C# Discussion Boards - CodeProject

9-Aug-09 20:35

I created an offer-report application, C# and MS-Access.
Its multi user application. Not so big, so leave DB part and don't comment Smile | :)

What i want to achieve, is one record viewed by multiple Users.

A record created by a manager(higher marketing person), now he assigns some persons to look after it, and update it. presently he can assign 1 user, and when user log-in with his ID-pass, he can see offer assign to him(Not all).

Now, they want to assign multiple user for single offer.
if one is on leave, another can handle his task.
How to do this?

regards Smile | :)

PIEBALDconsult9-Aug-09 20:42

9-Aug-09 20:42

With a many-to-many relationship; the simplest way is to have a table that contains the IDs of the assignments and agents (or whatever):

Assignment
ID , Description ...
 
Agent
ID , Name ...
 
Offer
AssignmentID , AgentID ... (perhaps datetime of when it was assigned and by whom, etc.)

So then if Assignment 1 is offered to Agents 1 and 2, there will be two rows in Offers -- 1,1 and 1,2 .

Hum Dum9-Aug-09 21:01

9-Aug-09 21:01

I am not getting your idea !!

Doesn't this going to create redundancy in offer table, if for a single offer i create same rows with only change in AgentID?

At present this way i had design DB tables!!

Table - Offer(ID, PartyName, offerDate, etc....., AssignPerson,...)
Table - Users(Name , pass)

table offfer is main table holding all discription about OFFER.
Now at offer creating i simply insert Assign person name in Offer table,
and at login time checks login name and fetch only records

...from offer where AssignPerson = loginName

regards

PIEBALDconsult9-Aug-09 21:19

9-Aug-09 21:19

Hum Dum wrote:
create redundancy in offer table

No, no two records should be the same there.

Hum Dum wrote:
only change in AgentID?

Maybe, but perhaps also in any other fields you may have there, e.g. when assigned and by whom.

Hum Dum wrote:
Table - Users(Name , pass)

Your users should have IDs, then you use the ID, not the name. And are you storing plain text passwords?

Hum Dum9-Aug-09 21:59

9-Aug-09 21:59

PIEBALDconsult wrote:
No, no two records should be the same there.

But all fields are same also data, except AgentID ?

PIEBALDconsult wrote:
And are you storing plain text passwords?
Quote Selected Text

yes. is this incorrect?

Pete O'Hanlon9-Aug-09 22:24

Pete O'Hanlon

9-Aug-09 22:24

Hum Dum wrote:
And are you storing plain text passwords?
Quote Selected Text

yes. is this incorrect?

Yes. Anybody who can gain access to the database can see a users password - remember that this could be somebody who's managed to hack into your system.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

PIEBALDconsult10-Aug-09 5:59

10-Aug-09 5:59

Hum Dum wrote:
But all fields are same also data, except AgentID ?

No, and so what if it is? I suspect you're too new to database work to balk at such concepts.

User ( ID , Name , ... [ password , etc. ] )
1 , Alice , ...
2 , Bob , ...
3 , Carol , ...
4 , Ted , ...

Let's say Alice creates issue 1 and assigns it to Bob, you get:

(I'll use {} to indicate a datetime.)

Issue ( ID , CreatedByID , CreatedWhen , Description , ... )
1 , 1 , {} , "Normalize the database" , ...
2 , 1 , {} , "Document the code" , ...
3 , 1 , {} , "Peer review Ted's code" , ...

Then she assigns them to Bob:

Assignment ( IssueID , AssignedToID , AssignedByID , AssignedWhen , ... )
1 , 2 , 1 , {} , ...
2 , 2 , 1 , {} , ...
3 , 2 , 1 , {} , ...

Later, Carol may assign issues 1 and 2 to Ted:

Assignment ( IssueID , AssignedToID , AssignedByID , AssignedWhen , ... )
1 , 2 , 1 , {} , ...
2 , 2 , 1 , {} , ...
3 , 2 , 1 , {} , ...
1 , 4 , 3 , {} , ...
2 , 4 , 3 , {} , ...

So, you can see that no two rows are the same and can be quite different, especially as time goes on.

You'll need to learn about table JOINs.

Hum Dum wrote:
yes. is this incorrect?

Yes, at least store a hash of the password instead of the actual password:
0) When someone sets a password, store the hash. (I use SHA-1[^])
1) When someone logs in; take the provided password, hash it, and compare the new hash to the stored hash.

Hum Dum11-Aug-09 20:35

11-Aug-09 20:35

thanks for your needful reply.

cheers Smile | :)

PIEBALDconsult12-Aug-09 4:09

12-Aug-09 4:09

Glad to be of service.

Comboboxes in DataGrid

AmbitiousBeginner9-Aug-09 20:31

AmbitiousBeginner

9-Aug-09 20:31

hi;

i wonder if there's a designer support for inserting ComboBoxes into a DataGrid in windows applications, rather than writing codes for it since the samples are too complicated. can anyone help?

--- Thanks

PIEBALDconsult9-Aug-09 20:46

9-Aug-09 20:46

0) Why are you using a DataGrid(View) ?
1) Are you trying to allow editing in one?

See this[^] recent thread.

AmbitiousBeginner9-Aug-09 20:52

AmbitiousBeginner

9-Aug-09 20:52

yes, i need to present an sql table in a grid and allow the user to change its values if needed. one column of the grid should have restricted values, so i thought it might be a good idea to insert a combo for it and i found several samples which were too complicated and time-consuming. if there's other ways of restricting values for a DataGridColumn, i'll be glad to learn.

--- Thanks

PIEBALDconsult9-Aug-09 21:23

9-Aug-09 21:23

AmbitiousBeginner wrote:
i need to present an sql table in a grid

Who says? That's a very poor way of presenting information to a user.

stancrm9-Aug-09 20:48

stancrm

9-Aug-09 20:48

???

Just add a column using designer and set the type to ComboBox.

AmbitiousBeginner9-Aug-09 21:18

AmbitiousBeginner

9-Aug-09 21:18

there's no such thing! you can either add a boolColumnStyle or textBoxColumnStyle when creating a table style for your grid. where can we change a column style to ComboBox???

--- Thanks

How to update MS Access database in the installed application?

stancrm9-Aug-09 21:22

stancrm

9-Aug-09 21:22

Which version if VS do you use ?
I think, you are able to set column style to DataGridViewComboBox since VS2005.

Sifar - 09-Aug-09 17:38

Sifar - 0

9-Aug-09 17:38

Hi,

I have a setup program that installs my application with an MS Access database. Now, when I have to provide an update to a client, I again build a setup program and give them this setup.

The client unistalls his existing program and installs new setup. This process also wipes out his existing database. To overcome this, I set permanent property of database in the setup TRUE. This has resolved the above problem.

But now... I have updated few tables in my database. The clients must be provided with the update such that his existing data must be retained intact...

HOW to achieve this? Any suggesstion will be greatly helpful?

Regards,
-SIFAR.

Re: How to update MS Access database in the installed application?

Ennis Ray Lynch, Jr.9-Aug-09 18:27

Ennis Ray Lynch, Jr.

9-Aug-09 18:27

My standard practice is to write migration scripts for new versions of the database. Then you can use the migration scripts to update the old database. This can be a lot of code to maintain so what you do is an iterative update process. IE, convert DB V1 to DB V2 then convert the newly created DB V2 to DB V3, etc. This is much easier than writing infinite migration scripts. Be cautious because you will come across database that just cannot be upgraded with 100% accuracy if you do not have a solid change control policy in place.

Need custom software developed? I do custom programming based primarily on MS tools with an emphasis on C# development and consulting.

A man said to the universe:
"Sir I exist!"
"However," replied the universe,
"The fact has not created in me
A sense of obligation."
--Stephen Crane

Regular Expressions [modified]

Mikey_H9-Aug-09 17:29

Mikey_H

9-Aug-09 17:29

I am learning how to read text files at the moment, and it seems regular expressions is the way to go for what I need. I understand the concept but not quite sure how to implement it.

I have the line...

$2 USD NL Texas Hold'em - Sunday, August 09, 19:05:42 EDT 2009

...stored in a string. I would like to take certain parts of this and store them in seperate strings.
The data I need is...

NL Texas Hold'em
August 09
19:05:42
2009

Should I use something like "USD\s.*\s-" this would give me "USD NL Texas Hold'Em -"? After this I can then trim "USD " and " -" off the start and the end of the string and I will the information I need.

Regex rExp = new Regex("USD\\s.*\\s-");
Match match = rExp.Match(sLine1);

string gameType = match.Value;
gameType.TrimStart("USD ".ToCharArray());
gameType.TrimEnd(" -".ToCharArray());

switch (gameType)
{
      case "NL Texas Hold'em":
      // Do something
            break;
      default:
            break;
}

Is this a good way to approach the task? Are there better ways to do this?
Any help would be appreciated.

Thank you.

modified on Monday, August 10, 2009 1:18 AM

Re: Regular Expressions

PIEBALDconsult9-Aug-09 21:33

9-Aug-09 21:33

Ah, thanks, I was just working on a Regex tester; you gave me something to test! Big Grin | :-D

With that input, this Regex:

\$\d* \w* (?'Game'.*?) -.*?, (?'Date'.*?), (?'Time'\d\d:\d\d:\d\d) \w* (?'Year'\d*)

Produces:

Match: $2 USD NL Texas Hold'em - Sunday, August 09, 19:05:42 EDT 2009
    Group 0: $2 USD NL Texas Hold'em - Sunday, August 09, 19:05:42 EDT 2009
    Group Game: NL Texas Hold'em
    Group Date: August 09
    Group Time: 19:05:42
    Group Year: 2009

(You should also look into Expresso.)

Re: Regular Expressions

Mikey_H10-Aug-09 9:30

Mikey_H

10-Aug-09 9:30

Thanks Piebald, thats the sort of expression I was looking for. Far more simpl than what I had originally.

// Parse line 2 to find game type, date, and time of hand
Regex regExp        = new Regex("$\\d* USD (?'GameType'.*?) -.*?, (?'DateMonth'\\w*?) (?'DateDay'\\d*?), (?'DateTime'\\d{2}:\\d{2}:\\d{2}?) \\w* (?'DateYear' \\d*?)");
Match line2Match    = regExp.Match(sLine2);

switch (line2Match.Groups["GameType"].Value)
{
     case "NL Texas Hold'em":
         // Do something         
         break;
     default:
         break;
}

Re: Regular Expressions

PIEBALDconsult10-Aug-09 9:53