Active server page tutorial (ado.net)

1. Overview of ADO.NET
Architecture of ADO.NET
.NET Data Providers
Data Providers Components

2.  ADO.NET is a large set of .NET classes that
enable us to retrieve and manipulate data, and
update data.
 As an integral part of the .NET framework, it
shares many of its features:
 sources, in very many different ways.

3.  features such as multi-language support,
garbage collection, just-in-time compilation,
object-oriented design,
 and dynamic caching, and is far more than an
upgrade of previous versions of ADO.

4.  The ADO.NET object model consists of two
fundamental components: the Dataset, which
is disconnected from the data source and
doesn't need to know where the data it holds
came from; and the .NET
 data provider. The .NET data providers allow
us to connect to the data source, and to
execute SQL.

5.  At the time of writing, there are three .NET
data providers available: for SQL Server, for
OLE DB data sources.
 for ODBC-compliant data sources. Each
provider exists in a namespace within the
System. Data namespace, and
 consists of a number of classes.

6.  Each .NET data provider consists of four main
components:
 Connection – used to connect to the data
source
 Command– used to execute a command
against the data source and retrieve a Data
Reader.

7.  Dataset, or to execute an INSERT, UPDATE, or
DELETE command against the data source
 Data Reader– a forward-only, read-only
connected result set.
 Data Adapter – used to populate a Dataset
with data from the data source, and to update
the data source

9.  The connection classes are very similar to the
ADO Connection object, and like that, they are
used to
 represent a connection to a specific data source.
The connection classes store the information
that ADO.NET
 needs to connect to a data source in the form of
a familiar connection string (just as in ADO).

10.  The command classes expose the
IDbCommand interface and are similar to the
ADO Command object – they
 are used to execute SQL statements or stored
procedures in the data source. Also, like the
ADO Command
 object, the command classes have a Command
Text property, which contains the text of the
command to be

11.  executed against the data source, and a
Command Type property, which indicates
whether the command is a
 SQL statement, the name of a stored procedure,
or the name of a table.

13.  The DataReader is ADO.NET's answer to the
connected recordset in ADO. However, the
DataReader is
 forward-only and read-only – we can't navigate
through it at random, and we can't use it to
update the data source. It

14.  therefore allows extremely fast access to data
that we just want to iterate through once, and it
is recommended to use
 the Data Reader (rather than the DataSet)
wherever possible.

16.  The other major component of ADO.NET
is the DataSet; this corresponds very
roughly to the ADO
 recordset. It differs, however, in two
important respects. The first of these is
that the DataSet is always

17.  exactly the same way to manipulate data from
a traditional data source or from an XML
document. In order to
 connect a DataSet to a data source, we need to
use the DataAdapter as an intermediary
between the
 DataSet and the .NET data provider: