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I have a C# windows appliation with an Access database. There are 2 tables: USERS and PERMISSION_TYPES. Table definitions are:
Table Name: USERS
Fields:
First_Name
Last_Name
Address
PERMISSION_TYPE (FK to PERMISSION_TYPES)
Table Name: PERMISSION_TYPES
Fields:
PERMISSTION_TYPE (PK)
DESCRIPTION
The tables are linked vis the PERMISSION_TYPE field. I can make successful updates to the database, however, I'm trying to use a datagrid for each table so the user can Insert, Update, and Delete records in each table.
When the PERMISSION_TYPES.DESCRIPTION field is changed, an error message is returned that states:
"The record cannot be deleted or changed because table 'USERS' includes releated records"
This doesn't make any sense to me, since the DESCRIPTION field is not a Primary Key, and the updates are successful within Access. I have used the generated Update code, and I have written my own update code - I get the same error message.
Does anyone know what is wrong?
Thanks so much,
Randy
dorianr@mail.com
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Hi Randy,
dorianr wrote:
This doesn't make any sense to me, since the DESCRIPTION field is not a Primary Key, and the updates are successful within Access. I have used the generated Update code, and I have written my own update code - I get the same error message.
This sounds really a bit strange - just as the line would first be deleted, and later inserted again
I think PERMISSION_TYPES is just a lookup table. Something that helps
the user of your program to sort the records in the user table. Personally I prefer not to have the user edit a lookup table side by side of the main table.
I do this because:
- the permission type is linked to more than one line, editing with only one row is usually specific, and lookups should be general
- On a multi user system not all users should have adminstrator priviledges, eg access to the options. Defining possible permissiontypes (or more general: options)is the admins task
OK, this does not really solve your problem with the table, but perhaps an other way of doing things might be helpful.
Sascha
--
http://www.livingit.de
http://www.mobile-bookmarks.info
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Hi Sascha,
I'm wondering if there is a problem with the datagrid in .NET 2003 (I have experienced other bugs, but that is anther story). The two tables that I'm discussing are both lookup table that are in the Administration module (not all users have access).
I can solve this problem by adding a numeric, primary key to the PERMISSIONS_TYPE lookup table. I have no idea why using a PK for PERMISSION_TYPE would not let an Administrator update the permission type DESCRIPTION. This solution isn't very feasible, since I'm on the last part of a large project - it would set us back by a lot.
Thanks,
Randy
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that and your violating a relationship issues.
I.E.. see FOREIGN KEY RELATIONSHIPS in dbase theory
I'm not an expert yet, but I play one at work. Yeah and here too.
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I'm not violating FOREIGN KEY RELATIONSHIPS, since I can perform this update directly in the relational database. The problem seems to be with using .NET 2003. I've run tests, and I can perform the same update within the database, just not via .NET
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Yes but the error is stating that and key is bound on that column there fore if you destroy that field then you will have an invalid key assigned to other records.
Access is a crap database and thats why you might have gotten away with it, but SQL does a check on those fields.
Its also possible you might be creating relationships with your code but the problem is key relationships defined either in the database table or the dataset table.
nick
I'm not an expert yet, but I play one at work. Yeah and here too.
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Hiya can someone plz give me the code that lists all the network pcs and their ip addresses in c#.
i have been searching the net now for 2 days and it is very hard to find code that actually works.
Thanks a million.
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I use a multi-threading to implement Socket programming...
when a client have connected to server....
Server initiate a new thread to handle this client-Server's communication...
but the problem is....
I use the thread I made to register a Receice_callBack Function(for asynchronization-communicate),but this thread
stoppd(complete)after doing the register。therefore,the
Receice_callBack can't run correctly(because the thread has stopped....and the error etection happened....
what can i do to make my intantion correctly...???:)
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I'm writing a WebService that outputs a DataSet and need to set a DataRelation for the hierarchical recordset. I've searched and found plenty of parent child table examples, but my table is self referencing by ParentID to RecID. Some ParentIDs are null for top level items. Any ideas?
I already tried cloning the table as below to create the relationship, that bombed...
System.Data.DataTable dtClone = ds.Tables[0].Copy();
dtClone.TableName = "Child";
ds.Tables.Add(dtClone);
string[] strParent = {"RecID"};
string[] strChild = {"ParentID"};
relParChld = new DataRelation("S","Table","Child",strParent,strChild, true);
// Add the relation to the DataSet.
ds.Relations.Add(relParChld);
RecID ParentID
T6975 NULL
T6977 T6975
S34207 T6977
S34209 T6977
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Hi, im looking for an implemantion of some functions, as they are:
Crosscorrelation, Autocorrelation, High-, Low- and Bandpassfilter in C#.
Some help would be nice!
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hi
i ask about6 kan i control windows 98
like disable user from press alt and ctrl and delete
or
from access spicific drive
there is program his name is cybercafepro client
i want to simulate it
the client is controlled by server
i wish that someone can help me
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I was wondering if I made a little app, if I could save the resulting file as an excel file. I searched the articles and found out you can do it through asp .net but I want just a winforms app to do it. What I want to do is either make an app that appends information to an exsisting excel file. Or info on how to make an office addin to take a file and merge it to the currently open file. Any help would be great (heck even some concisive links on information would be nice, not just www.msdn.microsoft.com)
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Well actuall the best tool for this is ExcelWriter by Artisan It does all the encoding and formatting. Of course you can create a plain csv file also but excel writer is awesome for the web and winforms.
This tool is a com and they might have a .net version but I doubt. But it really doesnt matter.
nick
I'm not an expert yet, but I play one at work. Yeah and here too.
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I was looking to make one myself (perferably not asp .net, one to work with winforms) but thanks for the link.
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Well then open an excel file binarily because you have formatting at the beginning.
And really is it worth the development time?
I'm not an expert yet, but I play one at work. Yeah and here too.
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For me yes, it's just a little somthing a friend asked me to do for him so there is no real budget for it.
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You have a number of options available to you :
- use Excel automation. After all, that's what it is for. Of course, this supposes the machine executing your code has Excel installed on it. To know the automation code, just record an Excel macro and translate the resulting VB code into C#. Simple and fast.
- Use ODBC / Excel and create a query that writes to a .xls file
- translate this tiny and fast code[^] into C#. (If you do so, remember to share it on CodeProject).
RSS feed
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I build a C# user control,and use it on a .aspx
because I need a parameter from the request
how can I get the parameter and set it to my control ?
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Hi List:
I have a 2 listboxes (removed item from one, goes to another one) like many 2listBoxes! I hope u get what I mean!
I cant do it correctly! it sis what I've done:
1_ Filled dataset by a DataAdapter!
2_ Made 2 DataViews
3_ Filter DataView1 to flag = 0(false)
4_ Filter DataView2 to flag = 1(true)
but it isnt work properly bc listbox.SelectedIndex is not equal with DataView Row Position!
What should I do to set this?!
Any help appreciated;)
Always,
Hovik.
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Well I'm not an expert but I would say your sorting the listboxes when you should be sorting the dataviews. Never sort the list or combo when databinding, always sort the underlying data source or you answers get FOOBAR'd.
Also if one shows then the other are you creating 2 different views for that?
Just offer suggections no solid answers
I'm not an expert yet, but I play one at work. Yeah and here too.
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Has anyone written a Windows Service that calls a custom DLL. I wrote the service in C# that responds to a timer every 30 minutes (this worked without any problems). Once I try and call my C# DLL which I striped down to the simplest form (it just writes an entry into the event log) it hangs and will not process. I have searched the web and MSDN and have found no answers. Any help would be greatly appreciated.
Mike.
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What I'd do is attach to the service with a debugger and trace thru it.
I gather your C# service is an EXE, and it's connecting to a different C# DLL. Is the EXE built with a reference to the DLL, or are you trying to do something different? Do they exist in the same directory?
One possibility is there is some problem locating the DLL. There's a tool called FUSLOGVW that helps in tracking this sort of thing.
Another thing to check is what account the service is running under. Some accounts, like the XP local and network service accounts have enough privilidge to write to an existing event log source, but not enough to create a new source. Creating of the new source typically happens at installation time.
Hope some of that helps you.
Burt Harris
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Burt, Thanks. I finally got it to work over the weekend. It had to do with the account the service was running under. Acts a lot differently from XP to NT.
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I need a collection to point to individual items in another collection.
How would I write the ionline c++ code inside a c# function
Or can I write a c++ managed code function inside a dll and will it work with my c# application
I'm not an expert yet, but I play one at work. Yeah and here too.
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