Do you know that? 24% - I began freelancing after geing downsized next

Explain the use of data adapter.

The data adapter objects connect a command objects to a Dataset object. 
They provide the means for the exchange of data between the data store and the tables in the DataSet.

An OleDbDataAdapter object is used with an OLE-DB provider
A SqlDataAdapter object uses Tabular Data Services with MS SQL Server.