Datasheet

❑ System.Data.SqlClient, which provides the objects used to communicate with SQL Server.
For some of the objects there are two copies – one in the
OleDb namespace, and one in the SqlClient
namespace. For example, there are two Connection objects – OleDbConnection and SqlConnection.
Having two objects means they can be optimized for particular databases. Look at figure 8-18 to see how
they relate to each other:
Figure 8-18
On the left we have the database and the connection, in the middle we have four
Command objects, and
on the right a
DataAdapter and a DataSet. Notice that the DataAdapter contains four Command
objects:
❑
SelectCommand, which fetches data.
❑
UpdateCommand, which updates data.
❑
InsertCommand, which inserts new data.
❑
DeleteCommand, which deletes data.
Command
Connection
CommandText
CommandType
Command
Connection
CommandText
CommandType
Command
Connection
CommandText
CommandType
Command
Connection
CommandText
CommandType
DataAdapter
SelectCommand
UpdateCommand
InsertCommand
DeleteCommand
DataSet
Connection
ConnectionString
Database
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Reading From Databases
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