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  • why DbCommandBuilder (Oracle) produces weird WHERE-clause to UpdateCommand?

    - by matti
    I have a table HolidayHome in oracle db which has unique db index on Id (I haven't specified this in the code in any way for adapter/table/dataset, don't know if i should/can). DbDataAdapter.SelectCommand is like this: SELECT Id, ExtId, Label, Location1, Location2, Location3, Location4, ClassId, X, Y, UseType FROM HolidayHome but UpdateCommand generated by DbCommandBuilder has very weird where clause: UPDATE HOLIDAYHOME SET ID = :p1, EXTID = :p2, LABEL = :p3, LOCATION1 = :p4, LOCATION2 = :p5, LOCATION3 = :p6, LOCATION4 = :p7, CLASSID = :p8, X = :p9, Y = :p10, USETYPE = :p11 WHERE ((ID = :p12) AND ((:p13 = 1 AND EXTID IS NULL) OR (EXTID = :p14)) AND ((:p15 = 1 AND LABEL IS NULL) OR (LABEL = :p16)) AND ((:p17 = 1 AND LOCATION1 IS NULL) OR (LOCATION1 = :p18)) AND ((:p19 = 1 AND LOCATION2 IS NULL) OR (LOCATION2 = :p20)) AND ((:p21 = 1 AND LOCATION3 IS NULL) OR (LOCATION3 = :p22)) AND ((:p23 = 1 AND LOCATION4 IS NULL) OR (LOCATION4 = :p24)) AND (CLASSID = :p25) AND (X = :p26) AND (Y = :p27) AND (USETYPE = :p28)) all these fields that have like: ((:p17 = 1 AND LOCATION1 IS NULL) OR (LOCATION1 = :p18)) are defined in oracle db like this: LOCATION1 VARCHAR2(30) so they allow null values. the code looks like this: static bool CreateInsertUpdateDeleteCmds(DbDataAdapter dataAdapter) { DbCommandBuilder builder = _trgtProvFactory.CreateCommandBuilder(); builder.DataAdapter = dataAdapter; // Get the insert, update and delete commands. dataAdapter.InsertCommand = builder.GetInsertCommand(); dataAdapter.UpdateCommand = builder.GetUpdateCommand(); dataAdapter.DeleteCommand = builder.GetDeleteCommand(); } what to do? The UpdateCommand is utter madness. Thanks & Best Regards: Matti

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  • DataView Vs DataTable.Select()

    - by Aseem Gautam
    Considering the code below: Dataview someView = new DataView(sometable) someView.RowFilter = someFilter; if(someView.count > 0) { …. } Quite a number of articles which say Datatable.Select() is better than using DataViews, but these are prior to VS2008. Solved: The Mystery of DataView's Poor Performance with Large Recordsets Array of DataRecord vs. DataView: A Dramatic Difference in Performance So in a situation where I just want a subset of datarows based on some filter criteria(single query) and what is better DataView or DataTable.Select()?

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  • Can a stateless WCF service benefit from built-in database connection pooling?

    - by vladimir
    I understand that a typical .NET application that accesses a(n SQL Server) database doesn't have to do anything in particular in order to benefit from the connection pooling. Even if an application repeatedly opens and closes database connections, they do get pooled by the framework (assuming that things such as credentials do not change from call to call). My usage scenario seems to be a bit different. When my service gets instantiated, it opens a database connection once, does some work, closes the connection and returns the result. Then it gets torn down by the WCF, and the next incoming call creates a new instance of the service. In other words, my service gets instantiated per client call, as in [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]. The service accesses an SQL Server 2008 database. I'm using .NET framework 3.5 SP1. Does the connection pooling still work in this scenario, or I need to roll my own connection pool in form of a singleton or by some other means (IInstanceContextProvider?). I would rather avoid reinventing the wheel, if possible.

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  • Association not imported in EF4 designer for non-primary key

    - by Rommel Manalo
    The relationship 'FK_EXTERNAL_ISMARKETI_MARKETIN' has columns that are not part of the key of the table on the primary side of the relationship. The relationship was excluded. USE [Instruments.UnitTest] GO ALTER TABLE [Instr].[ExternalIdentification] WITH CHECK ADD CONSTRAINT [FK_EXTERNAL_ISMARKETI_MARKETIN] FOREIGN KEY([InstrumentID], [MarketInstrumentID]) REFERENCES [Instr].[MarketInstrument] ([InstrumentID], [MarketInstrumentID]) GO ALTER TABLE [Instr].[ExternalIdentification] CHECK CONSTRAINT [FK_EXTERNAL_ISMARKETI_MARKETIN] GO I'm using an association for NON-PRIMARY KEY columns, is this possible in the EF4?

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  • DataReader-DataSet Hybrid solution

    - by G33kKahuna
    My solution architects and I have exhausted both pure Dataset and Datareader solutions. Basically we have a Microsoft.NET 2.0 windows service application that pulls data based on a query and processes additional tasks per record; almost a poor mans workflow system. The recordsets are broader (in terms of the columns) and deeper (in terms of number of records). We observed that DataSet performs much better in terms of performance but runs into contraints as # of records increase say 100K+ we start seeing System.OutOfMemoryException on a 4G machine with processModel configured to run at memoryLimit set to 85. Since this is a multi-threaded app, there could be multiple threads processing different queries and building different DataSets, so we run into the exception sooner in that case DataReader on the other hand works but is a lot slower and hits other contraints; if there is some sort of disconnect it has to start over again or leaves open connections on the DB side and worst case takes down the service completely etc. So, we decided the best option would be some sort of hybrid solution. I'm open to guidance and suggestions. Are there any hybrid solutions available? Any other suggestions

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  • How to select top n rows from a datatable/dataview in asp.net

    - by skamale
    How to select top n rows from a datatable/dataview in asp.net.currently I am using the following code by passing the table and number of rows to get the records but is there a better way. public DataTable SelectTopDataRow(DataTable dt, int count) { DataTable dtn = dt.Clone(); for (int i = 0; i < count; i++) { dtn.ImportRow(dt.Rows[i]); } return dtn; }

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  • NHibernate 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. 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. 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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  • Can I use a single DateTime field on the Entity Framework model side when the value is stored in a set of Int fields in the actual database?

    - by Ivan
    The actual table in the database has separate integer fields for storing year, month, day, hour and minute values (all in UTC) (seconds and milliseconds are irrelevant for my task and considered equal to zero). Needless to say it would be of great convenience to have just one field of DateTime type on the application side and hide all the conversion under the cover of the Entity Framework model code. Any directions on how to do that? I am not very experienced with Entity Framework yet.

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  • C# SQL Data Adapter System.Data.StrongTypingException

    - by René
    I get my data from SQL to Dataset with Fill. It's just one table with two columns (CategoryId (int) and CategoryName (varchar)). When I look at my dataset after fill method, CategoryId Columns seems to be correct. But in the CategoryName I have a *System.Data.StrongTypingExceptio*n. What could that mean? Any Ideas?

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  • Why is sql server giving a conversion error when submitting date.today to a datetime column?

    - by kpierce8
    I am getting a conversion error every time I try to submit a date value to sql server. The column in sql server is a datetime and in vb I'm using Date.today to pass to my parameterized query. I keep getting a sql exception Conversion failed when converting datetime from character string. Here's the code Public Sub ResetOrder(ByVal connectionString As String) Dim strSQL As String Dim cn As New SqlConnection(connectionString) cn.Open() strSQL = "DELETE Tasks WHERE ProjID = @ProjectID" Dim cmd As New SqlCommand(strSQL, cn) cmd.Parameters.AddWithValue("ProjectID", 5) cmd.ExecuteNonQuery() strSQL = "INSERT INTO Tasks (ProjID, DueDate, TaskName) VALUES " & _ " (@ProjID, @TaskName, @DueDate)" Dim cmd2 As New SqlCommand(strSQL, cn) cmd2.CommandText = strSQL cmd2.Parameters.AddWithValue("ProjID", 5) cmd2.Parameters.AddWithValue("DueDate", Date.Today) cmd2.Parameters.AddWithValue("TaskName", "bob") cmd2.ExecuteNonQuery() cn.Close() DataGridView1.DataSource = ds.Projects DataGridView2.DataSource = ds.Tasks End Sub Any thoughts would be greatly appreciated.

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  • ObjectDataSource Insert and Update methods error

    - by Jack
    I m developing asp.net 3.5 project. When I want to Insert with DetailsView this error occured: Error : ObjectDataSource 'ObjectDataSource2' could not find a non-generic method 'AddCity' that has parameters: CITY_NAME. <asp:ObjectDataSource ID="ObjectDataSource2" runat="server" SelectMethod="GetCityByID" UpdateMethod="UpdateCity" InsertMethod="AddCity" TypeName="NOP_CRM.Lib.nop_cities" OldValuesParameterFormatString="original_{0}"> <SelectParameters> <asp:ControlParameter ControlID="GridView1" Name="cityid" PropertyName="SelectedValue" Type="Int32" DefaultValue="1" /> </SelectParameters> <UpdateParameters> <asp:Parameter Name="CITY_NAME" Type="String" /> </UpdateParameters> <InsertParameters> <asp:Parameter Name="CITY_NAME" Type="String" /> </InsertParameters> </asp:ObjectDataSource> ... public int AddCity(string cityname) { CITY_NAME = cityname; Insert(); return _CITY_ID; }

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  • datalist itemdatabound event having issues changing item bg color on condition

    - by Jreeter
    Hey guys I'm trying to do something really simple.. I'm checking a data column in my datarow if it's 0 I want the item back color in the datalist to be green if its < 0 remain transparent... if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { DataRowView drv = (DataRowView)(e.Item.DataItem); int rating = int.Parse(drv.Row["rating"].ToString()); if (rating > 0) { e.Item.BackColor = System.Drawing.Color.Green; } } I've stepped through with debugger and it's hitting all the conditions the color just isn't changing.. I know it has to be something simple I just can't see it.

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  • ASP.Net Layered app - Share Entity Data Model amongst layers

    - by Chris Klepeis
    How can I share the auto-generated entity data model (generated object classes) amongst all layers of my C# web app whilst only granting query access in the data layer? This uses the typical 3 layer approach: data, business, presentation. My data layer returns an IEnumerable<T> to my business layer, but I cannot return type T to the presentation layer because I do not want the presentation layer to know of the existence of the data layer - which is where the entity framework auto-generated my classes. It was recommended to have a seperate layer with just the data model, but I'm unsure how to seperate the data model from the query functionality the entity framework provides.

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  • Getting table schema from a query

    - by Appu
    As per MSDN, SqlDataReader.GetSchemaTable returns column metadata for the query executed. I am wondering is there a similar method that will give table metadata for the given query? I mean what tables are involved and what aliases it has got. In my application, I get the query and I need to append the where clause programically. Using GetSchemaTable(), I can get the column metadata and the table it belongs to. But even though table has aliases, it still return the real table name. Is there a way to get the aliase name for that table? Following code shows getting the column metadata. const string connectionString = "your_connection_string"; string sql = "select c.id as s,c.firstname from contact as c"; using(SqlConnection connection = new SqlConnection(connectionString)) using(SqlCommand command = new SqlCommand(sql, connection)) { connection.Open(); SqlDataReader reader = command.ExecuteReader(CommandBehavior.KeyInfo); DataTable schema = reader.GetSchemaTable(); foreach (DataRow row in schema.Rows) { foreach (DataColumn column in schema.Columns) { Console.WriteLine(column.ColumnName + " = " + row[column]); } Console.WriteLine("----------------------------------------"); } Console.Read(); } This will give me details of columns correctly. But when I see BaseTableName for column Id, it is giving contact rather than the alias name c. Is there any way to get the table schema and aliases from a query like the above? Any help would be great!

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  • Can Entity Framework be used for the purpose of entity/schema definition at application runtime?

    - by Kabeer
    Hello. Can 'Entity Framework' be used for the purpose of entity definition at application runtime? Ok, to make it simple, here is what I want to achieve: My application is a product. I should be able to define entities at runtime on the basis of inputs gathered from an 'authoring' user (in effect this means 'model first' approach). These entities are of course persistable. Further, after having defined the entities and their relationships, I should be able to make complex queries across them for many reasons, including reports. Is the above possible and how? So far what I have realized is that there is a dependency on Visual Studio.

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  • why DataColumn AllowDbNull is true even if oracle db does not allow null

    - by matti
    Hi. I have column SomeId in table SomeLink. When I look with tOra or Sql Plus Worksheet both state: tOra: Column name Data type Default Null Comment SOMEID INTEGER {null} NOT NULL {null} Sql Plus: SOMEID NOT NULL NUMBER(38) I have authored a method that's intended to give default values to all NOT NULL fields that don't have values: public static void GetDefaultValuesForNonNullColumns(DataRow row) { foreach(DataColumn col in row.Table.Columns) { if (Convert.IsDBNull(row[col]) && !col.AllowDBNull) { if (ColumnIsNumeric(col.DataType)) row[col] = 0; else if (col.DataType == typeof(DateTime)) row[col] = DateTime.Now; else if (col.DataType == typeof(String)) row[col] = string.Empty; else if (col.DataType == typeof(Char)) row[col] = ' '; else throw new Exception(string.Format("Unsupported column type: {0}", col.DataType)); } } } When SOMEID is handled in loop the AllowDBNull = true. I really can't understand. The table is created in DataSet like this: _someLinkAdptr = _dbFactory.CreateDataAdapter(); _someLinkAdptr.SelectCommand = _dbFactory.CreateCommand(); _someLinkAdptr.SelectCommand.Connection = _cnctn; _someLinkAdptr.SelectCommand.CommandText = GetSomeLinkSelectTxtAndParams(_someLinkAdptr.SelectCommand, UndefinedValue.ToString(), UndefinedValue.ToString()); Select command returns no rows. The idea is that I can then use commandbuilder to get InsertCommand without building it myself. The row is added to dataset's table like this: private static void CreateDocLink(int anId, int anotherId) { DataRow row = _someDataSet.Tables["SomeLink"].NewRow(); row["AnId"] = anId; row["AnotherId"] = anotherId; Utility.GetDefaultValuesForNonNullColumns(row); _someDataSet.Tables["SomeLink"].Rows.Add(row); } When DataAdapter is updated to oracle db I get: ORA-01400: cannot insert NULL into (SOMESCHEMA.SOMELINK.SOMEID) Cheers & BR -Matti

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  • linq, selecting columns as IEnumerable<DataRow>

    - by joe
    how can i do in linq: IEnumerable<DataRow> query = from rec in dt.AsEnumerable() where rec.Field<decimal>("column2") == 1 && foo(rec.Field<decimal>("column1")) select new { column1 = rec.Field<decimal>("column1"), column2 = rec.Field<decimal>("column2"), column3 = rec.Field<decimal>("column3")} ; this does not work. Im trying to select some columns as new datatable then join it later with some other datatable.

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  • Can I use a class as an object in .NET to create instances of that class?

    - by Troy
    I'm writing a fairly uncomplicated program which can "connect" to several different types of data sources including text files and various databases. I've decided to implement each of these connection types as a class inherited from an interface I called iConnection. So, for example, I have TextConnection, MySQLConnection, &c... as classes. In another static class I've got a dictionary with human-readable names for these connections as keys. For the value of each dictionary entry, I want the class itself. That way, I can do things like: newConnection = new dict[connectionTypeString](); Is there a way to do something like this? I'm fairly new to C# so I'd appreciate any help.

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  • Importing an Excel WorkSheet into a Datatable

    - by Nick LaMarca
    I have been asked to create import functionality in my application. I am getting an excel worksheet as input. The worksheet has column headers followed by data. The users want to simply select an xls file from their system, click upload and the tool deletes the table in the database and adds this new data. I thought the best way would be too bring the data into a datatable object and do a foeach for every row in the datatable insert row by row into the db. My question is what can anyone give me code to open an excel file, know what line the data starts on in the file, and import the data into a datable object?

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  • How do I connect to SqlLite db file from c#?

    - by Nick
    Hey all... I am trying to connect to a sqllite db from with a c# application. I have never worked with SQLLite before. var connectionString = @"data source='C:\TestData\StressData.s3db'"; connection = new SQLiteConnection(connectionString); connection.Open(); When i attempt to open the connection I get the following exception: System.NotSupportedException: The given path's format is not supported. at System.Security.Util.StringExpressionSet.CanonicalizePath(String path, Boolean needFullPath) at System.Security.Util.StringExpressionSet.CreateListFromExpressions(String[] str, Boolean needFullPath) What am I doing wrong? Thanks.. Nick

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  • visusal studio embedded crystal report keeps prompting database login?

    - by phill
    I'm using visual studio 2005 to develop a form with a combobox passing a value into the parameter of an embedded crystal report. I'm trying to figure out why it keeps prompting me for a database login every single time you try to run the report with a different combobox selection. Here is my code: private Sub Form1_load... Dim ConnName As String Dim ServerName As String Dim DBName As String Dim user As String Dim pass As String Dim gDBA As ADODB.Connection Dim records As ADODB.Recordset Dim datver As ADODB.Recordset Dim query As String '---OPEN THE DATABASE CONNECTIONS gDBA = New ADODB.Connection ': gDBA.CursorLocation = adUseServer 'Added to prevent time out error gDBA.CommandTimeout = 1000 : gDBA.ConnectionTimeout = 1000 gDBA.ConnectionString = "Server=svr13;Database=subscribers;User ID=KViews;Password=Solution;Trusted_Connection=True;" gDBA.Open("Data Source=Kaseya;Initial Catalog=subscribers;User Id=KViews;Password=Solution;", "KViews", "Solution") records = New ADODB.Recordset query = "select distinct groupname from _v_k order by groupname desc" 'records.ActiveConnection = gDBA.ConnectionString records.CursorType = CursorTypeEnum.adOpenForwardOnly records.LockType = LockTypeEnum.adLockReadOnly records.Open(query, gDBA) Do While Not records.EOF ComboBox1.Items.Add(records.Fields("groupname").Value) records.MoveNext() Loop end Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim selected As String selected = ComboBox1.Text Dim cryRpt As New ReportDocument cryRpt.Load("C:\Visual Studio 2005\Projects\WindowsApplication1\WindowsApplication1\CrystalReport1.rpt") cryRpt.SetDatabaseLogon("KViews", "Solutions", "svr13", "subscribers") cryRpt.SetParameterValue("companyname", selected) CrystalReportViewer1.ReportSource = cryRpt CrystalReportViewer1.Refresh() End Sub I looked at this previous posting http://stackoverflow.com/questions/1132314/database-login-prompt-with-crystal-reports but this wasn't very helpful. I couldn't find where a CMC was to disable the prompt. Any ideas? thanks in advance

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