I have a stored procedure that loops through a table and it may insert some records in to that table . Its working fine . I can see the changes in db using management studio .
The problem is after that i will call another stored procedure which will return a collection .But it always return a cached value or something like that .The latest changes in db not reflecting in the returned list .Any ideas?
EDIT
I am importing stored procedure to function using EF. All the operations i made is via EF.
Chek following code
TraktorumEntities db = new TraktorumEntities();
var test= db.GetAvailableAttributes(CategoryID).ToList(); // here i get cached values .How can i force to fetch data from data base
If you are querying using the same key, EF will have your results cached.
Note the section of "MergeOption.OverwriteChanges" here
Walkthrough: Mapping an Entity to Stored Procedures (Entity Data Model Tools)
You need to tell EF to 'get new data and overwrite the locally stored version' with this option.
Also you don't really tell us exactly how you are querying this data either. Is this a mapped stored procedure (mapped to an entity operation) or calling it directly on the context, or....?
EDIT
Try something along these lines
var test= db.GetAvailableAttributes(CategoryID)
test.MergeOption = MergeOption.NoTracking;
var results = test.ToList()
Did you leave some Database.SetInitializer in the Global Application_Start?
Related
I use Entity Framework in combination with an Oracle database. If I create a query like
myLinqStatement.ToListAsync()
I get wrong data returned as a result. If I change the statement to
myLinqStatement.AsNoTracking.ToListAsync()
I get the correct data.
I also checked the native SQL query, which is generated by myLinqStatement.ToListAsync(). The generated SQL query is correct, because I get the correct data.
So is there a problem in the mapping? And why is it working with AsNoTracking?
Thanks!
What AsNoTracking does is to retrieve the data without attaching it to the context, hence any changes you apply over the data do not take effect unless you attach it again so that EF knows it should track its changes.
The code snippets you've provided do not show the whole picture, from the moment a context is created, but is it possible that other parts of your code mutate data before you call myLinqStatement.ToListAsync()?
As you mention that myLinqStatement.AsNoTracking.ToListAsync() returns expected data, makes me assume that there are some side effects in your code that AsNoTracking simply is not aware so just returns whatever it finds in your db
I came across this question because I had a similar issue with Entity Framework Core querying a DB view, the issue was cause because view didn't have a key defined, after defining a key for the entity that map to that DB view, the query returned the same result in both cases (using AsNoTracking or without using it).
In T-SQL a key for a DB view can be defined this way:
CREATE UNIQUE CLUSTERED INDEX UQ_MyDBViewName_ColumnKey
ON dbo.MyDBViewName (ColumnKey);
And in code, you can map the key using the [Key] attribute in the corresponding property of the entity or using the EF fluent API. It will depend of what the project is using.
Either way, using AsNoTracking on a query that goes directly to a DB view makes a lot of sense. Also, if for some reason the query of the view does not allow us to define a key for that view, then the option is to use AsNoTracking.
Hope it helps anyone else having the same issue.
In the salesInvoice ssrs Report i have added a table called carTableEquipTmp which is not there by default, which I insert into along with the other tables(SalesinvoiceTmp and SalesinvoiceHeaderFooterTmp) in SalesInvoiceDP.InsertIntoSalesInvoiceTmp().
Even though my table carTableEquipTmp is getting successfully inserted into, the data doesn't show up on the report if i print a proforma report.
If i add test values to the carTableEquipTmp table in SalesInvoiceDP.processReport() they show up on the proforma invoice, but there's no way for me to get any parameters needed to set in the correct data into the table at this point. If i stop at this point in the debugger none of the data is present because processreport() is being called from a lower level in the code.
I think it might be a problem with maybe pack/unpack or that the proforma code runs from a server instance as the code run when it is proforma is quite different.
I can see that SalesInvoiceJournalPostBase.CreateReportData() creates an instance of salesInvoiceDP
salesInvoiceDP = new SalesInvoiceDP();
salesInvoiceDP.parmDataContract(salesInvoiceContract);
salesInvoiceDP.parmUserConnection(new UserConnection(true));
salesInvoiceDP.createData();
And that this might have something to do with it... but i still cant get the data i want in the carTableEquipTmp table.
So any idea on how to make Ax 2012 accept this new table i have added as it gets inserted into just like the other tables and there seems to be no problem...
I hope you guys can help.
The SalesInvoice report has two data classes you need to look at for the data provider, SalesInvoiceDP and SalesInvoiceDPBase. SalesInvoiceDPBase extends SrsReportDataProviderPreProcess, so there are a couple extra steps you need to take in order to add new datasources to the report.
In the salesInvoiceDP class, there is a method called useExistingReportData(), which re-inserts the pro-forma temp table data under a user connection, so the SrsReportDataProviderPreProcess framework will pick it up in your report. When the pro-forma process creates the report data, it doesn't insert with a user connection so it doesn't get added to the report. This method only gets called when the report is being run pro-forma.
You will need to add your temp table to this method, and follow the pattern for the other tables, so your code will look something like this:
//this is different from the buffer you insert your data with
CarTableEquipTmp localCarTableEquipTmp;
...
recordList = new RecordSortedList(tableNum(carTableEquipTmp));
recordList.sortOrder(fieldNum(carTableEquipTmp, RecId));
//You will need to add a field to relate your temp table
//to the current invoice journal, and insert it in
//InsertIntoSalesInvoiceTmp() if thats where you're inserting your table.
while select localCarTableEquipTmp
where localCarTableEquipTmp.JournalRecId == jourRecId
{
recordList.ins(localCarTableEquipTmp);
}
delete_from localCarTableEquipTmp
where localCarTableEquipTmp.JournalRecId == jourRecId;
recordList.insertDatabase(this.parmUserConnection());
This method re-inserts your data under the framework and deletes the original data. The data that was re-inserted will then get picked up by the framework and show in your report. If you open CarTableEquipTmp in the table browser, you will most likely see data still there from all the times you have tried running the report. This is why we have the delete_from operation after we re-insert the data. When data is inserted under a userConnection, it is automatically deleted when the report is finished
The other method you will want to modify is SalesInvoiceDP.setTableConnections(), and you will just need to add the following line:
CarTableEquipTmp.setConnection(this.parmUserConnection());
This will set the user connection for your table when running regular (not pro-forma). You will probably want to delete the data that is stored currently in your temp table using alt+F9 from the table browser.
Other than that it's all standard RDP stuff, but it sounds like you have that part working fine. Your temp table must be of type "Regular" for this to work.
I need to replace EF4.1 with ADO.NET. The data in our application is returned by stored procedures only. I need help re-writing calls like the following (in order to write a DAL for the application):
EF calling stored procedure:
using (var db = new NexGenContext())
{
SqlParameter param = new SqlParameter("#ReviewID", Id);
var issues = db.Database.SqlQuery<QuestionIssue>(
"SP_GetQuestionIssues #ReviewID", param).ToList();
return View(issues);
}
What is the equivalent in ADO.NET? Get data from the database and map to my models?
The closest ADO.NET technology to being an ORM without actually crossing the line is data sets. Data sets act very much like an ORM in the way you can access data directly from a table without looping through a cursor. Data Sets return lists directly and can track new data vs old.
This link is a pretty good overview:
http://www.c-sharpcorner.com/UploadFile/718fc8/working-with-dataset-in-ado-net/
This MVC datasets with viewbags stack thread specifically addresses using Data Sets in Models.
Basically, I have a LINQ database context and its model. As usually, I create the DB in the SQL context if the DB does not exist (the context is a singleton and on every access to it, this is checked).
Everything works well if I add data to the DB on the first launch. But if I don't insert any data during the first start of the app, on successive launches I get
SqlCeException:The specified table does not exist [TableName]
I don't know how more specifically I can explain it, but the exception comes immediately whenever I do a LINQ query on the second launch of the app if I don't insert any data on the first launch. If i do insert some data during the first launch, all is fine for the rest of the app's life time. Why would it be a bad thing to create the DBs and introduce the DB context, but not insert any data?
Here's my LINQ DB model:
https://github.com/kypeli/Podcatcher/blob/master/wp7/Podcatcher/ViewModels/PodcastSubscriptionModel.cs
Here's where I get the exception on second start if I didn't insert any data on the first launch:
https://github.com/kypeli/Podcatcher/blob/master/wp7/Podcatcher/PodcastSqlModel.cs#L64
It also strikes me that there's no API call to check if a table exists or not in LINQ, so I would have to assume "this should just work" - but it doesn't.
Any ideas? Thanks! :)
Update: I verified analyzing the .sdf file that indeed there are no tables created if I don't insert any data upon first launch of the app. As I see it:
This is a bug in LINQ-to-SQL. It should not crash if there are no tables present, but know that it should create them. Or deal with the case and create tables only when data is inserted.
I would need to insert some dummy data into SQL always on first launch, or...
Check if a table exists, if not, react to it by forcing LINQ-to-SQL to create them. But how?
I've dealt with this problem also, I've fixed it this way:
get the data context:
dbDataContext = new DBDataContext(DBConnectionString);
if( dbDataContext.DatabaseExists() == true)
//then try to get an entity:
System.Data.Linq.Table<Entity> entities = dbDataContext.Tablename;
//try to get an element from the entity:
IEnumerator<Entity> enumEntity = entities.GetEnumerator();
entities.GetEnumerator(); will always raise the exception "Table not found."
Just use a try/catch and in the catch scope delete the db and recreate it, because your DB is empty anyway :)
dbDataContext.DeleteDatabase();
dbDataContext.CreateDatabase();
dbDataContext.SubmitChanges();
I am using Sql tables without rowversion or timestamp. However, I need to use Linq to update certain values in the table. Since Linq cannot know which values to update, I am using a second DataContext to retrieve the current object from database and use both the database and the actual object as Input for the Attach method like so:
Public Sub SaveCustomer(ByVal cust As Customer)
Using dc As New AppDataContext()
If (cust.Id > 0) Then
Dim tempCust As Customer = Nothing
Using dc2 As New AppDataContext()
tempCust = dc2.Customers.Single(Function(c) c.Id = cust.Id)
End Using
dc.Customers.Attach(cust, tempCust)
Else
dc.Customers.InsertOnSubmit(cust)
End If
dc.SubmitChanges()
End Using
End Sub
While this does work, I have a problem though: I am also using StoredProcedures to update some fields of Customer at certain times. Now imagine the following workflow:
Get customer from database
Set a customer field to a new value
Use a stored procedure to update another customer field
Call SaveCustomer
What happens now, is, that the SaveCustomer method retrieves the current object from the database which does not contain the value set in code, but DOES contain the value set by the stored procedure. When attaching this with the actual object and then submit, it will update the value set in code also in the database and ... tadaaaa... set the other one to NULL, since the actual object does not contain the changed made by the stored procedure.
Was that understandable?
Is there any best practice to solve this problem?
If you make changes behind the back of the ORM, and don't use concurrency checking - then you are going to have problems. You don't show what you did in step "3", but IMO you should update the object model to reflect these changes, perhaps using OUTPUT TSQL paramaters. Or; stick to object-oriented.
Of course, doing anything without concurrency checking is a good way to lose data - so my preferred option is simply "add a rowversion". Otherwise, you could perhaps read the updated object out and merge things... somehow guessing what the right data is...
If you're going to disconnect your object from one context and use another one for the update, you need to either retain the original object, use a row version, or implement some sort of hashing routine in your database and retain the hash as part of your object. Of these, I highly recommend the Rowversion option as well. Using the current value as the original value like you are trying to do is only asking for concurrency problems.