what is the main difference detween the dataset and datareader

i think
dataset is directly updated to the database
datareader is temporarly storage the data

Comparison of DataSet and DataReader objects (DataSet vs DataReader)

DataSet is a disconnected architecture, while DataReader has live connection while reading data. If we want to cache data and pass to a different tier DataSet forms the best choice and it has decent XML support.

When application needs to access data from more than one table DataSet forms the best choice.

If we need to move back while reading records, datareader does not support this functionality.

One of the biggest drawbacks of DataSet is speed. As DataSet carry considerable overhead because of relations, multiple tables etc speed is slower than DataReader. Always try to use DataReader wherever possible, as it’s meant specially for speed performance.

Datareader is forward and read only recordset in which the data manipulations are cant carried. but dataset is the miniature of database in which the datas can be accessed randomly and data manipulations can be carried

Data Reader is a forward only and read only data
DataSet is used to maintain relationships between multiple
tables.

Data Reader can't persist the data
Data Set can persist the data