Data Adapters provide in teraction between DataBase and 
Dataset.It provite the functionalities like reading the 
data from database,update the data,filter the data and wite 
the data to Database

The data adapter we can use with data set.we can use data 
adapter when the data is in disconnected form & we have to 
apply some oprations on it.the data adapter is in the 
tabular form & we can create any no of virtual tables to 
fetch data.

DataAdapters is important object of Ado.net. it is used to 
transfer data to and from database.
DataAdapter is used to Interact with dataset.
DataAdapter has two method fill() and update().

DataAdapter acts like a mediator between Dataset and 
Datastore(ie.Oracle,Sqlserver or Access).It has two methods 
fill() and update().
For Ex:
SqlConnection con=new SqlConnection
("DataSource="databaseEngineName";Initial 
Catalog="DataBaseName";User 
Id="userName";Password="password";);
DataAdapter da=new DataAdapter(sqlcommand,con);
DataSet ds=new DataSet();
da.fill(ds,"tablename");
da.update(ds);

DataAdapter acts like a mediator between Dataset and 
Datastore
data adpters and datasets are disconnected model
through which we can store data on the local site and we 
can perform menupulation on that

DataAdapter is the bridge between the dataset and database.

Dataset is the Disconnected architecture,through 
dataadapter we can get the data from database to dataset.
Once we get the data from database, connection will be 
automatically disconnected.Just like Our mobile set.
Once we connected the charger to our mobile,the mobile will 
charged.After batary will charge we will disconnect from 
the adapter..like that.

Data Adapter is interface between database and dataset
whatever data is update that is handle by Data Adapter.