What is the difference between data reader and data adapter

1. DateReader is an forward only and read only cursor type if you are accessing data through DataRead it shows the data on the web form/control but you can not perform the paging feature on that record(because it's forward only type). Reader is best fit to show the Data (where no need to work on data). DataAdapter is not only connect with the Databse(through Command object) it provide four types of command (InsertCommand, UpdateCommand, DeleteCommand, SelectCommand), It supports to the disconnected Architecture of .NET show we can populate the records to the DataSet. where as Dataadapter is best fit to work on data.


2. Datareader is connection oriented it moves in the forward direction only it keeps single row at a time.Dataadapter acts as a bridge between datasource and dataset and it is a multipurpose object ie we can insert update delete throught dataadapter


3. The DataSet consists of a collection of DataTable objects that you can relate to each other with DataRelation objects. A DataSet can read and write data and schema as XML documents..The DataReader object is the ADO.NET counterpart of the read-only forward-only default ADO cursor

4. Data Reader take the data sequentially from the command object and requies the connection should be open while it is getting data.Data Adapter fetch all the required data from database and pass it to DataSet.DataSet get all the required data from Data Adapter. DataSet contains data in the form of Data Table.

5.
DataSet is a disconnected Articeture... means,

It is followed by Dataset. In this once the data has been read by Dataset from SqlDataAdapter we can close the connection to database and retirve the data from Dataset where ever we want. Dataset hold the data in the form of table and do not interact with Datasouse.

DataReader : it is a Connected Articeture... means,

that while SqlDataReader reads the data from database and also reading data from SqlDataReader to any variable the connection to database should be open. Also once you read some data from SqlDataReader you should save them becouse it is not possible to go back and read it again.