I am trying to update a table using LinQ. Though records are getting inserted, for some reason they are not getting updated.what can be possible problem
Dim db as new empDataContext
Dim emptable as new employee
if update then[code].....
If this is a stupid question, then let me know. I can't just figure it out.First of all, this is my question. How do I detect the changed value on those text boxes?I have an idea that I create a another string values that have the original values and compare them right before saving or form closing event. This sample just have 3 text boxes, but I have 50 + text boxes on my one form. I can do it that way, but that is not really smart idea.Can I use abcDB.SubmitChanges() to detect any data changes on text boxes?
Dim sqlQuery = (From obj in abcDB.HelloWorld
Select obj.Fname, obj.Lname, obj.PhoneNumber).FirstOrDefault()
me.textboxFname.text = sqlQuery.Fname
[code].....
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I have the following records in the table student(see in fig 1). I am trying to update the Name of student whose Roll no =1. But Record is not updated in the database,
[Code]...
The table is not getting updated.
I'm trying to access 2 tables within the same DB in Access 2007, but I have a problem when saving information to one of the tables, I can do it with one table but when I try to save the information to the second table the data gets overwritten, not sure why, because I use the same procedure for both of them, just changing the variables to avoid mixed data, this is the code that I use to connect with the DB and fill the DataSet:
Try
dbProvider = "PROVIDER=Microsoft.ACE.OLEDB.12.0;"
dbSource = "Data Source=.\Almacen.accdb;Jet OleDB:Database Password=Slackware"
[code].....
Again, it works fine when saving info to one table, but using the exact same procedure (with different variables) saves the new data but overwrites the previous information
I am getting an incorrect repsonse after an update to a table. In my RowUpdating event I have the following code which builds an Update Parameter to call an SP to update a table. I must be doing something wrong but everything runs fine. My rowsAffected variable reports 1 after the update, but the table never gets the data.[code]I found a solution that is working. On the original DataSource for the update command I needed to add the following.[code]This in essence allows the original data source to call the SP. Note: that the command type needs to stay as TEXT not Stored Procedure as one might think.
View 3 Repliessince I still use VB6 and the code is in VB8, I can't find the solution.The sub below is executed in a button's click event, and is supposed to save data to his database. It seems to work fine : you can add persons (in a separate form), and see them appear in the datagrid. You can stop the program, go back to the VB editor, and run it again (without rebuild), and the previously added persons will still be visible in the datagrid. But...If you add some persons, then go to the editor and force a rebuild (for example by adding more code), and than run the code again, the the previously added persons are gone (nomore visible in datagrid)!To me, it seems that the problem is to effectively update the database. I have searched on the internet about this topic, and I read that you must "set" the UpdateCommand.
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I want to update a date field in my table when a record is updated to reflect when the last update was made. I have this for the parameter: objEXTCommand.Parameters.AddWithValue("@entryDate", Now.Date)
However, this inserts the Date and a time of "12:00:00". I want the date and current system time. I've gone about several ways, but none seem to work. I try this: [Code]
I have two tables Employees and CafeLogs. Some employees can be cashiers and also customers at the Cafe shop.
Table structures:
Employees: EmployeeId(PK) , FirstName, LastName
CafeLogs: LogId (PK), CashierId, EmployeeId, Value, => CashierId and EmployeeId are the data from column EmployeeId of Empoyee table
Table relationship:
Employees 1:N CafeLogs (CashierId (FK))
[code]....
Right now I know how to select only LogId, Employee's name, and , Value, not with Cashier name yet.
Dim query = From log In db.CafeLogs _
Join emp In db.Employees On emp.EmployeeId Equals log.EmployeeId _
Select log.LogId, emp.FirsName, emp.LastName, log.Value
part of my code is in below
[Code]...
I would expect to see the path.Path include the new record, however, I also notice that tempnextgen also include the new record. Can anyone help me out on this issue? Why the tempnextgen got updated as well, how to prevent this unexpected operation?
I have 2 Tables Table "A" and Table "B". Here is little details.
Table "A"
---------
ItemID (Primery Key)
ItemSKU
[Code]....
I have two tables:
table1
case_no flow result
tc_1 001 pass
tc_1 002 pass
tc_1 003 pass
tc_2 001 pass
tc_2 002 fail
tc_2 003 pass
table2"
case_no result
tc_1 pass
tc_2 fail
Table2 should be updates from table based on the results... If all results is PASS then the table2 should be updated as pass... if any result is FAIL then the entire case_no should be updates a s fail..
I would like to know the best, or standard, way to accomplish real-time client updates in a small multi-user application using an access data table as a data source.Specifically, this application will be used by 3-4 people. It uses a datatable which is filled on form load and bound to a datagrid at design time. The datatable is stored on a shared drive. The data table on the shared drive is updated in two ways:
1) Users can update the datagrid which then updates the datatable on the shared drive via the data adapter's Update method.
2) A server application does some work on some text files, periodically updating the data table.
I need the clients to reflect the changes to the data table on the shared drive as closely to real-time as possible. I know that the data table stored in memory on the client is disconnected from the data table on the shared drive, so I must query again to get the updates.
1) Is there an alternvative model I can use which is connected, and which will automatically reflect the updates in the data table on the shared drive?
2) If not, what is the best way to check for changes in the data table (so I can know when to call the data adapter fill method)? I am planning to poll the drive for a change to the .mdb file, raise an event and then fill the data adapter when the event is triggered. I am using this method successfully now to check for changes to a text file in another application, and I know how to implement it?
I would like to know the best, or standard, way to accomplish real-time client updates in a small multi-user application using an access data table as a data source.
Specifically, this application will be used by 3-4 people. It uses a datatable which is filled on form load and bound to a datagrid at design time. The datatable is stored on a shared drive. The data table on the shared drive is updated in two ways:
1) Users can update the datagrid which then updates the datatable on the shared drive via the data adapter's Update method.
2) A server application does some work on some text files, periodically updating the data table.
I need the clients to reflect the changes to the data table on the shared drive as closely to real-time as possible. I know that the data table stored in memory on the client is disconnected from the data table on the shared drive, so I must query again to get the updates.
I have two questions:
1) Is there an alternvative model I can use which is connected, and which will automatically reflect the updates in the data table on the shared drive?
2) If not, what is the best way to check for changes in the data table (so I can know when to call the data adapter fill method)? I am planning to poll the drive for a change to the .mdb file, raise an event and then fill the data adapter when the event is triggered. I am using this method successfully now to check for changes to a text file in another application, and I know how to implement it
I have a table (Projects) which is linked to projectVersions on projectID..projectVersions contains several columns on which I'd like to filter a returned project (and associated projectVersions) list. For example there is a "capacity" column and a "country" column. I am doing a filtered list of projects on one page and I'd like to include all projects where any one of the associated projectVersions has a capacity of 750ml and a country of "France" for example.It may be that a particular parameter is not set and so I pass a zero to indicate not to filter on that.I guess this needs some kind of subquery as when I try and do something like this: [code] it doesn't work as the "xxx" bit, being one-to-many, expects me to specify an item to get at the entities within and yet I want to query where ANY of the associated versions match one of the criteria.
View 1 RepliesI am starting with Linq to SQL in VB.NET, and trying to figure out how to make a simple query to a database.I want to do it all programaticly.I have made a connection to the database with a connectionstring, and this works fine - I can get a message if the database exists or not.But when I want to query a table, I am missing the part where I connest to the table. I have googled a lot to find an answer for thi, but [code]
View 2 RepliesI was able to use it for querying out info from an XML file but now i have to use the DBF file from a folder. where i can find out how to query out DBF table using LINQ. I basically need to get data from a column of a DBF table.
View 2 RepliesC# or VB.NET is fine. I'd like to count number of people for each country from the following tables with LINQ to SQL I have two tables, one is Countries and other is People. It's one to many relatoionship from Countries to People. ountries table column:CountryId,CountryName People:PeopleId,FullName,CountryId (a primary key from Country table and allowed null) I want to count how many people each country has and get something like the following result that shows only the country that has people. Because there are some countries that have no people in the People table.
[Code]...
Dim mydata = (From c In dc.Table Select New With {c.ID}).Count
any faster than this:
Dim mydata = (From c In dc.Table Select c).Count
[code].....
I want to populate a LINQ table from code, not DataBase.Is it possible ?System.Data.Linq.Table<Question> myquestions = new System.Data.Linq.Table<Question>();
View 2 RepliesI need to return the same results from linq as I get using SQL
SELECT DISTINCT Area, Region
FROM dbo.Regions
Union
SELECT null,'All'
Order by 1,2
I use this for showing an "All" selecting in a combo box
My current linq points to a view that does the union for me but I want to know how to do it right in linq. I can't figure out how to union a row for the null,'All' values.
Public Shared Function GetRegions(ByVal Area As String) As IEnumerable
Dim DB As New SiteDBDataContext
Return From values In DB.uv_Areas _
[Code].....
I have 2 tables Table1 with columns [BId,Name,Amount] Table2 with columns [CId,BId, ExpenseType,Expense]. BId Is the foreign key in Table2. The Amount field in Table1 is always higher than Expense in Table2. I need to update the values of Amount (increase or decrease) based on value of Expense and I want to do it in single query in LINQ. Eg If the Expense has to be updated with 200, I would decrease(negate) Amount value with 200. If Expense is reduce to 100 then the Amount is increased by a value of 100.
View 1 RepliesI´m trying to update my Students table record using LINQ to SQL. The problem is when one of the Properties of the object changed and 'PropertyChanging' Event is fired using 'SendPropertyChanging()' method.
student_id is a PK
data types are matched
Here is the full ArgumentException:
GenericArguments[2], 'System.String', on
'System.Data.Linq.Mapping.PropertyAccessor+Accessor`3[T,V,V2]'
violates the constraint of type 'V2'.
[code]....
I have a table that contains procedure codes among other data (let's call it "MyData"). I have another table that contains valid procedure codes, their descriptions, and the dates on which those codes are valid. Every time I want to report on MyData and include the procedure description, I have to do a lookup similar to this:
From m in dc.MyDatas _
Join p in dc.Procedures On m.proc_code Equals p.proc_code _
Where p.start_date <= m.event_date _
[Code]....
Is there a way to turn a complex lookup (i.e. a non-trivial join) like this into something SQL can recognize so that I can define it in one place and just reference the description as if it were a field in MyData? So far the only thing I can think of is to create a SQL view on MyData that does the linking and bring that into my data context, but I'd like to try to avoid that.
I have:
string s = "A=1,B=2,C=3";
I need the output in hashtable using LINQ. Hashtable should be filled as
["A"] | 1
["B"] | 2
["C"] | 3
I'm working on a form that has a few data grid views that are populated from LINQ queries, no problem there it works as it should however that sorting does not work. After doing some reading its because LINQ results do not support sorting.As I have the LINQ results already is there a way of copying the results into a dataset or datatable then binding the data grid view to that so sorting will work?
View 4 RepliesI've got a problem with Linq in VB.NET.I've created a .dbml file from my db, and everything looks good - relation "arrows" between tables are visible, etc.But when I want to use simple query (taken from 101 Linq Samples by MS):
Dim q = From h In dc.Hours, w In h.WorkType
I receive an error:
[code].....
My SQL Server database contains several views which are essentially filtered (WHERE) / ordered (ORDER BY) versions of some of the tables i.e. no joins.
An example would be my Downloads table, which has a view such as DownloadsOnlineOnly e.g.
SELECT * FROM Downloads WHERE Live = 1 ORDER BY FolderName ASC;
I can drag and drop these views onto my LINQ to SQL DataContext, and use LINQ to query these views and retrieve data fine...
But the foreign key relationships are not being picked up in my DataContext, so I've lost the ability to:
Dim dl as DownloadOnlineOnly = (From r in db.DownloadOnlineOnlies Select r).First
Dim fol as Folder = dl.Folder ' Syntax error as there is no association between
' DownloadOnlineOnly and Folder in my DataContext.
I understand why this is happening, but how can I get around this:
Without manually adding associations in my DataContext? Can I change the type of the Entity like changing the return type of an SP on the DataContext? Can I cast or convert between a DownloadOnlineOnly object and Download object? Or some other method?
In my programming task I've gone down a dark alley and wished I hadn't, but there is no turning back now.
I'm building up a SQL statement where the table name, column name and id value are retrieved from query string parameters i.e. ("SELECT [{0}] FROM [{1}] WHERE [Id] = {2};", c, t, id)
But it isn't as bad as it looks, I'm protected: Only authenticated users (i.e. signed in users) can execute the Page_Load I'm checking that both the table and the column exists beforehand (using GetSchema etc.)I'm checking that the Id is an integer beforehand All my tables have Id columns The database connection is reasonably secure
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I have 2 Tables , OrderDetails and Requests In my LINQ to SQL dbml file. OrderDetailsID is a foreign key in Requests Table.
I want to write the query to get the sum of UnitCost from OrderDetails based on OrderId. And If there is a row in Requests Table for each OrderDetailsID, and the Requests.Last.RequestType="Refund" I want to reduce the total refund amount from the main sum otherwise If there is no row based on OrderDetailsID, add to sum.
Here is the way I implement that. I am looking to prevent using "For each".
iRefund = (From od1 In dc.OrderDetails _
Where od1.OrderID =1 _
Select od1.UnitCost).Sum
[Code]....