a time .This is taking much time .Is there an efficient way of doing this?

Thanks in advance Smile | :)

sarith sutha

SimonS23-Jul-02 23:00

23-Jul-02 23:00

Sarith,
can you give me an example of one object in your array?
Maybe a code snippet.

Cheers,
Simon

"Sign up for a chance to be among the first to experience the wrath of the gods.", Microsoft's home page (24/06/2002)

Sarith Sutha24-Jul-02 3:14

24-Jul-02 3:14

i hope this will do

for(int index = 0 ; index < TaskItems.Length ; index++)
{
piSqlStmt=new StringBuilder("INSERT INTO Tasks (Task_id,Task_Desc,Task_status) VALUES";
piSqlStmt.Append("'"+TaskItems[index].Task_id+"'");
piSqlStmt.Append(",'"+TaskItems[index].Task_Desc+"'");
piSqlStmt.Append(",'"+TaskItems[index].Task_status+"'");
piSqlCommand.CommandText = piSqlStmt.ToString();
piSqlCommand.ExecuteNonQuery();
}

sarith sutha

jparsons24-Jul-02 4:12

24-Jul-02 4:12

Instead of manually doing it this way, you could use the DataSet classes and create a table locally. Then add the entire table to your Database.

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Sarith Sutha24-Jul-02 18:50

24-Jul-02 18:50

Thanks a lot jparsons,
I think this is much better way. Big Grin | :-D

sarith sutha

David Stone24-Jul-02 12:39

David Stone

24-Jul-02 12:39

Why are you using the for{} statement? For accessing an array of objects, you should use the foreach{} statement...

David Stone
dstone@newcenturytitle.com

Procrastination is like masturbation; it's all good until you realize you just screwed yourself.
-Writing on a bench at college

SimonS24-Jul-02 21:37

24-Jul-02 21:37

David Stone wrote:
Why are you using the for{} statement? For accessing an array of objects, you should use the foreach{} statement...
I don't really see the benefit of this.

Unless using an index on the array object causes a lookup each time, similar to using field indexes in a recordset.
Is this the case here too?

Cheers,
Simon

"Sign up for a chance to be among the first to experience the wrath of the gods.", Microsoft's home page (24/06/2002)

leppie24-Jul-02 23:03

leppie

24-Jul-02 23:03

David Stone wrote:
Why are you using the for{} statement? For accessing an array of objects, you should use the foreach{} statement...

You can only use the foreach statement if the array (collection) does not get modified in any way. IOW If you have to alter a property during the foreach loop, you will get an exception and you have to revert to the for statement.

As far as I can see , the foreach statement is purely a shortcut for

IEnumerator en = Array.GetEnumerator();
do 
{
	Object obj = en.Current;
} while (en.MoveNext());

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

SimonS24-Jul-02 21:33

24-Jul-02 21:33

The idea of creating a new dataset with this data and then adding it as a whole to the database might work (as per post).

Another idea would be to package all the data into parameters (i.e. have a parameter each for: ID, Desc, Status and add all ID's to the ID parameter and all Desc's to the Desc parameter etc...) You can then split these up using T-SQL. I have some script for this if you'd like.

You're probably going to have to weigh up the performance as well as whether or not the "tasks" table can be recreated each time.

HTH

Cheers,
Simon

"Sign up for a chance to be among the first to experience the wrath of the gods.", Microsoft's home page (24/06/2002)

Sarith Sutha24-Jul-02 22:19

24-Jul-02 22:19

Hi Simon,
I would Like to have the script.
Thanks in advance . Smile | :)

sarith sutha

SimonS24-Jul-02 23:09

Using current user credentials with Task Scheduler Library

24-Jul-02 23:09

Here's the debug version of my script.
There are a number of assumptions that I took, viz: delimiter value and length and I didn't need to do any escaping of characters in "array".
If you have issues implementing this, feel free to contact me: simon_stewart@hotmail.com

DECLARE @Array varchar(50)
DECLARE @iStart int
DECLARE @iEleFound int
DECLARE @iMaxEleLen int
DECLARE @iNextDelimIndex int
DECLARE @iEleLen int

SET @Array = '1,2,3,4,5,6,7,8,9,65,66,67,100,101,102,654321'
SET @iStart = 0
SET @iEleFound = 0
SET @iMaxEleLen = 5
SET @iNextDelimIndex=0
SET @iEleLen =0

print '---------'
print 'LENGTH of string: ' + CAST(LEN(@Array) AS VARCHAR)
while CHARINDEX ( ',' , @Array,@iStart ) > 0 -- for each element in the array
begin
SET @iEleLen =1 --default
--if not ',' or ''
if (CAST(SUBSTRING(@Array, @iStart + 1, 1) AS char(1)) <> ',') and not(len (SUBSTRING (@Array, @iStart + 1, 1)) = 0)
begin--element found at this index

SET @iNextDelimIndex = CHARINDEX ( ',' , @Array,@iStart+1)
if(@iNextDelimIndex=0)
begin
SET @iNextDelimIndex = CAST (LEN(@Array) AS VARCHAR)+1
print 'latest element is next:'
end
SET @iEleLen = @iNextDelimIndex - @iStart
--DB function would occur here
print 'NEXT DELIM LOCATION-->' + CAST(@iNextDelimIndex AS VARCHAR(10))
print 'VALUE FOUND-->' + RTRIM( CAST(SUBSTRING(@Array, @iStart + 1, @iNextDelimIndex - @iStart-1) AS char(10)) ) + '<--'

SET @iEleFound = @iEleFound + 1

end

else --no element found at this index
begin
print 'do nothing'
end

SET @iStart = @iStart + @iEleLen

end --if (CAST(SUBSTRING(@Array, @iStart + 1, 1) AS char(1)) <> ',') and not(len (SUBSTRING (@Array, @iStart + 1, 1)) = 0)

print '------ ELEMENTS FOUND: ' + CAST(@iEleFound AS CHAR(2)) + ' ---------'

Cheers,
Simon

"Sign up for a chance to be among the first to experience the wrath of the gods.", Microsoft's home page (24/06/2002)

Keith Mai23-Jul-02 13:17

Keith Mai

23-Jul-02 13:17

Hi There,

I'm using David Hall library and is running into a bit of problem. When creating a task, we can supply the user and password in which the task shall run. The problem I am having is that I want to schedule a task to run with all the priviledges of the current authenticated user, in other words, the person running the program should be the person executing the task when the time comes. I am trying to avoid saving the password of the user and sending it to the task scheduler. Are there anyway I can tell the system to grab my credentials and use that to run the scheduled tasks?

Thanks,

netmodules

jparsons23-Jul-02 10:37

23-Jul-02 10:37

I've recently been playing with command line compiles of my C# projects. Beeing accustom to C and C++ I'm used to building all of my files into object code and then compiling all of hte object code together in the end. Looking around I thought that "csc /t:module" was the answer.

However i was very mistaken. Everything will compile with /t:module just fine and it willa ll apparently compile together at the end by using the /addmodule switch. However the resulting executable is still dependent upon the .netmodule files.

Is there any way to combine the .netmodule files into one assmebly so that it is no longer dependent upon all of these small little object files. My main intent here is to create incremental builds so that I'm not recompiling all of my classes at the same time. Any advice would be appreciated.

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Eric Gunnerson (msft)24-Jul-02 5:33

Eric Gunnerson (msft)

24-Jul-02 5:33

You can use alink (al.exe) to create an assembly from the modules.

I will warn you, however, that netmodules aren't supported in the IDE and aren't widely used.

csc already supports incremental compilation with the /incremental switch, which should meet your needs. If that's not fast enough - or you don't want to use it - I suggest you break your projects into multiple assemblies.

jparsons24-Jul-02 5:50

24-Jul-02 5:50

Eric Gunnerson (msft) wrote:
csc already supports incremental compilation with the /incremental switch, which should meet your needs. If that's not fast enough - or you don't want to use it - I suggest you break your projects into multiple assemblies.

This was actually what I was looking for. I don't know how I missed it in the documentation. Thanks.

Eric Gunnerson (msft) wrote:
You can use alink (al.exe) to create an assembly from the modules.

However doesn't this still maek the final .exe dependent upon the .netmodules?

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Eric Gunnerson (msft)24-Jul-02 9:53

Eric Gunnerson (msft)

24-Jul-02 9:53

jparsons wrote:
Eric Gunnerson (msft) wrote:
You can use alink (al.exe) to create an assembly from the modules.

However doesn't this still maek the final .exe dependent upon the .netmodules?

I don't think so. The only real dependencies in .NET are at the assembly level, and alink just grabs all the IL and metadata and creates an assembly from it.

jparsons25-Jul-02 3:01

25-Jul-02 3:01

Maybe I'm not being clear when I say dependent. What I mean by dependend is if Assembly A is dependent on netmodule B then B must be in the same directory as A to execute. Quick Example.

Test.cs

using System;
public class Test {
  public void SayTest() { Console.WriteLine("Test"); }
}

Hello.cs

using System;
public class Hello { 
  public static void Main(String[] args) {
    new Test().SayTest();
  }
}

Now if I compile with the following lines.

$>csc /t:module Test.cs
$>csc /t:module /addmodule:Test.netmodule Hello.cs
$>al /main:Hello.Main /t:exe /out:Hello.exe Test.netmodule Hello.netmodule
$>Hello
Test

This works as expected. However if I delete the netmodules and try to run Hello again the microsoft debugger comes up. What I want is a way to add the modules completely so that their "netmodule" state is no longer needed.

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n