what is the difference between data adapter and data reader?

Question

What is the difference between data adapter and data reader?

Answer 1

Please see DataReader, DataAdapter & DataSet - When to use? :

ADO.NET provides two central Data Access Components. The excellent thing is that, they are common across all Databases, be it SQL Server or other competitive databases. Its only the namespace to be used, that differs, while using a Database other than SQL Server.

Answer 2

A DataReader is an object returned from the ExecuteReader method of a DbCommand object. It is a forward-only cursor over the rows in the each result set. Using a DataReader, you can access each column of the result set, read all rows of the set, and advance to the next result set if there are more than one.

A DataAdapter is an object that contains four DbCommand objects: one each for SELECT, INSERT, DELETE and UPDATE commands. It mediates between these commands and a DataSet though the Fill and Update methods.

Answer 3

Data reader is an object through which you can read a sequential stream of data. it's a forward only data wherein you cannot go back to read previous data. data set and data adapter object help us to work in disconnected mode. data set is an in cache memory representation of tables. the data is filled from the data source to the data set thro' the data adapter. once the table in the dataset is modified, the changes are broadcast to the database back thro; the data adapter.