datareader

问题 Hii Guys !!! I made one C# class and one handler in Asp.net..In My C# file I made a function which is as Below: public MySqlDataReader Consulta(String sql){ String error=""; try { string connectionString = "Server=*****;Port=3306;Database=db;UID=*****;Pwd=****;pooling=false"; MySqlConnection conn; conn = new MySqlConnection(connectionString); conn.Open(); //string s = "select empid,empname,authcode from authcode"; MySqlCommand cmd = new MySqlCommand(sql,conn); //cmd.CommandText = s; cmd

问题 Hii Guys !!! I made one C# class and one handler in Asp.net..In My C# file I made a function which is as Below: public MySqlDataReader Consulta(String sql){ String error=""; try { string connectionString = "Server=*****;Port=3306;Database=db;UID=*****;Pwd=****;pooling=false"; MySqlConnection conn; conn = new MySqlConnection(connectionString); conn.Open(); //string s = "select empid,empname,authcode from authcode"; MySqlCommand cmd = new MySqlCommand(sql,conn); //cmd.CommandText = s; cmd

问题 I need to iterate twice through a DataReader. Is there a way to do this without using DataSets and without running the query twice? I'm using C#, by the way. Thanks 回答1: The short answer is no, you run through the enumeration for the result sets and then you're done. What should probably be done is to dump the results to some kind of simplified raw results that you can iterate over as much as you want (avoiding the overhead of the DataSet). If you take a peek at MSDN, it notes that the

问题 I have a class like below, class Student { public string Name {get; set;} public string Surname {get; set;} public int Age {get; set;} public string Address {get; set;} } And I have a MySql table with 50,000 records. The Structure of the table is like below, ID NAME SURNAME AGE ADDRESS 1 Joe Philip 20 Moscow 2 Misha Johny 25 London ... And I have a C# code, List<Student> students = new List<Student>(); string sql = "SELECT name,surname,age,address FROM Students"; command.CommandText = sql;

问题 I am looking to develop a website for a news channel . So, Obviously its gonna receive a lot of hits daily and will be updated a lot on daily basis.. I have experience in ASP.Net and SQL Server.. These are the technologies i am considering to work with. Please help me choose the right method considering the amount of load it will take.. Technology?? 1) ASP.Net Webforms 2) ASP.Net MVC 1.0 And data access?? 1) Linq to SQL (Impressive but rumours say Microsoft is abandoning it) 2) Linq to

问题 This is the code I' using for reading data from sql through DataReader. It gives Error when there is a NULL in table. How to handle it? I tried c.ActualWeight= dr[0] as float? ?? default(float); The problem with this is that it is successful in Handling NULLs but the result is Always 0 even if the sql database has value 1 in that field. { List<Inventory_Connector> LC = new List<Inventory_Connector>(); string ConString = "data source=DELL\\SQLSERVER1;Initial Catalog=Camo;Integrated Security

问题 I have the following code and i want to loop through all the fields in the result of this query and populate the dictionary called field. Given a datareader is this possible? OracleCommand command = connection.CreateCommand(); string sql = "Select * from MYTABLE where ID = " + id; command.CommandText = sql; Dictionary<string, string> fields = new Dictionary<string, string>(); OracleDataReader reader = command.ExecuteReader(); 回答1: You should be able to do something like this: Dictionary

问题 I have a basic sql statement that looks up a user and returns one record but when I run a block of code that says if(myReader.Read()) it returns false. I have stepped through the code and examined the reader object and it does in fact contain one record. below is the code. sql: SELECT user_name, user_password, user_state FROM users WHERE users.user_id = 123 System.Data.Common.DbCommand _cmd = this.GetCommand(conn, _dbf, sqlText, CommandType.Text); System.Data.Common.DbConnection _cn = _cmd

问题 In the "each", when run the "FirstOrDefault" will error "There is already an open DataReader associated with this Connection which must be closed first.". How to do ? public int SetUser(string[] dIds, string pId) { using (var scope = _dbContextScopeFactory.Create()) { var db = scope.DbContexts.Get<JuCheapContext>(); var users = db.Users; var user = users.FirstOrDefault(m => m.Id == pId); if (user.Places == null) { user.Places = new List<PlaceEntity>(); } var place = db.Place.Include(m => m

问题 I am cleaning up the DataReaders in an old .NET 1.1 project that I inherited. The previous developer coded the data-access-layer in such a way that most of the DAL methods returned SqlDataReaders (thus leaving it up to the caller to properly call the .Close() or .Dispose() methods). I have come across a situation, though, where a caller is not catching the returned SqlDataReader (and therefore is not disposing of it properly). See the code below: Data Access Method: Public Shared Function