IDE :: Creating A Foreign Key Removes The Relationship
Mar 25, 2009
I think this is an IDE problem, but may be my lack of understanding, so apologies if I am wrong.I have an SQL database, VS2005 app working fine, but if I put a foreign key constraint on the relation between 2 tables, as soon as I try to access the table it throws an exception as shown below. Exception.InnerException for details. The error is: DataMember property 'tblProduct_tblStock' cannot be found on the DataSource.If I delete the foreign key constraint it works perfectly happily. I am at a loss since the error seems to be one that I would expect at compile rather than run, and anyway does not seem to be true since the relationship is clearly there in the DataSource (otherwise I wouldn't be able to edit it to remove the constraint!) Possibly I am doing something stupid, but the exception is confusing me too much to let me see it. All I am trying to do is ensure that I can't create a stock record without the product existing, without coding a check - which I thought was a straightforward SQL approach
I'm using a dataset class written by others who have defined the foreign key relationships between tables using the tools in the schema diagram. I'm binding the dataclass to a windows form. I'm running into an issue where I have an existing header record and I'm trying to insert data into a child table via a grid programmatically. The child table contains all keys for data. As the grid is bound to a binding source, I'm simply adding rows directly to the grid programmatically.
When I attempt to save the data, I get the error ForeignKeyConstraint FX_Activity_UserRoleActivity Requires Child Key Values (4) to exist in the parent table. The value (4) is one of the foreign key values and it does exist in the parent table. The error occurs when I tell the bindingsource associated to the child table on the form to EndEdit. Looking at the XSD file for the dataset, both foreign keys are set up for 'Both Foreign and Key Constraint' with Cascade set for both update rule and delete rule. Accept/Reject rule is set to none.
Running a SQL trace, I confirmed that SQL Server is not generating the error, so it is occurring on the client application somewhere. First what does the error actually mean? Second, does the configuration of the foreign key relationship in the dataset's XSD file have anything to do with it? If so how should the foreign keys be set up between the tables? If it isn't how would you go about troubleshooting this issue as stepping through the code ends with the .EndEdit call to the binding source.
Im would like to create relationships between my tables from different database. im using VB 2008 and SQL 2008 as my database. Is the relationships should be made on my database itself or tru coding in my VB? If either which how can i do that.
Basically, I am trying to write a LINQ to Objects statement where the relationship is a grandparent, parent, child relationship. (You could also call it a Master Detail relationship.)
Dim coverages As New List(Of Coverage) Dim coverage As Coverage For Each rl In oClaimsPolicy.RiskLocations
<HttpPost()> Function Edit(<Bind(Prefix:="Article")> ByVal Article As FormCollection, Optional ByVal DepartementID As Integer = 0, Optional ByVal LeverancierID As Integer = 0) As ActionResult ', ByVal ReferenceSupplierID As Integer ' Dim Art As Article = ArticleService.GetArticleById(Article.ArticleID) Dim _toUpdateArt As Article = ArticleService.GetArticleById(Article(0)) UpdateModel(_toUpdateArt, Article)
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toUpdateArt.Departement = Nothing and _toUpdateArt.Supplier = Nothing is to remove the optional relationship.But it only works when i debug it and sometimes after several loops of the command, before the relation is actually removed and it's stored in the database.When there isn't a breakpoint on the "function", the Relationship will never be nulled.Does anyone has an explanation for this and how to fix this?
I have a system icon (for example a folder icon) and I want to display it in a richtextbox. That's not a problem, but the transparency of the icon is gone and is replaced by a blue color. I tried to use the MakeTranparent function of the bitmap object, but with no luck. How can I make the bitmap transparent again?
Here is my code:
Dim _mycurrentFolder As String = "C:Test" Dim _folderIcon As Icon = GetSystemIcon(_mycurrentFolder) Dim _folderBitmap As Bitmap = _folderIcon.ToBitmap()
I have created a winform which is having a DataGridView control, based on some condition i am coloring few cells in red color.
' Array MismatchRecords is containing rows and column no. of each cell needs to be colored For y = 0 To UBound(MismatchRecords) Dim Row = CInt(Split(MismatchRecords(y), "|")(0))
I have a process which grabs the birthdate and from a data table and display them in a masked text box for viewing and editing However when pushing the data into the textbox any preceding zeros get removed For example 05/05/2005 would display as 55/20/05__
The masked Text box is set up as 00/00/0000 The line which assigns the code is:
I am creating an HTML document using HTML agility pack. I load a template file then append content to it. All of this works, but when I view the output file it has removed the closing tag from my <br/> tags to look like this <br>. What is causing this?
Dim doc As New HtmlDocument() doc.Load(Server.MapPath("Template.htm")) Dim title As HtmlNode = doc.DocumentNode.SelectSingleNode("//title")
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I ended up just reading in my template file as a standard string then loading the html like this
Dim TemplateHTML As String = File.ReadAllText(Server.MapPath("Template.htm")) TemplateHTML = TemplateHTML.Insert(TemplateHTML.IndexOf("<div id=""topContent"">") + "<div id=""topContent"">".Length, _ html.ToString) doc.LoadHtml(TemplateHTML)
I've made a small program that creates a registry item in the users run key (basically starts the program on bootup), my question is does anybody know how to remove the item from all the users of the computer when the program is uninstalled?.
I know that all the other users registry hives aren't loaded at anyone time and feel a custom action dll that runs on uninstall that iterates through the 'documents and settings' folder loading the hives one at a time and removes the registry key.
I am able to browse to a file and save its path in a textbox, but the slashes from path are removed when saved to the database. C:Program FilesApplicationDocStudio.bmp becomes C:Program FilesApplicationDocStudio.bmp Public Class FormSettings Dim Result As String [Code] .....
I have a listbox were users can add items to. Then i also have a remove button which removes the selected item. The listbox also has a datasource, so to remove an item i uses this
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But i also want sorting on the listbox. But when i clicks the remove button, it removes random items, not the selected one. How can i fix this?
I remember we were taught BASIC (Beginner's All Purpose Symbolic Instruction Code) language in school, when we were in 5th grade. It was purely in DOS-Mode and we basically used it for drawing. Then I learnt Visual Basic 6.0 quite a few years basic. I neve found a similarity between them
I have two tables which need to be connected using a one-to-one relationship. In SQL Server 2005, how would I add this relationship to the database diagram, do I just leave the relationship blank? Is there any pre requisite queries I have to add? How do I connect these tables in VB? .. the same way I would connect a one-to-many?I need the Student table to be linked to the Class Table where One student can be in only 1 class.
I have an asp:table which I want to exported to excel. One of my fields are alpha numeric and when exported to excel the leading 0s are stripped off. After going through this thread: Validation (CSS 2.0): 'mso-number-format' is not a known CSS property name I would like to use the css method "mso-number-format:@;.But the css is not exported to excel. I just tried to test it with simpler css things like bold font etc but its not getting carried over. I can see that if I surround my asp:Label with tags this change gets carried over to the excel but not the css bold . Other solutions in other thread does not work for me as ="00111" shows up as desired in excel but in the web form it shows up as ="00111" which is not what i want.
My issue involves relationships and cascaded effects between properties, and I'm wondering what best practices are on this.I have a class that contains a list of varying length of numbers. When editing the list, sometimes the user prefer to set a TargetSum, so that the program enforces the list will always add to this sum. I am accomplishing this by programmatically setting the final element in the list such that list sum = TargetSum. For example, if the user chooses to UseTargetSum, then sets TargetSum = 10, then creates a list of length 4, and enters 1, 4, 2 for the first 3 elements, then the final element is programmatically fixed to 3. The user cannot change the final element themselves.
I do this behind the scenes by handling all necessary events, such as a list element value change, list length change, and the UseTargetSum option change. For each event trigger, it recalculates the last element's value.It works but then there was a bug when loading saved data. If a list is loaded by sequentially adding the elements, the handlers modify each entry. Regarding the example, when the first value of 1 is entered, the handlers say "a value was just added, the sum should be 10, there is currently only one element, so it needs to be 10". So the first element gets changed to 10 behind the scenes. When the second element is next added, the handlers say "a value of 4 was just added, but the first element is already 10, so it should be zero." At the end of the load, the final list reads 10,0,0,0 instead of 1,4,2,3.
I know it is possible to rearrange the load procedure such that I get the correct list. For instance, I could avoid enabling the TargetSum event handlers until after all the data is loaded. The list would first be created as 1,4,2,3 and then the handlers would change nothing.
But this experience makes me wonder if I am opening the door for other sneaky side effects. It seems you should be able to load data without worrying too much about an implicit ordering. It also seems unusual to have "cascading" effects between class properties. Is there a more accepted approach?
The other alternative I'm considering is to only enforce TargetSum only inside UI forms. Ie, when you know it's a user making the change, then enforce the TargetSum, but otherwise leave the core class logic alone.That way database loads, etc, are left unaffected. But I guess the downside of not having ubiquitous enforcement is that opens the door of incorrect sums via some unforeseen complication.
I have made a small "front-end" application for an Access databasefile.
I set up 3 tables with relations in Access, and added the database as a datasource in my project. I have done no database programming, and the app has worked nicely for about 2 years. It's a simple master-detail form with 2 datagridviews dragged from the datasource window.
Yesterday I opened the project to add a new form. The form is just a "setttings form" with no database activities.
When I press F5 - the main form do not start, and I get the error message "DataMember property '{0}' cannot be found on the DataSource." - where the property name is the name of one of the 2 relationships in the datasource.
If I a many-to-many relationship between Users and Roles and I have an instance of a User entity and several Role Ids can I insert a relationship between the two types of entities without having any other Role data and without doing a select on the Roles first? Update:
I might not have been clear enough. I don't have an instance of a Role, only the role id. Is it possible to create the relationship between User and Role without filling a Role object from the database first?
I am trying to input value to AppSchedNumber into my AppInfo table which is the primary key of my AppExamSchedule (auto inrement). The problem is I can't insert on my AppInfo because my AppSchedNumber on my AppExamSchedule should be the same.
I am using VS2008 Standard, Access 2007 and VB.net. I have an Access db with a Membership table, a DuesPayment table and a table linking the two together.
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1) In VS I have a single form (frmMembership). I used the Data Sources window to create a single datasource containing the tables tblMembers, tblDuesPayment and lktblMemToPay. from the 'Data Sources' window I drug tblMembers, as text boxes, to the form. I drug tblDuesPayment to the form as a DataGridView.
I right-clicked 'dsMembership...Edit in Dataset Designer' and checked that the relations between the three tables was as shown above. I left all other settings as they were created by VS.When I execute the app I get the member information as expected and can use the TblMembersBindingNavigator to step through the members. The DataGridView, instead of showing dues payment information for the member showing on the form, shows ALL of the dues information for ALL members does not exhibit any relationship between tblMembers and tblDuesPayment.
2)I also tried creating a dataset for tblMembers only. Then I used 'dsMembership.Edit in DatasetDesigner' window to create a TableAdapter for tblDuesPayment and lktblMemToPay. I got the same results.
3) I tried various other combinations, like creating TableAdaptors for tblMembers and a TableAdaptor for a combination of lktblMemToPay & tblDuesPayment.
how F# is a language which allows you to approach problems in a different way than in C#/VB.NET, i.e. instead of "pushing bits around" you "chain together data transformations", and that how F# will "become like XML", something that you use in addition to your language of choice (C# or VB.NET) in order to solve certain problems in a more efficient way.This got me to thinking about the relationship of the .NET languages, here's how I understand them:C# and VB.NET are syntactically but not substantially different, i.e. a C# programmer would not learn VB.NET in order to "approach problems in a new way"however, a C# or VB.NET programmer would learn F# in order to "approach programming problems in a functional way"but what about IronPython and IronRuby? Chris mentioned that "F# learned a lot from Ruby and Python" so I would think that F# has a similar relationship to IronRuby/IronPython and C# has to VB.NET. However, a little googling around tells me that IronRuby and IronPython are both built on the DLR but F# is not.
How are the relationships between F#, IronRuby and IronPython to be best understood?
