Does anyone no of any good resources regarding many-to-many relationships? More specifically on displaying data from many-to-many tables in ASP. Struggling to find anything but I may just be over complicating things!
View 18 Repliesi did like all instruction in this link
[URL]
but i have a problem,this erer arise "Can not find tabel1"
So I am working on an MVC project to put to work the studying I have been doing. I am wrestling with the concept of Database Table relationships and foreign keys. I am working on a simple ecommerce site (displays products, shopping cart, user accounts..etc).
I have the following tables to start out with:
1) Products
2) Categories
I setup the Products and Categories tables to have a ProductId and CategoryId respectively. In my MySQL db, I created a FK on the Products Table to relate to the CategoryId field on the Categories table (I am not sure this was correct to begin).
My expectations for the way the database would handle the table relationship: I didn't want the DB to do anything with the products table if I deleted a category out of the Categories table, or vise versa. The only thing would be that the category field in a Product would be blank (or default) if their category was removed.
Finally, do I have to do anything in my entity classes such as in the Products class, add the ProductId to the Category.ProductId?
Eventually, when I Orders and Users to the project, I can see a relationship where each user -> many orders -> each order has many products -> and each product is in one category.
But I am having a hard time understanding how or if I should be setting up a Foreign key relationship in the two current tables of Products and Categories and if so how to setup my entity class in relation to that FK.
I have been experimenting with WebMatrix, specifically the ability to connect to and use SQL CE data.
My question is:
When I am creating a new SQL Compact database with several tables, how do I define relationships between the tables?
The "Relationships" button in WebMatrix is always greyed out. Is that because it is still in Beta? Or am I missing something?
I'm a newbie to this so bear with me. From what I've read online LINQ to Entity should see the relationships without having to specify the joins between multiple tables. I have a relationship that goes across 4 tables Employee, EmployeeDepartmentLink, EmployeeProjectLink, and Project. The idea is an employee can be in multiple departments and work on multiple projects with it being specified which department the employee is in for that project.
This is a C# MVC3 program connecting to a SQL database using VS 2010 Express.
I have no problem with running this query to find employees on a project:
[Code]....
Tring to do the reverse, finding projects that an employee worked on results in an error:
[Code]....
Error message: The specified type member 'EmployeeDepartmentLinks' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. So I have 2 questions,
1) Why would it work in one direction and not the other? I've played around with it for a couple days with the same results.
2) Does it matter that my primary key and foreign keys are not named the same since all the relationships are connected in SQL? Ex: in Employee (EmployeePK)--(EmployeeFK) in EmployeeDepartmentLink Trying different stuff in LINQPad I was able to get the 2nd query to work if I specified all the joins which I thought was not neccesary with LINQ to Entity. I converted an SQL query that I made on the server into a LINQ query below which works.
I have a table that contains item data. If the item is a particular type further information exists to describe the item. The additional information isn't that heavy however the number of records in relation to the main file will be quite small (less than
5%).
So I have 2 scenarios:1) Put the additional data in the main table and take tha hit on storage
2) Create an additional table and link the 2 together
If we were talking huge amounts of data I can understand that 2) would be the obvious choice but given the simplicity should 1) be a consideration?
If 2) is the answer - is it possible to create a dependency between the 2 tables when the item is 'that' particular type. In other words wnsure the addition data is populated for the required items and not others.
I want to display details STRONGLY TYPE In a view this would be done as normal through the list, hiting the details link. however a table of notes is connected to the main table of info. i want to us the id of the main table item to list all the notes that have been entered about the record in the main table. how do i do this
View 1 Replieshere I can find some info on how to display data from my MSSQL database in something like old style tables (table,<tr>,<td>) becouse I used to done it like this in classic asp but i had a formula for calculating where to put tr or td and it becomed very confused, not to mention displaying gruped records like 10 on each page...I tried gridview in VisualStudio but I can not find any info how to use sql in it so I think it can not help me becouse it is to much predefined and I do not know where I can change code for it like what data source to use, sql and other important thing
View 3 RepliesI want to display data from one record in a ListView control. There are two other tables that could contain associated records. For each table, if there is an associated record, I want to display the data from a particular field. I'm only concerned with the item amd alternate templates
View 3 Repliesone: table of employees (empID,empName,Isemployeed)second; table of dates: Date Third: table of status of each emp at a particular date(empID,date,status)
View 6 RepliesI want to display another merged table on the same datalist showing another merged table so that any of the displayed merged table that recieves data first will show on top of the datalist.This is the first merged table showing on datalist
SET QUOTED_IDENTIFIER ON
GO
ALTER PROC [dbo].[GetMessage]
@UserName VARCHAR(200)
AS
BEGIN
SELECT
[code]...
've gone through the nerddinner.com tutorial and got excited when I saw that they were actually using two tables (dinner, rsvp) in the linq to sql model that they were building. Unfortunately for me, they never put them both on the same page together and I'm a bit lost trying to get this to work. For simplicity sake let's call this application a forum with two tables for now
View 5 RepliesI have created an ASP web program on one server, when I move over to another server, all of the tables turn into lists, which is causing some problems. Below is my code on the original server
HTML Code:
class="right-col" /></div>
<span id="FFBFPrimaryLabel" class="left-col">Does your organization consider xxx?*</span>
<table id="RadioFFBFPrimary" class="right-col-radio" border="0">
<tr>
<td><input id="RadioFFBFPrimary_0" type="radio" name="RadioFFBFPrimary" value="Yes" /><label for="RadioFFBFPrimary_0">Yes</label></td>
[code]...
Basically I need to know how to prevent my code from changing my tables to lists, as you can see has happened above when i copied directory over to new server.
Using dataloadoptions i have tried the following example
[Code]....
Now i need to ask how can i display Category ID and Category Name of the productID (i am supposing that One product can be in at most one category) by extending the above example Regards.
I am using bulk insert concept to export the data from dat file to tables(Two tables). I am using the temporary table for to do the calculation and insertion to two tables. My problem is whenever I selecting the temp table data after the execution of bulk insertion , the order is changing .I need to get the order as it is in file order(csv,dat,txt).
View 5 RepliesWhat is the best approach to one to many relationships?
This is my scenario:
I have a simple one to many relation:
Customer
CustomerID
Name
tel
CustomerNotes
Id
Note
customerID
I want to have a DETAIL view of customers and CREATE view for CustomerNotes all in the same page.
I create CustomerController and the different views and its respective actions for edit, create, delete, etc.
I also create a CustomerNotesController and the views and actions like before, but I made the views PARTIALS
I put a RENDERPARTIAL for the CustomerNotes create view in the Details view from Customer.
When I run the app, the page is render as expected: It shows the detail info of the customer and bellow the create form for the notes. However, when I click SAVE, nothing happens. I put a breakpoint in the notes controller and never get hit.
I also try with RenderAction and don't work at all.
I'm having a hard time wrapping my head around how to use the Memberships in MVC. I know there is the built in ASPNETDB database which has all the basic tables for users and such. But what if I wanted to add a relationship between one of my custom tables and this built in user table?
If I had a database table that contained blog comments, we'll call it Comment. And each Comment had a userID associated with it could I do something like?
User.Comments.Add(someCommentObj)
how to create C# classes to represent one to many relationships in C#. I have a Customer and an Address table in my database. I also have a Customer class in my C# solution but how do I introduce the multiple address element? Do I have a separate Address class? Do I create a subclass in the Customer class or create a method in Customer called GetAddresses of type List which contains all of the relevant logic? In my code I need to be able to return a customer with all associated addresses and I just cannot picture the best way to achieve this using OOP.
View 9 RepliesEF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this:
Entry entry = ModelContext.GetObjectByKey(new EntityKey("ModelContainer.EntrySet", "Id", id)) as Entry;
entry.ChildEnteries.Load();
if (entry != null)
{
ModelContext.DeleteObject(entry);
ModelContext.SaveChanges();
}
I get errors related to the relationships: A relationship is being added or deleted from an AssociationSet 'EntryEntry'. With cardinality constraints, a corresponding 'Entry1' must also be added or deleted. Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 1 I've tried few variations and all of them throw exceptions.
this is a bit of a nomenclature question:what is the correct way to describe the relationships between these classes (the thing that throws me off is the use of generic types here):
[Code]....
Say I have this entity with a lot of attributes. In the input form I have decided to implement a wizard control so I can collect information about this entity in several steps. The problem is that I need to collect information that has been modeled has many to many relationships. I am planning to use a telerik gridview to manage this (add/edit/delete), the problem is where do I store that data since the entity in a insert form is not created on the database yet. OK so I can store all that info in temporary lists residing in the viewstate, waiting for the final submit where I dump all that in the DB, but one of the steps I am collecting files...now storing files in the viewstate is out of the question, same as as storing them in the session...I have been thinking of implementing in a way that the user has to submit some info first (say first 3 steps), commit the data to the database creating the parent entity and then start inserting all the childs entities...but this will get weird as it's confusing since on the first steps you not saving the data to the DB and on the next ones you are commiting directly...
View 1 RepliesJust a quick question for those more familiar with FluentNHibernate. I've read the quick start things, and the docs on their site, but am still a tad off. Are the following maps correct, in terms of the HasOne / HasMany relationships? If not, correct them, and give me reasons, so I better understand.
C sharp Code:
[code]....
These will eventually go into a convention file, but for now, I just need to know how to code relationships period.
I'm using SQL Server 2005 in a project, and i need to duplicate a record from a table and all it's relationships.
View 9 RepliesI have the following related tables:
Users
Id
Username
Email
Password
UserStatuses
Id
Name
Users_UserStatus
Id
User (FK - Users: Id)
Status (FK - UserStatuses: Id)
StatusDate
As you can see, UserStatuses is a reference table with various statuses. Users_UserStatus is a join table between Users and UserStatuses. Using Entity Framework, how can I do a conditional to check if the latest StatusDate is "Pending"? As of now, I have the following:
[Code]....
Does anyone know of a control or a way to render a group of object relationships like visio? Right now I just have them sitting inside nested divs, but it's not as slick as everything being connected with lines in a flow
View 1 Replies