dataset

问题 The amount of coding that goes into the making of a DataSet is often significant. Now I'm not sure what the industry standard or best practise when dealing with data requests from multiple ASP.NET pages. Should I use a cache/session to pass on the DataSet from page to page or should I fetch directly from the database for each page? What's the most common approach here? 回答1: Here are my thoughts: It depends on the database and the type of data that you're trying to get, as well as what may

问题 I have a dataset set up with 3 fields, ID username and password. I want the user to type in a new username and passoword and this then gets saved back to the dataset. How do I take what has been typed in and save it into the data set? So far this is the code I have usersTableAdapters.UsersTableAdapter user = new usersTableAdapters.UsersTableAdapter(); user.usersDataTable usertable = user.GetData(); This allows me to connect to the data set although I am not sure how to take the values the

问题 Below is a snippet of the code. As you can see, that method returns a table from SQLite database, and adds that table to a DataSet if it doesn't exist yet. SQLiteConnection connection; DataSet Set = new DataSet(); DataTable GetTable(string tableName, string command) { if (!Set.Tables.Contains(tableName)) { var adapter = new SQLiteDataAdapter(command, connection); SQLiteCommandBuilder builder = new SQLiteCommandBuilder(adapter); adapter.FillSchema(Set, SchemaType.Source, tableName); adapter

问题 I use a created query to return a row of values from a key, I have checked on the query executor but when running the program it is returning null. Please help me I'm starting to lose my mind. I've tried debugging but the problem is coming from the fill data query and it is returning null. // Add ref. to the Dataset ViewMedia viewMediaSetInstance = new ViewMedia(); // Create an empty Table ViewMedia.ViewMediaDataTable viewMediaTable = new ViewMedia.ViewMediaDataTable(); // Create the Adapter

问题 I was reading this msdn article today and I am curious about finally part with disposing datatable. Is that really necessary? why should we dispose a datatable? If I exit the function or sub, is it not releasing the resources? Explanation in the article is; Dispose of the temporary data tables to release the resources. Private Sub UpdateDB() Dim deletedChildRecords As NorthwindDataSet.OrdersDataTable = _ CType(NorthwindDataSet.Orders.GetChanges(Data.DataRowState.Deleted), NorthwindDataSet

问题 I did some data processing using Flink (1.7.1 with Hadoop). At the end I'd like to write the dataset consisting of 2-tuples into a file. Currently, I am doing it like this: <Tuple2<Integer, Point>> pointsClustered = points.getClusteredPoints(...); pointsClustered.writeAsCsv(params.get("output"), "\n", ","); However, I would like to have the CSV headers written into the first line. The Flink's Javadoc API doesn't state any options for this. Furthermore, I couldn't find any solution googling

问题 I am comparing two datatables using the answer in this link Compare two Datatables but when I use the DataRelation function I am getting an error that both columns length should match. but I want to only compare specific columns. Currently I have it this way: // Using a Dataset to make use of a DataRelation Object using (DataSet ds = new DataSet()) { //Add Tables ds.Tables.AddRange(new DataTable[] { dt.Copy(), dataTable.Copy() }); //Get First Columns for DataRelation DataColumn[] firstcolumns

问题 I had a Dataset with some data in it. When I tried to write this DataSet into a file, everything was OK. But When I tried to write it into a MemoryStream, the XML file declaration was lost. The code looks like: DataSet dSet = new DataSet(); //load schema, fill data in dSet.WriteXML("testFile.xml"); MemoryStream stream = new MemoryStream(); dSet.WriteXML(stream); stream.Seek(0,SeekOrigin.Begin); When I opened file testFile.xml, I got: <?xml version="1.0" standalone="yes"?> //balabala But When

问题 I need some raw data to visualize it with google charts and some other APIs. Problem is that i some raw data that includes timestamps too. For example visitors visiting a website i.e. from which device (mobile/computer etc) they accessed website, at what time (hours:minutes:second:miliseconds) and what which links they visited etc. Please help me to know if someone knows about such kind of dummy raw data on web. 回答1: You can build your own dataset using Google Spreadsheets. For example,

问题 I was trying to store the url on button click using the following code.There were no error but the required url is not sroeing in my column field (i used ntext data tpe for this).Please help me if there was some mistake in my code public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } public void Storetxt(String txt) { //connection to the database string connection = "Data Source=.\\sqlexpress2005;Initial Catalog=PtsKuratlas;Integrated