.net - ASP.NET MVC - Have A Foreign Key As The Primary Key?
Oct 5, 2011
Is it possible to have a Foreign Key as the Primary Key?
<Key()>
Public Property AssignmentID() As Integer
<ForeignKey("AssignmentID")>
Public Overridable Property Assignment As Assignment
Public Overridable Property User As User
For the code above I get an error:One or more validation errors were detected during model generation:System.Data.Edm.EdmAssociationEnd: : Multiplicity is not valid in Role 'AssignmentLocks_Assignment_Source' in relationship 'AssignmentLocks_Assignment'. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be �1�.
I'm trying to create a table which has one (or none) record per assignment.
I'm having some major issues trying to figure out What's going wrong with my code.
The general problem is that I can't get the foreign key in one of my child tables to populate the primary key from the parent table. I have a parent table named "ISSUES" and a child table named "ISSDESC". The primary key for ISSUES is ISS_ID which is an autonumber. The foreign key is ISS_ID in the ISSDESC table which is just a number. I'm using MS Access and an OLEDBConnection as the method. I've created the relationship in MS Access and also created the datarelation in the VB.NET code.
I am able to submit the information into the database into the two tables but the foreign key isn't being populated therefore not being linked to the other table.
I think it's probably a very simple fix, but it's been eluding me for a good 8 hours or so. I am using a dataset and 2 data adapters, one for each table.
I just watched a video from Beth Messi about setting up a primary key and foreign key on a table.
I created two tables, one called customer and the other one called orders CustomerID is the primary key to the customer table OrderID is the primary ket to the orders table and CustomerID is foreign key to the orders table
Beth Messi said that this would maintain the integrity of the tables and she also mentioned something about setting up a cascade delete so that when we delete a record in the customer table, the customer's order in order table will get deleted as well.
how I can set up the cascade delete, Meanwhile, I tried deleting a customer record in customer table - a customer with orders, and I got the following error when I clicked save.
The DELETE statement conflicted with the REFERENCE constraint "FK_Orders_Customer". The conflict occurred in database "C:DOCUMENTS AND SETTINGSLOUISLOCAL SETTINGSAPPLICATION DATATEMPORARY PROJECTSWBINDEBUGTEST.MDF", table "dbo.Orders", column 'CustomerID'. The statement has been terminated.
Shall I use try catch to warn the user that the record that I tried to delete has an order? They can't delete the customer unless the orders table's record is deleted first?
How do I fetch the loginID and display the student data on the textbox?E.g. I login with loginID of 18 but it only display the data of 12
Private Sub frmLibrary_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 'TODO: This line of code loads data into the 'LibraryDataSet.Student' table. You can move, or remove it, as needed. Me.StudentTableAdapter.Fill(Me.LibraryDataSet.Student) End Sub
I am using a number of tables on my application and two of which have a foreign key constraint I have set between them. When I change the account number on the main table via a combo box all of the relevant information for that table on the form is updated accordingly. However, the child table which has a foreign key reference to the Account Number of the main table is not updated when the acocunt number is changed. I have set the update to cascade in the references but still am having issues.
This is a follow-up to a previous question regarding locking on two List(Of T) objects. Suppose I have a function like this:
[code]...
which resides in a class that declares List1. In a multithreaded environment, I now understand that I should have a private locking object for List1 and lock List1 whenever it's modified or enumerated. My question is, should I do this:
On a client i have an anonymous list containing a multi-column primary key previously selected from the DB.Then i need to select all the records from the DB that equals the primary key list i have stored in the memory.[code]
The general problem is that I can't get the foreign key in one of my child tables to populate the primary key from the parent table. I have a parent table named "ISSUES" and a child table named "ISSDESC". The primary key for ISSUES is ISS_ID which is an autonumber. The foreign key is ISS_ID in the ISSDESC table which is just a number. I'm using MS Access and an OLEDBConnection as the method. I've created the relationship in MS Access and also created the datarelation in the VB.NET code.
I have a pretty standard MySQL-query in my winform application like this:SELECT * FROM tblTable WHERE tblTable.tableID = " & variable..One of the fields is a foreign key. And when I try to add a record to my datagridview I get the error:Cannot add or update a child row: a foreign key constraint fails..Can't MySQLCommandBuilder make INSERT-commands with tables containing foreign keys?
I have a parent table called users which stores all the user info with a prime key field called ID. Now in the child table which has a seperate foreign key associated with the ID field in the parent table.
What I would like to do is be able to populate the foreign key once once the user uploads data into the child table with the user ID it has.
So far I have created the associated foreign key with ID field in the user table and also programmly through data-relation related the table but now sure on how to get the value from the relation.
The foreign key in the child table is called 'U_ID' as shown in the snipet velow.
I'm developing an app in VB.Net (Visual Studio Express 2008, on Windows Vista) that connects to an Access relational database. The database has 3 related tables (TextSections, LineItems, Cycles) that I'm loading into my dataset. I've set up two foreign key constraints and want all changes to cascade through the related records in the child tables. I cannot get the cascades to reflect through.
For example, when I delete the parent record, the children records remain (in the database - they are removed from the dataset). Also, when I modify the parent record (change the Description field for example), the change is not reflected in the dataset datatable that holds the children records - unless I go through and ReLoad all of the data from the database and re-Set the constraints. I have set the .AcceptChanges, .UpdateRule, and .DeleteRule to cascade, and have also set EnforceConstraints on the dataset. Why aren't the changes cascading through the children?
Below I've pasted (1) the Load Routines for my datatables TextSections (parent), LineItems (child), and Cycles (child of LineItems); (2) the method that creates the constraints in the dataset, and (3) The Save routine for TextSections.
Friend Sub LoadTSTable() Dim key(1) As DataColumn Dim newCol As New DataColumn
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.
about some APIs I can get the hwnd of a foreign application. But is there a possibility to detect if this application has areas with scrollbars (for example internet explorer hast a menu, tabbar and an area with scrollbars)? If so, how can I get the rect of this area and how can I access this area (scrolling-event).
I am displaying a table with a Report Viewer control. The table contains a foreign key to a child table, and I want to display the value from the child table for the particular foreign key.How do I do that? Using VB in vs2010.(Eg.The parent table contains a field called BrokerID, which is a key to the Brokers table.I want to display the value of BrokerName from the Brokers table associated with the BrokerID from in my Report).
Is there a simple way that I can replace a foreign key in a datatable, with a corresponding value from the table that the key is referring to, without having to create a new table or use tableadapter? Ive got a table that has a foreign key to a child table, and I need to get a column from that table to fill a dataview?
I have an application where I need to be able to search for the workers related to a company from a contacts list. I am able to do this by entering the company number but I am unsure how I can set the query to allow to search for the information in the other table.
[Code]...
SELECT RecordNo, CompanyID, AccntRep, CustNumber, Person, SubjectID, StatusID FROM dbo.Contact WHERE CompanyID = @companyNo I think that I need to create a join in the SQL statement to the company table but am unsure how to go about this and I would be grateful if someone would give me a point in the right direction so that i can search for the company name instead of the companyID.
I'm trying to use a DataTable to get the schema of a SQL Server DB.But, when try to detect the ForeignKeys, the constraints collection only brings the UNIQUE constraints.
Private Sub ShowConstraints(ByVal tableName As String) Dim table As DataTable = New DataTable(tableName) Using connection As SqlConnection = New SqlConnection(GetConnectionString)
I have some text in an .rtf file which uses a non-English character-set (it's chinese).When I open this in Wordpad or Word I see just the chinese characters.When my app opens the .rtf file and reads the file's contents and puts it into a RichTextBox for display, I get "everything" from the .rtf file, i.e.:
I am trying to allow the user to enter data in any foreign language, (Cyrillic, Arabic,etc.) by entering the data into a textbox.Unfortunatly when I change the language of the test machine it still fills in the US standard ASCII characters instead.
On my first form, I have a combobox that is bound to the Locations table and displays all the different locations. Once a location is selected, a 2nd form is loaded which has textboxes which are also bound to the Locations table and are populated with the corresponding data.
Here's my issue: on the 2nd form, I have combobox that is bound to the Offices table. Currently, when this form loads all the available offices, displaying with the first office in the list. I need it to populate with the correct office based on the selection made on the combobox on the first form. I guess what I'm asking is, how does one bind a combobox to a foreign key b/c it is the foreign key, office_refnbr, from the Locations table that needs to display in the Office combobox.
I've tried a variety of bindings, including:[code...]
How to insert multiple data into mssql without using loop?i'm developing a clinic management system, while doctor may give few medicines to patient,therefore i hope inside my database,the data will look like [code]
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 am not particular with the database approach of Foreign Key a manner wherein a data related to another data. Table1 > Relations > Table2 How to make a foreign key and how to use that in coding ?
I have a header table and a related details table with a one-to-many relationship from master to details.I understand that I will have problems saving details if the master data isn't already there, and I've been working around this. (VS 2008, SQL Express 2008, app is running on XP)
I've been getting around this by checking if there's any detail data on the save click event and warning the user that they need to save the master first before adding details.So the user then removes the detail, clicks save, and then adds the details and clicks save again. Although not good, that's been working OK, but now I need to make the details mandatory. So at the moment they can add a new record, save it and no details.What I would really like to do is to save everything at once. I saw a related post that said I needed to use a transaction, Is that the best approach? Or is there a way to save the master first then the related details all when the save button is pressed?
I have a Database with the following tables, PolicyHolder, Beneficiary, FinacialDetails, Gender, Nationality, Relationship, Income. They are all linked by ClientID primary key of the PolicyHolder table.
When i'm adding my data in the Beneficiary table using a DataGridView i get an error when im adding the second entry saying - FK ClientID already has a value and this value cannot be duplicated. I want the FK ClientID value to be saved on every record i enter under Beneficiary.
Want to know how to create a exception handler if say you have a form that has a foregin key in it, how does one put an exception handler to prevent the operation of this producing a VB.NET Error when i want to delete a record?