1). What is the namespace in which .NET has the data functionality classes ?
Following are the namespaces provided by .NET for data management :-
1. System.data :
This contains the basic objects used for accessing and storing relational data, such as
DataSet,DataTable, and DataRelation. Each of these is independent of the type of data
source and the way we connect to it.
It contains the objects that we use to connect to a data source via an OLE-DB provider,
such as OleDbConnection, OleDbCommand, etc. These objects inherit from the common
base classes, and so have the same properties, methods, and events as the SqlClient
This contains the objects that we use to connect to a data source via the Tabular Data
Stream (TDS) interface of Microsoft SQL Server (only). This can generally provide better performance as it removes some of the intermediate layers required by an OLE-DB
This Contains the basic objects required to create, read, store, write, and manipulate
XML documents according to W3C recommendations.
2). Can you give a overview of ADO.NET architecture ?
The most important section in ADO.NET architecture is “Data Provider”. Data Provider
provides access to datasource (SQL SERVER, ACCESS, ORACLE).In short it provides
object to achieve functionalities like opening and closing connection, retrieve data and
update data. In the below figure you can see the four main sections of a data provider :-
2. Command object (This is the responsible object to use stored procedures)
3. Data Adapter (This object acts as a bridge between datastore and dataset).
4. Datareader (This object reads data from data store in forward only mode).
*** “DataView” object is used to sort and filter data in Datatable.
3). What are the two fundamental objects in ADO.NET ?
Datareader and Dataset
4). What is difference between dataset and datareader ?
DataReader provides forward-only and read-only access to data, while the
DataSet object can hold more than one table (in other words more than one
rowset) from the same data source as well as the relationships between them.
Dataset is a disconnected architecture while datareader is connected
Dataset can persist contents while datareader can not persist contents, they
are forward only.
5). What are major difference between classic ADO and ADO.NET ?
Following are some major differences between both
√ As in classic ADO we had client and server side cursors they are no more
present in ADO.NET. Note it's a disconnected model so they are no more
√ Locking is not supported due to disconnected model.
√ All data persist in XML as compared to classic ADO where data
persisted in Binary format also
6). What is the use of connection object ?
They are used to connect a data to a Command object.
√ An OleDbConnection object is used with an OLE-DB provider255
√ A SqlConnection object uses Tabular Data Services (TDS) with MS SQL Server
7). What is the use of command objects ?
They are used to connect connection object to Datareader or dataset. Following are the
methods provided by command object :-
√ ExecuteNonQuery :- Executes the command defined in the CommandText
property against the connection defined in the Connection property for a query
that does not return any row (an UPDATE, DELETE or INSERT). Returns
an Integer indicating the number of rows affected by the query.
√ ExecuteReader :- Executes the command defined in the CommandText property
against the connection defined in the Connection property. Returns a "reader"
object that is connected to the resulting rowset within the database, allowing
the rows to be retrieved.
√ ExecuteScalar :- Executes the command defined in the CommandText property
against the connection defined in the Connection property. Returns only
single value (effectively the first column of the first row of the resulting rowset)
any other returned columns and rows are discarded. It is fast and efficient
when only a "singleton" value is required
8). What is the use of dataadapter ?
These are objects that connect one or more Command objects to a Dataset object. They
provide logic that would get data from the data store and populates the tables in the
DataSet, or pushes the changes in the DataSet back into the data store.
√ An OleDbDataAdapter object is used with an OLE-DB provider
√ A SqlDataAdapter object uses Tabular Data Services with MS SQL Server.