datareader

This is a commonly seen ADO.NET pattern to retrieve data from database using a data reader, but strangely doesn't work. Doesn't work: public static IEnumerable<IDataRecord> SelectDataRecord<T>(string query, string connString) where T : IDbConnection, new() { using (var conn = new T()) { using (var cmd = conn.CreateCommand()) { cmd.CommandText = query; cmd.Connection.ConnectionString = connString; cmd.Connection.Open(); using (var reader = (DbDataReader)cmd.ExecuteReader()) { // the main part while (reader.Read()) { yield return (IDataRecord)reader; } } } } This does work: public static

My goal is to retrieve data from a data source, add some metadata to it and insert it to another target. The target has schema with four more columns then the source (calculated columns). I am using SqlBulkCopy , which requires a reader with all columns (including the 4 calculated). Is there a way to add columns to the DataReader manually? or if it's not possible what alternatives i have for the data insertion? I needed to do this, and also have the ability to make columns based on other columns and have the column's value depend on the row index of the reader. This class implements

We are having some issues with our data layer when large datasets are returned from a SQL server query via a DataReader . As we use the DataReader to populate business objects and serialize them back to the client, the fetch can take several minutes (we are showing progress to the user :-)), but we've found that there's some pretty hard-core locking going on on the affected tables which is causing other updates to be blocked. So I guess my slightly naive question is, at what point are the locks which are taken out as a result of executing the query actually relinquished? We seem to be finding

How can I store the results of a DataReader into an array, but still be able to reference them by column name? I essentially want to be able to clone the DataReader's content so that I can close the reader and still have access. I don't want to store the items in a DataTable like everyone suggests. I've seen a lot of answers, but I couldn't really find any for what I wanted The easiest way I've found to do this is by populating the array with dictionaries with Strings as keys and Objects as values, like so: ' Read data from database Dim result As New ArrayList() Dr = myCommand.ExecuteReader()

I have this code: var query = "SELECT * FROM Cats"; var conn = new SqlConnection(sqlConnectionString); conn.Open(); var cmd = new SqlCommand(query); var reader = cmd.ExecuteReader(); while (reader.Read()) { var CatName = reader.GetString(0); var CatDOB = reader.GetDateTime(1); var CatStatus = reader.GetInt32(2); } I'd like to pull the rows out into an anonymous type collection, which I'd normally do using LINQ to iterate, but I an not sure if it's possible due to the way you have to call .Read() each time to get the next row. Is there a way to do this? You can create helper generic method and

Here is my sample code that I am using to fetch data from database: on DAO layer: public IEnumerable<IDataRecord> GetDATA(ICommonSearchCriteriaDto commonSearchCriteriaDto) { using(DbContext) { DbDataReader reader = DbContext.GetReader("ABC_PACKAGE.GET_DATA", oracleParams.ToArray(), CommandType.StoredProcedure); while (reader.Read()) { yield return reader; } } } On BO layer I am calling the above method like: List<IGridDataDto> GridDataDtos = MapMultiple(_costDriversGraphDao.GetGraphData(commonSearchCriteriaDto)).ToList(); on mapper layer MapMultiple method is defined like: public IGridDataDto

Here is my code, I close and open the reader and it's still not working. A few threads can access this function concurrently but there is a lock. It works a few times in the beginning but sooner or later I get the exception 'Invalid attempt to call Read when reader is closed' at private IList<BursaUser> GetUsers(SqlCommand cmd) { IList<User> users = new List<User>(); User user; lock (thisLock) { SqlDataReader dr = null; try { Conn.Open(); dr = cmd.ExecuteReader(CommandBehavior.CloseConnection); while (dr.Read()) { user = new User { UserId = Convert.ToInt32(dr["WorkerNum"]), CompanyName = dr[