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What is datareader in VBNET?
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Which one of the following properties of a DataReader indicates that it is open?
The property that indicates a DataReader is open is the IsClosed property. If IsClosed returns false, it means the DataReader is currently open and can be used to read data. Conversely, if IsClosed returns true, the DataReader is closed and cannot be used to retrieve data.
What is the difference between Datareader and dataset?
The Recordset was not XML-based and could not be serialized to XML easily or flexibly. Finally, a Recordset was not independent of a data store because it tracked a Connection object and through its methods could send queries to the data source to populate, update, and refresh its data. To that end, the Recordset contained functionality found in the ADO.NET DataSet, data reader, and data adapter objects. Similar to the DataSet, a Recordset could be disconnected from its data store and therefore act as an in-memory cache of data. Of course, it could also be used in a connected model depending on the cursor options that were set. Although the Recordset object stored multiple versions of each column for each of its rows, it was not by nature able to represent multiple tables without the use of the Data Shape Provider.
What is the diffrece between disconnected and connected environment?
Connected environment is one in which a user is required to be constantlyconnected to the Data Source while performing any operation in-order to keep the data up-to-date, whereas in Disconnected environment no constant connection to the Data Source is required.Moreover in connected environment the data concurrency effects can beeasily resolved but Connected environment causes network traffic. But in Disconnected environment since the user is not directly connected to the data source, the user can connect to the data source as and when required and hence it allows for Multiple applications to simultaneously interact with the Data Source. It also improves the scalability and performance of the applications.Few more differences can be contributed as the Connected Environment uses Datareader while the Disconnected one uses Dataset. This results in the fact that Connected Environment is Slower in speed in comparison to Disconnected environment for DML Operations. But as far the Connected Environment is concerned we get updated data and less chances of Dirty read, whereas Disconnected environment suffers from the major problem of Dirty read.Thanks & Regards,Shoaib R Khan - SRK
Difference between ado and ado.net?
ADO is a com base library that supports only connected data. This means that when we access the data (view, edit and update) it is affected in real-time,since the connection is being used all the time. ADO uses the objects as reference data known as Recordset object. Hence it basically gives a single table view of the data. We can also join tables to create a new set of records in ADO.ADO allows to create only client-side cursors. Using ADO we can persist records in XML format and XML integration is not possible.ADO.NET is a CLR based library that supports disconnected recordsets. This means that When we access data, ADO.NET makes a copy of the data using XML and holds the connection to pull down the data or to make any requested updates as long as we need. The best method to follow is ADO.NET.ADO.NET uses various objects known as Dataset that allow to access data in various methods. Hence it allows to store the relational model of the database and helps us to access /update the data in each related table individually. ADO.NET supports both client-side and server-side cursors. Also the cursors are handled as classes in ADO.NET providing a way to create efficient applications. Using ADO.NET we can manupulate records in XML format. Also ADO.NET 2.0 provides Multiple Active ResultSets (MARS) which allows to have two datareader on one connection open at sametime.
