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  • Linq: the linked objects are null, why?

    - by user46503
    Hello, I have several linked tables (entities). I'm trying to get the entities using the following linq: ObjectQuery<Location> locations = context.Location; ObjectQuery<ProductPrice> productPrice = context.ProductPrice; ObjectQuery<Product> products = context.Product; IQueryable<ProductPrice> res1 = from pp in productPrice join loc in locations on pp.Location equals loc join prod in products on pp.Product equals prod where prod.Title.ToLower().IndexOf(Word.ToLower()) > -1 select pp; This query returns 2 records, ProductPrice objects that have linked object Location and Product but they are null and I cannot understand why. If I try to fill them in the linq as below: res = from pp in productPrice join loc in locations on pp.Location equals loc join prod in products on pp.Product equals prod where prod.Title.ToLower().IndexOf(Word.ToLower()) > -1 select new ProductPrice { ProductPriceId = pp.ProductPriceId, Product = prod }; I have the exception "The entity or complex type 'PBExplorerData.ProductPrice' cannot be constructed in a LINQ to Entities query" Could someone please explain me what happens and what I need to do? Thanks

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  • Why is my ServiceOperation method missing from my WCF Data Services client proxy code?

    - by Kev
    I have a simple WCF Data Services service and I want to expose a Service Operation as follows: [System.ServiceModel.ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class ConfigurationData : DataService<ProductRepository> { // This method is called only once to initialize service-wide policies. public static void InitializeService(IDataServiceConfiguration config) { config.SetEntitySetAccessRule("*", EntitySetRights.ReadMultiple | EntitySetRights.ReadSingle); config.SetServiceOperationAccessRule("*", ServiceOperationRights.All); config.UseVerboseErrors = true; } // This operation isn't getting generated client side [WebGet] public IQueryable<Product> GetProducts() { // Simple example for testing return (new ProductRepository()).Product; } Why isn't the GetProducts method visible when I add the service reference on the client?

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  • NHibernate custom connection string configuration

    - by user177883
    I have a c# library project, that i configured using nhibernate, and I like people to be able to import this project and use the project. This project has FrontController that does all the work. I have a connection string in hibernate config file and in app.config file of another project. it would be nice for anyone to be able to set the connection string into this library project and use it. such as through a method which will take the connectiong string as parameter. or when creating a new instance of FrontController to pass the connection string to constructor. or if you have a better idea. How to do this? I d like this class library to use the same database of the project that s imported. How to set hibernate connection string programatically? same idea for log4net.

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  • Query in Datareader

    - by bala
    Hi All, In the below code, using (SqlDataReader dr = com.ExecuteReader(CommandBehavior.CloseConnection)) { while (dr.Read()) { _emailTemplate.EmailContent = dr["EMAILCONTENT"].ToString(); _emailTemplate.From = dr["EMAILFROM"].ToString(); _emailTemplate.Subject = dr["EMAILSUBJECT"].ToString(); } } I understand CommandBehavior.CloseConnection will close the connection object when datareader is closed. In the above code, when we use using with SqlDataReader, will it close the datareader before disposing it? in other other words, if i use using statement do i need to close the datareader manually?

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  • How to track changes in many MSSQL databases from .NET application?

    - by Yauheni Sivukha
    Problem: There are a lot of different databases, which is populated by many different applications directly (without any common application layer). Data can be accessed only through SP (by policy) Task: Application needs to track changes in these databases and react in minimal time. Possible solutions: 1) Create trigger for each table in each database, which will populate one table with events. Application will watch this table through SqlDependency. 2) Watch each table in each database through SqlDependency. 3) Create trigger for each table in each database, which will notify application using managed extension. Which is the best way?

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  • How to fill dataset when sql is returning more than one table

    - by Shantanu Gupta
    How to fill multiple tables in a dataset. I m using a query that returns me four tables. At the frontend I am trying to fill all the four resultant table into dataset. Here is my Query. Query is not complete. But it is just a refrence for my Ques Select * from tblxyz compute sum(col1) suppose this query returns more than one table, I want to fill all the tables into my dataset I am filling result like this con.open(); adp.fill(dset); con.close(); Now when i checks this dataset. It shows me that it has four tables but only first table data is being displayed into it. rest 3 dont even have schema also. What i need to do to get desired output

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  • Entity Framework Performance Problem

    - by Steve Horn
    I'm hoping that someone can help me understand how to overcome a performance problem I'm running into with the latest version of the Entity Framework. In my test, I created my model from a database consisting of around 80 tables. The problem that I'm running into is that the cost of the very first query I run on a thread is very expensive. If I run without pre-compiling views the first query takes anywhere from 5800 to 6600 milliseconds. If I pre-compile the views (see this article) I can get the initial query cost down to about 2800 to 3200 milliseconds. 3 seconds for each request is still unacceptable for my needs. Subsequent queries are very fast. Can you please help me understand how to eliminate the poor performance of the initial query? I'm using the version of entity framework that ships with Visual Studio 2010 RC.

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  • Most efficient sorting of calculation on DataTable column calculation

    - by byte
    Lets say you have a DataTable that has columns of "id", "cost", "qty": DataTable dt = new DataTable(); dt.Columns.Add("id", typeof(int)); dt.Columns.Add("cost", typeof(double)); dt.Columns.Add("qty", typeof(int)); And it's keyed on "id": dt.PrimaryKey = new DataColumn[1] { dt.Columns["id"] }; Now what we are interested in is the cost per quantity. So, in other words if you had a row of: id | cost | qty ---------------- 42 | 10.00 | 2 The cost per quantity is 5.00. My question then is, given the preceeding table, assume it's constructed with many thousands of rows, and you're interested in the top 3 cost per quantity rows. The information needed is the id, cost per quantity. You cannot use LINQ. In SQL it would be trivial; how BEST (most efficiently) would you accomplish it in C# without LINQ?

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  • C# Gridview - Checking if a column already exists when adding a new column fails

    - by Nir
    I have a GridView with 10 columns. On a certain condition, I want to add a new column called "Expiration Date". The problem is that when the user presses "Search" again (Postback) the column is added again. I check before adding the column, to see if it already exists: BoundField dtExp = new BoundField {DataField = "DateTimeExpired", HeaderText = "Expiration Date", DataFormatString = "{0:d}"}; if (!grid.Columns.Contains(dtExp)){grid.Columns.Add(dtExp);} But the problem is that even if the column already exists, "Contains" returns false. What am I doing wrong? Thanks!

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  • How to return a recordset from a function

    - by Scott
    I'm building a data access layer in Excel VBA and having trouble returning a recordset. The Execute() function in my class is definitely retrieving a row from the database, but doesn't seem to be returning anything. The following function is contained in a class called DataAccessLayer. The class contains functions Connect and Disconnect which handle opening and closing the connection. Public Function Execute(ByVal sqlQuery as String) As ADODB.recordset Set recordset = New ADODB.recordset Dim recordsAffected As Long ' Make sure we are connected to the database. If Connect Then Set command = New ADODB.command With command .ActiveConnection = connection .CommandText = sqlQuery .CommandType = adCmdText End With ' These seem to be equivalent. 'Set recordset = command.Execute(recordsAffected) recordset.Open command.Execute(recordsAffected) Set Execute = recordset recordset.ActiveConnection = Nothing recordset.Close Set command = Nothing Call Disconnect End If Set recordset = Nothing End Function Here's a public function that I'm using in cell A1 of my spreadsheet for testing. Public Function Scott_Test() Dim Database As New DataAccessLayer 'Dim rs As ADODB.recordset 'Set rs = CreateObject("ADODB.Recordset") Set rs = New ADODB.recordset Set rs = Database.Execute("SELECT item_desc_1 FROM imitmidx_sql WHERE item_no = '11001'") 'rs.Open Database.Execute("SELECT item_desc_1 FROM imitmidx_sql WHERE item_no = '11001'") 'rs.Open ' This never displays. MsgBox rs.EOF If Not rs.EOF Then ' This is displaying #VALUE! in cell A1. Scott_Test = rs!item_desc_1 End If rs.ActiveConnection = Nothing Set rs = Nothing End Function What am I doing wrong?

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  • Is it possible to easily convert SqlCommand to T-SQL string ?

    - by Thomas Wanner
    I have a populated SqlCommand object containing the command text and parameters of various database types along with their values. What I need is a T-SQL script that I could simply execute that would have the same effect as calling the ExecuteNonQuery method on the command object. Is there an easy way to do such "script dump" or do I have to manually construct such script from the command object ?

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  • WCF Data Services - neither .Expand or .LoadProperty seems to do what I need

    - by TomK
    I am building a school management app where they track student tardiness and absences. I've got three entities to help me in this. A Students entity (first name, last name, ID, etc.); a SystemAbsenceTypes entity with SystemAbsenceTypeID values for Late, Absent-with-Reason, Absent-without-Reason; and a cross-reference table called StudentAbsences (matching the student IDs with the absence-type ID, plus a date, and a Notes field). What I want to do is query my entities for a given student, and then add up the number of each kind of Absence, for a given date range. I prepare my currentStudent object without a problem, then I do this... Me.Data.LoadProperty(currentStudent, "StudentAbsences") 'Loads the cross-ref data lblDaysLate.Text = (From ab In currentStudent.StudentAbsences Where ab.SystemAbsenceTypes.SystemAbsenceTypeID = Common.enuStudentAbsenceTypes.Late).Count.ToString ...and this second line fails, complaining it has no value for an object. I presume the problem is that while it DOES see that there are (let's say) four absences for the currentStudent (ie, currentStudent.StudentAbsences.Count = 4) -- it can't yet "peer into" each one of the absences to look at its type. How do I use .Expand or .LoadProperty to make this happen? I tried fiddling with .LoadProperty but it doesn't take a two-level syntax like so... Data.LoadProperty(currentStudent,"StudentAbsences.SystemAbsenceTypeID") or the like. Is there some other technique?

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  • Should DAL always return business objects in MVP

    - by Chathuranga
    In Model View Presenter (MVP) pattern, it is said that our DAL always should returns business models. But let's say if I want to get just a number from database like the last ClientID (the latest clients ID) which is a string, should my DAL method returns a ClientInfo object which has about 10 other fields as well like ClientName, Address etc.? If I want to get a list of business objects from my DAL, is it acceptable to do it as follows or better to get a DataTable from DAL and then in the applications BLL, converts it a List? public List<Employee> GetNewEmployees() { string selectStatement = "SELECT Employee.Emp_ID, Employee.Initials + ' ' + Employee.Surname AS Name,..."; using (SqlConnection sqlConnection = new SqlConnection(db.GetConnectionString)) { using (SqlCommand sqlCommand = new SqlCommand(selectStatement, sqlConnection)) { sqlConnection.Open(); using (SqlDataReader dataReader = sqlCommand.ExecuteReader()) { List<Employee> list = new List<Employee>(); while (dataReader.Read()) { list.Add ( new EpfEtfMaster { EmployeeID = (int) dataReader ["emp_id"], EmployeeName = (string) dataReader ["Name"], AppointmentDate = (DateTime) dataReader["appointment_date"], }); } return list; } } } }

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  • how to get the table primary key after saving an item via AdoNetServiceProxy

    - by Jronny
    I have a js proxy class: function ProxyClass() { this.Properties = null; this.Insert = function () { try { var service = new Sys.Data.AdoNetServiceProxy("/WcfDataService1.svc"); service.insert(this, "TheTable"); } catch (ex) { alert("error: " + ex); } }; } The insert has been working, but I need to get the primary key of TheTable right after. How could we be able to pull it up? Thanks a lot

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  • crash with CoUnintailize() api of COM

    - by jbp117
    My main process(main.exe) initilaized COM library and created a thread which creates a new process(p1.exe) this new process is again initializing COM library and after making all references as zero unintialized COM here.. the unintailezed COM in the main process (i.e main.exe) also.... When i run p1.exe individually it is successful.. but it is crashing when i create a process for p1.exe from main.exe

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  • Can't connect twice to linked table using ACE/JET driver

    - by Tmdean
    I'm trying to connect to an MS Access database linked table in VBScript. It works fine connecting the first time on one connection but if I close that connection and open a new one in the same script it gives me an error. test.vbs(13, 1) Microsoft Office Access Database Engine: ODBC--connection to '{Oracle in OraClient10g_home1}DB_NAME' failed. This is some code that triggers the error. TABLE_1 is an ODBC linked table in the test.mdb file. Dim cnn, rs Set cnn = CreateObject("ADODB.Connection") cnn.Open "Provider=Microsoft.ACE.OLEDB.12.0;Data source=test.mdb" Set rs = cnn.Execute("SELECT * FROM [TABLE_1]") rs.Close cnn.Close Set cnn = CreateObject("ADODB.Connection") cnn.Open "Provider=Microsoft.ACE.OLEDB.12.0;Data source=test.mdb" Set rs = cnn.Execute("SELECT * FROM [TABLE_1]") '' crashes here rs.Close cnn.Close This error does not occur if I try to access an ordinary Access table. Right now I'm thinking it's a bug in the Oracle ODBC driver.

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  • SQL Server SELECT stored procedure according to combobox.selectedvalue

    - by Jay
    In order to fill a datagridview according to the selectedvalue of a combobox I've tried creating a stored procedure. However, as I'm not 100% sure what I'm doing, depending on the WHERE statement at the end of my stored procedure, it either returns everything within the table or nothing at all. This is what's in my class: Public Function GetAankoopDetails(ByRef DisplayMember As String, ByRef ValueMember As String) As DataTable DisplayMember = "AankoopDetailsID" ValueMember = "AankoopDetailsID" If DS.Tables.Count > 0 Then DS.Tables.Remove(DT) End If DT = DAC.ExecuteDataTable(My.Resources.S_AankoopDetails, _Result, _ DAC.Parameter(Const_AankoopID, AankoopID), _ DAC.Parameter("@ReturnValue", 0)) DS.Tables.Add(DT) Return DT End Function Public Function GetAankoopDetails() As DataTable If DS.Tables.Count > 0 Then DS.Tables.Remove(DT) End If DT = DAC.ExecuteDataTable(My.Resources.S_AankoopDetails, _Result, _ DAC.Parameter(Const_AankoopID, AankoopID), _ DAC.Parameter("@ReturnValue", 0)) DS.Tables.Add(DT) Return DT End Function This is the function in the code behind the form I've written in order to fill the datagridview: Private Sub GridAankoopDetails_Fill() Try Me.Cursor = Cursors.WaitCursor dgvAankoopDetails.DataSource = Nothing _clsAankoopDetails.AankoopDetailsID = cboKeuze.SelectedValue dgvAankoopDetails.DataSource = _clsAankoopDetails.GetAankoopDetails Catch ex As Exception MessageBox.Show("An error occurred while trying to fill the data grid: " & ex.Message, "Oops!", MessageBoxButtons.OK) Finally Me.Cursor = Cursors.Default End Try End Sub And finally, this is my stored procedure: (do note that I'm not sure what I'm doing here) USE [Budget] GO /****** Object: StoredProcedure [dbo].[S_AankoopDetails] Script Date: 04/12/2010 03:10:52 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[S_AankoopDetails] ( @AankoopID int, @ReturnValue int output ) AS declare @Value int set @Value =@@rowcount if @Value = 0 begin SELECT dbo.tblAankoopDetails.AankoopDetailsID, dbo.tblAankoopDetails.AankoopID, dbo.tblAankoopDetails.ArtikelID, dbo.tblAankoopDetails.Aantal, dbo.tblAankoopDetails.Prijs, dbo.tblAankoopDetails.Korting, dbo.tblAankoopDetails.SoortKorting, dbo.tblAankoopDetails.UitgavenDeelGroepID FROM dbo.tblAankoopDetails INNER JOIN dbo.tblAankoop ON dbo.tblAankoopDetails.AankoopID = dbo.tblAankoop.AankoopID INNER JOIN dbo.tblArtikel ON dbo.tblAankoopDetails.ArtikelID = dbo.tblArtikel.ArtikelID INNER JOIN dbo.tblUitgavenDeelGroep ON dbo.tblAankoopDetails.UitgavenDeelGroepID = dbo.tblUitgavenDeelGroep.UitgavenDeelGroepID WHERE dbo.tblAankoopDetails.Deleted = 0 and dbo.tblAankoopDetails.AankoopID = @AankoopID ORDER BY AankoopID if @@rowcount >0 begin set @ReturnValue=999 end else begin set @ReturnValue=997 end end if @Value >0 begin --Dit wil zeggen dat ik een gebruiker wil ingeven die reeds bestaat. (998) set @ReturnValue=998 end Does anyone know what I need to do to resolve this?

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  • Passing an TAdoDataset as parameter using TADOStoredProc

    - by Salvador
    i have an oracle stored procedure with 2 parameters declarated as input cursors. how i can assign this parameters the TADOStoredProc component? ORACLE PROCEDURE MYSTOREDPROCEDURE(P_HEADER IN TCursor, P_DETAL IN TCursor, P_RESULT OUT VARCHAR2) BEGIN //My code goes here END; Delphi function TMyClass.Add(Header, Detail: TADODataSet;var _Result: string): boolean; Var StoredProc : TADOStoredProc; begin Result:=False; StoredProc:=TADOStoredProc.Create(nil); try StoredProc.Connection :=ADOConnection1; StoredProc.ProcedureName:='MYSTOREDPROCEDURE'; StoredProc.Parameters.Refresh; StoredProc.Parameters.ParamByName('P_HEADER').Value :=Header;//How can assign this parameter? try StoredProc.Open; _Result:=VarToStrNull(StoredProc.Parameters.ParamByName('P_RESULT').Value); StoredProc.Close; Result:=True; except on E : Exception do begin _Result:=E.Message; //exit; end; end; finally StoredProc.Free; end; end;

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  • crash with CoUnintialize() api of COM

    - by jbp117
    My main process(main.exe) initilaized COM library and created a thread which creates a new process(p1.exe) this new process is again initializing COM library and after making all references as zero unintialized COM here.. the unintailezed COM in the main process (i.e main.exe) also.... When i run p1.exe individually it is successful.. but it is crashing when i create a process for p1.exe from main.exe

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  • How can i query for null values in entity framework?

    - by AZ
    I want to execute a query like this var result = from entry in table where entry.something == null select entry; and get an IS NULL generated. Edited: After the first two answers i feel the need to clarify that I'm using Entity Framework and not Linq to SQL. The object.Equals() method does not seem to work in EF. Edit no.2: The above query works as intended. It correctly generates IS NULL. My production code however was var value = null; var result = from entry in table where entry.something == value select entry; and the generated SQL was something = @p; @p = NULL. It seems that EF correctly translates the constant expression but if a variable is involved it treats it just like a normal comparison. Makes sense actually. I'll close this question

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  • Restoring database with SMO - Reporting progress problems

    - by madlan
    I'm using the below to restore a database in VB.NET. This works but causes the interface to lockup if the user clicks anything. Also, I cannot get the progress label to update incrementally, it's blank until the backup is complete then displays 100% Sub DoRestore() Dim svr As Server = New Server("Server\SQL2008") Dim res As Restore = New Restore() res.Devices.AddDevice("C:\MyDB.bak", DeviceType.File) res.Database = "MyDB" res.RelocateFiles.Add(New RelocateFile("MyDB_Data", "C:\MyDB.mdf")) res.RelocateFiles.Add(New RelocateFile("MyDB_Log", "C:\MyDB.ldf")) res.PercentCompleteNotification = 1 AddHandler res.PercentComplete, AddressOf ProgressEventHandler res.SqlRestore(svr) End Sub Private Sub ProgressEventHandler(ByVal sender As Object, ByVal e As PercentCompleteEventArgs) Label3.Text = "" ProgressBar.Value = e.Percent LblProgress.Text = e.Percent.ToString End Sub

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