I am doing a small project to learn how to use DataSet but i have a small problem. Consider following code:
foreach (DatabaseDataSet.ApplicationRow rowApplication in database.Application)
{
if (rowApplication.AID.ToString() == lblIDApplication.Text)
{
rowApplication.Date= tbApplicationDatum.Text;
rowApplication.Status = tbApplicationStatus.Text;
applicationAdapter.Update(rowApplication);
break;
}
}
I don't know why but the database doesn't get updated. The DataRow is being updated as when I call the data again I see the new value. But when I re-run my application it's back to it's old value again. Any help?
EDIT: I'm working with strongly typed DataSet
You need to call the Update method of your adapter to propogate the changes
AcceptChanges only updates the changes in memory for the row and does not migrate those to the database
MSDN
AcceptChanges and RejectChanges only apply to DataRow related changes
(that is, Add, Remove, Delete, and Modify). They are not applicable to
schema or structural changes.
Calling AcceptChanges will not replicate these changes back to the
data source if the DataSet was filled using a DataAdapter. In that
situation, call Update instead
See Updating Data Sources with DataAdapters for more information
Its important to remember that the DataSet is a 'local copy' of the data not a 'live link' to the DB. If your DataSet is populated by a IDataAdaptor (say a TableAdaptor) for example you need to call the DataAdaptors Update method passing in the Updated dataset to sync the results back to the underlying DB.
Also I would suspect you DONT want to be doing 'new ApplicationTableAdapter()' because typically you would want to update with the TableAdaptor you populated with, at the least you would need to ensure you had the correct connection, query etc set up.
SOLUTION: It happens that nothing was wrong with the code. I had two ConnectionString defined in App.config. I forgot to remove the first one after I removed a previous database that had errors in it. Upon removing the first ConnectionString, everything worked.
Related
I have a dataset called "titulos" and have 1 table there called "tb"
with the columns with the name "titulo","titulo 2" and "titulo3".
I'm trying to do an insertion of rows in the event onclick of a button
but for some reason my code doesn't work!
My dataset is on a xsd file and I am using visual studio 2013 with c#.
I already tried this code but I don't know how to apply in my situation:
NorthwindDataSet.CustomersRow newCustomersRow =
northwindDataSet1.Customers.NewCustomersRow();
newCustomersRow.CustomerID = "ALFKI";
newCustomersRow.CompanyName = "Alfreds Futterkiste";
northwindDataSet1.Customers.Rows.Add(newCustomersRow);
The problem is that shows an error saying it does not recognize the dataset...
The erros is : "The name " Ds_Admissibilidade" does not exist in the current context
A DataSet is a disconnected copy of the data. It forgets if the data originated from database, an xml file or anything else. When you add rows to the DataSet, you only change the in-memory copy, not the original source.
You need some mechanism to update the source. For databases, a table adapter or dataadapter will do this for you. For a file source, you need to serialize the DataSet to the file, much the reverse of the way you read in in first place.
Hope this helps :)
DataRow newRow = titulos.Tables["tb"].NewRow();
newRow["titulo1"] = "titulo1";
newRow["titulo2"] = "titulo2";
newRow["titulo3"] = "titulo3";
titulos.Tables["tb"].Rows.Add(newRow);
Make sure you're setting all the values of the non nullable parameters. If you're using another instance of the dataset "titulos" use ImportRow instead of Add function.
I have a group of data sets and they are all editable, what I need is a function that copies all of the information in the data tables and saves it back into the data set or as a seperate xml.
Ultimately, a DataTable is updatable. I can write
ds.Tables[0].Rows[0][0] = "Test"
(where ds is a DataSet) and that will update row 1, column 1 of the first DataTable within the DataSet. What I do from there with it is my choice, but the change is there in the in-memory copy of the DataSet.
If you're populating from a database via a DataAdapter, you can then call Update() to commit the changes back to the database, but if you're not in that scenario, then your change will remain in memory until you either dispose of the DataSet/s or go back off to the source to fetch them again.
I think the bottom line here is that you don't need a function to update DataTables, as they are inherently capable of being updated.
I have a DataGridView. It uses a BindingSource, a DataTable in a DataSet, and a TableAdapter to add/change/delete data in a table. It worked OK, but stopped working when I added a field/column, and I can't figure out what I did or how fix it.
The user can add a new row at the bottom of the DataGridView, but when he goes to save, the row disappears and is not saved. In addition, if he tries to type a second new row, the first new row disappears.
Existing Rows can be changed and saved back to the database successfully.
I've been asked for code. OK, here is code. (I've eliminated some error checking done by scanning dtDep) The point that after the third line is executed, there are no rows in dtDep even though a new row had been entered into the DataGridView. If a row had been retrieved, it would be in dtDep and the database table updated by the last statement.
this.Validate();
bsBelkDep.EndEdit();
DataTable dtDep = dsBelk.Tables["belk_elig_dep"];
int n = belk_elig_depTableAdapter.Update(this.dsBelk.belk_elig_dep);
It was a problem with the DataGridView, but I don't know what. I started deleting and re-creating the various object, and after the I recreated the DataGridView, it worked OK. Which was a pain because I have to do significant reformatting, but at least it works.
This is a very old question and I have no way of knowing if it was the OP's original problem, but I had the exact same scenario and this is how I resolved it.
For background: I have a WinForms application built using datasets and an Access database. I migrated that to use Sqlite and anything but datasets. To avoid destroying the application completely, first I copied the strongly typed data tables out, tweaked them to account for changes in the schema and then used PetaPoco to perform the data operations. That worked fine for a single test conversion.
The trouble arose when I wanted to move on and convert all data tables - I wasn't happy manually writing the logic for converting to and from typed data rows and POCOs, so I fell back to writing old school T4 templates to generate typed DataTable, DataRow classes and the necessary remapping code.
Worked a treat - for editing or removing data. But new rows disappeared on "creation", the binding navigator count didn't increment, and of course, when saving, I didn't detect any rows with the RowState of DataRowState.Added. The grid at start up was subtly different - a blank value in all columns instead of a negative number in the ID column. In hindsight, that should have been a big clue.
On reverting the behaviour back to the manually extracted typed class the grid started working again so it was clearly an error in the new code.
End of background; tldr;
The cause of the issue, in my case, was that the my Id column didn't have the AutoIncrement property set. As soon as I configured that to be true (along with setting AutoIncrementSeed and AutoIncrementStep to -1, although neither are required) new rows started being correctly added to the table.
I have what I am sure is a typical situation.
I have a DB and I have an XML document of data. I'd like to combine the 2 and update the db.
I have 'fill'ed a DataSet and/or DataTable with the DB data, and if I modify the data in that structure i can call Update and all is well.
Here is what I have.
con.Open();
adapter.Fill(ds2, "BASIC");
ds.ReadXmlSchema(#"C:\asis.xsd");
ds.ReadXml("c:\\asis.xml");
// This is the XML data
DataTable loadeddt = ds.Tables["BASIC"];
// This is from the DB
DataTable dbdt = ds2.Tables["BASIC"];
// I want to put the data from xml into the dataset from the DB
dbdt.Merge(loadeddt);
// I want to them put those changes in the db
adapter.Fill(dbdt);
Here is what happens, before I loaded the XSD I got an exception saying that types didn't match.
Now I get nothing, no exception no changes. neither of the DataTable show changes and neither does the DB.
Can anyone offer any suggestions?
If I change the last line to Update I get the following:
Violation of PRIMARY KEY constraint 'PK_BASIC'. Cannot insert duplicate key in object 'dbo.BASIC'.
I have noticed that if you do a .Rows.Count pre/post the merge the record count goes from 10 to 20 so it is combining them... not merging them. argh!
FUTHER MORE if I call dbdt.GetChanges(); it returns the whole lot. if i accept changes and update it still does nothing.
You should call Update instead of Fill for this line:
// I want to them put those changes in the db
adapter.Fill(dbdt);
After question update:
You're inserting a key that already exists. Either the merge is telling the adapter that it should insert when it should update or the DB fill isn't returning all rows. Hard to tell with what's given.
This seems like somewhat of a hack but if you know what rows should be considered updates, you can call SetModified on those rows.
Right guys,
I found this article:
http://www.dotnetmonster.com/Uwe/Forum.aspx/dotnet-ado-net/14201/Merge-function-in-DataSet
Basically the XSD needs to completely describe the primary key for the merge to work.
Essentially I needed to add:
<xs:key name="ROOTKey1" msdata:PrimaryKey="true">
<xs:selector xpath=".//BASIC" />
<xs:field xpath="MEMBNO" />
</xs:key>
I've created a new project in .Net (2010 4.0) and added an SDF data file. I've generated a dataset and created a table in it (and I believe generated the Fill and other methods).
In code, I'm trying to add a row to the database.
eBureauScrubber.App_Data.matchingtempDataSet ds = new App_Data.matchingtempDataSet();
eBureauScrubber.App_Data.matchingtempDataSet.ctfFileRow row = ds.ctfFile.NewctfFileRow();
row.Address = "123 Main St.";
row.City = "Overland Park";
row.FirstName = "Matt";
row.LastName = "Dawdy";
row.rownum = 1;
EDIT: Added the next bit of code.
ds.ctfFile.Rows.Add(row);
ds.ctfFile.AcceptChanges();
ds.AcceptChanges();
eBureauScrubber.App_Data.matchingtempDataSetTableAdapters.ctfFileTableAdapter ctfa = new App_Data.matchingtempDataSetTableAdapters.ctfFileTableAdapter();
ctfa.Update(ds.ctfFile);
This runs fine. However, after the program completes, the data is not persisted in the database. What am I missing?
EDIT: I've tried all different combinations of AcceptChanges() on the datatable, the dataset, running update() before, after, etc. I'm missing something huge here. I'm not even sure it is connecting to the "right" database. Maybe that's my problem.
EDIT 2: Here's what I did to get this to work (it's still funky, though).
Change the properties of my DB file in App_Data to "Do Not Copy"
Manually copy that db file to bin\debug\app_data
Use the data adapter's fill method to fill the ds.ctfFile data table.
Create a row (.NewctfFileRow())
Set values on that row.
ds.ctfFile.Rows.Add(row)
ds.ctfFile.AcceptChanges();
ds.AcceptChanges();
Call the adapater's update method.
Now, the data is in my database file (in bin\debug\app_data), but I can't see it because the Data Sources connection. I'm still trying to find out how to do that.
It should have generated a TableAdapter class with a .Update() method that you have to call to save data in your database. See MSDN for some examples.