Database Reference
In-Depth Information
DBMS
DB
Or Other
OLE DB
Data Source
ADO.NET Data Provider
ADO.NET Data Providers:
Connection
• OLE DB
• SQL Server Client
• Oracle Database Client
• Others . . .
Command
Data
Reader
Data
Adaptor
Dataset
XML
Document
Figure 11-17
Components of an aDO.NEt
Data Provider
Application
Application
The
ADO.NET DataSet
is a representation of the data stored in the computer memory as a
set of data separate from the one in the DBMS. The DataSet is distinct and disconnected from the
DBMS data. This allows commands to be run against the DataSet instead of the actual data. DataSet
data can be constructed from data in multiple databases, and they can be managed by different
DBMS products. The DataSet contains the DataTableCollection and the DataRelationCollection. A
more detailed version of the ADO.NET dataset object model is shown in Figure 11-19.
The
DataTableCollection
mimics DBMS tables with
DataTable objects
. DataTable
objects include a
DataColumnCollection
, a
DataRowCollection
, and
Constraints
. Data
values are stored in DataRow collections in three forms:
original values
,
current values
, and
Figure 11-18
the aDO.NEt Object
Model
ADO.NET
Data Providers
DataSet
Data Consumers
Connection
DataTableCollection
DataTable
Columns
Rows
Data Adapter
Constraints
DataRelationCollection
Relationships
Command
Data Reader
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