ADO.NET :: Linq To Entities: Always Select Before Delete And Update?
Sep 21, 2010With linq to entities, how can I delete and update data inside a database without first selecting the complete entity at first?
View 4 RepliesWith linq to entities, how can I delete and update data inside a database without first selecting the complete entity at first?
View 4 RepliesI have a table and i want to use this table in asp.net page
how i will call the stored procedure on the basis
of Stored procedure's Action .
Â
CREATE TABLE Std_Enquiry(
StdID int IDENTITY(1,1) PRIMARY KEY CLUSTERED ,
FirstName varchar(50) ,
LastName varchar(50) ,
[Code].....
I have a GridView and on a row being deleted I trigger the GridView1_RowDeleting sub, but I receive an error "LINQ to Entities does not recognize the method 'System.Web.UI.WebControls.TableCell get_Item(Int32)' method, and this method cannot be translated into a store expression." Code is:
Private Sub GridView1_RowDeleting(sender As Object, e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles GridView1.RowDeleting
' The deletion of the individual row is automatically handled by the GridView.
Dim dbDelete As New pbu_housingEntities
' Remove individual from the bed.
Dim remove_bed = From p In dbDelete.Beds _
Where p.occupant = GridView1.Rows(e.RowIndex).Cells(3).Text _
Where p.room = GridView1.Rows(e.RowIndex).Cells(6).Text _
Where p.building = GridView1.Rows(e.RowIndex).Cells(5).Text _
Order By p.id Descending _
Select p
remove_bed.First.occupant = ""
dbDelete.SaveChanges()
' Increase number of open spaces in room.
Dim update_occupancy = From p In dbDelete.Rooms _
Where p.room1 = GridView1.Rows(e.RowIndex).Cells(6).Text
Where p.building = GridView1.Rows(e.RowIndex).Cells(5).Text _
Select p
update_occupancy.First.current_occupancy = update_occupancy.First.current_occupancy - 1
dbDelete.SaveChanges()
End Sub
The specific line erroring out is: remove_bed.First.occupant = ""
I am trying to update an item with entity framework but I am unable to do that;
[Code]....
it didn't give any error. it passed but when I looked at the database, nothing changed. can you provide me the right way.
I use Linq to Entities and want to update and delete data. I know the ID of the object / record.
How can update and delete without first selecting the complete object (asuming that this is better for performance)?
I am trying to search how to select rows from a datatable. When selecting these rows I should be able to delete the row or edit (update) the row.
I am using the following code to load the data from MsSql 2008 to a dataGridView;
DataTable dtTypes = new DataTable();
SqlConnection con = new SqlConnection(Settings.Default.JLTrackConnectionString);
SqlCommand cmd = new SqlCommand("SelectJobTrackForDate", con); [code]....
Is there any good article which tackles this because I am searching for the bad keywords I think.
I have a student data, when I put the student id in textbox, it show the students mark in gridview like
1st semester marks in first row , 2nd semester marks in second row ,etc
and i want insert 3rd semester marks , 4th semester marks for the particular student , and also , delete , update in gridview....
my EditItemTemplate is not appear in my page, when i load my page it's does'nt exist but I already change my DefaultMode to Edit
View 1 RepliesI have built a web app and want the user to be able to select, update, delete, add data as well as execute stored procedures, I thought that I would get this from the db_datareader and db_datawriter roles but I get an error when trying to select data etcFor instance I get an error when trying to run the stored procedure ups_AddCustomer when the user has the assigned roles db_datareader & db_datawriter but it works fine when the db_dbowner but i would rather not have the page user having full access to the database.
View 1 Repliesi want to know how to call stored procedure in entity framework. how to do code with controller class and with model.
i mean if i want to call insert,update,select,delete stored procedure for entity framework then what are stps i have to follow.
I am using an objectDataSource for the first time. My objectDatasource looks like this:
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" TypeName="CustomerData"
DataObjectTypeName="Customer" DeleteMethod="DeleteCustomer" InsertMethod="InsertCustomer"
SelectMethod="GetCustomersByObject" UpdateMethod="UpdateCustomer" OldValuesParameterFormatString="original_
[code]...
I have a gridview with edit,update and delete options..Using a radiobutton,how it is possible to select a particular row of gridview and update or delete that particular row?
View 3 RepliesI have made a DetailsView which in DetailsView there is action to add the data, change data and delete the data ..how to save, change, delete data, which is in the DetailsView without saving it in the database?so far I use viewstate, but I do not know how to apply it in DetailsView ..
how to create insert , update , delete . in detailsview without saving in database  ..
private void Bindemptydt() {
//Declare a datatable for the gridview
DataTable dt = new DataTable();
//Add Columns to the datatable
dt.Columns.Add("report_id");
dt.Columns.Add("param_field");
dt.Columns.Add("param_label");
[code]....
I have a question about linq delete.
I have 2 table in database and they are joined.
First Table: UserID, UserName, UserSurname, UserPhone, CompanyId
Second Table: CompanyId, CompanyName
First Table I have many recods with related second table.
I want to delete one company in second record, But firtly I have to delete users (more than 1)
How can I delete it with using linq?
I want to know how to Update / delete the table records in ASPNETDB.MDF in single update / delete query ?
View 1 RepliesHow to use Stored Procedures with Linq to Entities? I prefer an example with input and output The videos on asp.net only show how to do this with Linq to SQL.
View 5 RepliesI have a simple join:
SELECT * FROM MessageAlerts AS A LEFT OUTER JOIN Contacts AS C ON A.ContactId = C.Id LEFT OUTER JOIN
Users AS U ON A.UserId = U.Id INNER JOIN Businesses AS B ON B.Id = C.BusinessId OR B.UserId = U.Id
how to do this : ON B.Id = C.BusinessId OR B.UserId = U.Id with linq in entity framework.
WHY are all the examples on this site linq to SQL? Did ms not themselves announce dropping support for l2SQL over a year ago? i really don't get it. Examples are great.. but really not helping me since i've gone ahead and listened to MS. And can someone at MS clarify what the position is for linq 2 SQL.. Is it supported? Recommended? What the hell.
View 7 RepliesI am trying to learn LINQ to entities, and am working out how to best structure my BLL layer. I have generated the entity model and have created a generic repository in my DAL that returns results as IList<T>. I initially created the BLL to also return
results as IList<T>:
public IList<DAL.Customer> SelectAll()
{ [code]...
Now I am working on the aspx page, and I can create an ObjectDataSource and configure it to use my BLL, but since I am returning IList, I can't sort since I am not using a DataView. I have seen some articles on the web for converting IList to DataView, but that seems like a lot of overhead for every query.My goal is to keep a clean separation between layers without making things overly complicated. I would like to know how others have done this, or maybe a link to a good tutorial that shows how to structure all three layers.
I am building a web application in asp.Net 4.0 and entity framework. I am trying to retrieve a list of products based on a collection of id's. I first gather all the id's in a collection and then pass it to the linq query. I am trying to get a functionality similar to the IN clause in SQL. The problem seems to be with the Contains() method in the Linq to entities query. Here is my Linq code:
[Code]....
I got the above Linq to entities method from here: [URL]
I have a message table that self joins to itself where Message.ID == Message.Parent. So I have 1 Message with several ChildMessages. This is set up nicely with a Navigation property.
The code is currently:
var message = from m in soe.Messages.Include("ChildMessages")
where m.ID == id
&& m.IsActive
select m;
return message.FirstOrDefault();
What I really want is to only return 1 Message (that is equal to a particular ID and isActive) with all of its Active ChildMessages and I want to do it in one call to the database.
I have a table of user ids that is huge.
I have an array of user ids that I want.
I have two tables that have a foreign user id key.
What is the best way to get this information performance wise?
Ideally in SQL the final result would be somewhat like this (null values if there is no user ID in one table but not the other):
userid table1value table2value
1 null 12
5 123 null
i have a table with a field name called 'Firstname' and another field name called 'Lastname'. I would want to have a single column in my GridView which show Fullname and then the firstname and lastname are showed here under an alias. Also, i am binding my GridView using LINQ.So is there a way to create aliaswith LINQ and to use these with GridView ? Would love to have an hint about how i can realize this task.
View 5 RepliesI use the Entity Framework and Linq to Entities with MVC 2.0. When use the DropDownListFor from Html helpers to populate a dropdown that contains an ID from a foreign object, I post the form data but I can´t set the correct relation. Using the debug, I can see the ID retrieved from dropdown at my returned foreign object ID, but I think that I not use the association correctly.
View 4 RepliesIn linqtosql you could do something like:
datacontext.CreateDatabase() to generate a database from the model in sql.
I'm wanting to do the same thing in linq to entities.
Say I have a class MyEntities which inherits from ObjectContect is there a similiar method?