The DataSet is an in-memory database – a collection of virtual tables with means to populate, examine, modify and deleting delete the tables and the data within them. You can also define and manipulate the relationships between the tables and tables, create and enforce constraints to maintain those relationships. Surprisingly, the data that populates the tables within a DataSet can and frequently does come from different data sources, leading to very powerful flexibility in connecting and maintaining data in various server sources.

The primary purpose of a DataSet is to allow the user to operate on data from a server in a disconnected mode. The temporary separation of data from the server is a desirable thing because it frees memory on the server, as well as connection and network resources. The DataSet allows data to be ‘borrowed’ from the server in relatively small usable chunks. The DataSet then ‘manages’ the connection between the data and allows the user to edit, update, delete, append, or select portions of that data.
The DataSet is first and foremost a collection of table objects. These table objects can be imported from various and diverse data sources such as SQL Server, Oracle, XML files, and the like, or they can be entered programmatically or through a convenient User Interface (UI) and then added to the DataSet programmatically. The most useful methods are to Accept Changes, AcceptChanges, RejectChanges, Merge, Clone, a few functions for reading and writing XML and XML schema, and – most important of all- the GetChanges method, which gets a DataSet which contains all of the data changes made to the current one since it was loaded.
The table objects look like tables in a regular database, though they are virtual tables, which reside only in memory. The table objects have collections of DataColumns, DataRows, Constraints, DataRelations, Property Collections, DataRowView, and a PrimaryKey, which may be a collection of DataColumns.
DataTable Class Members
Constructors
Visibility
Constructor
Parameters
 
 
 
public
DataTable
( )
 
 
 
public
DataTable
( String tableName )
 
 
 

Properties
Visibility
Name
Value Type
Accessibility
 
 
 
 
public
CaseSensitive
Boolean
[ Get , Set ]
 
 
 
 
public
ChildRelations
DataRelationCollection
[ Get ]
 
 
 
 
public
Columns
DataColumnCollection
[ Get ]
 
 
 
 
public
Constraints
ConstraintCollection
[ Get ]
 
 
 
 
public
Container
IContainer
[ Get ]
 
 
 
 
public
DataSet
DataSet
[ Get ]
 
 
 
 
public
DefaultView
DataView
[ Get ]
 
 
 
 
public
DesignMode
Boolean
[ Get ]
 
 
 
 
public
DisplayExpression
String
[ Get , Set ]
 
 
 
 
public
ExtendedProperties
PropertyCollection
[ Get ]
 
 
 
 
public
HasErrors
Boolean
[ Get ]
 
 
 
 
public
Locale
CultureInfo
[ Get , Set ]
 
 
 
 
public
MinimumCapacity
Int32
[ Get , Set ]
 
 
 
 
public
Namespace
String
[ Get , Set ]
 
 
 
 
public
ParentRelations
DataRelationCollection
[ Get ]
 
 
 
 
public
Prefix
String
[ Get , Set ]
 
 
 
 
public
PrimaryKey
DataColumn
[ Get , Set ]
 
 
 
 
public
Rows
DataRowCollection
[ Get ]
 
 
 
 
public
Site
ISite
[ Get , Set ]
 
 
 
 
public
TableName
String
[ Get , Set ]
 
 
 
 

Methods
Visibility
Name
Parameters
Return Type
 
 
 
 
public
AcceptChanges
( )
Void
 
 
 
 
public
BeginInit
( )
Void
 
 
 
 
public
BeginLoadData
( )
Void
 
 
 
 
public
Clear
( )
Void
 
 
 
 
public
Clone
( )
DataTable
 
 
 
 
public
Compute
( String expression , String filter )
Object
 
 
 
 
public
Copy
( )
DataTable
 
 
 
 
public
EndInit
( )
Void
 
 
 
 
public
EndLoadData
( )
Void
 
 
 
 
public
GetChanges
( DataRowState rowStates )
DataTable
 
 
 
 
public
GetChanges
( )
DataTable
 
 
 
 
public
GetErrors
( )
DataRow
 
 
 
 
public
ImportRow
( DataRow row )
Void
 
 
 
 
public
LoadDataRow
( Object values , Boolean fAcceptChanges )
DataRow
 
 
 
 
public
NewRow
( )
DataRow
 
 
 
 
public
RejectChanges
( )
Void
 
 
 
 
public
Reset
( )
Void
 
 
 
 
public
Select
( String filterExpression , String sort , DataViewRowState recordStates )
DataRow
 
 
 
 
public
Select
( String filterExpression )
DataRow
 
 
 
 
public
Select
( )
DataRow
 
 
 
 
public
Select
( String filterExpression , String sort )
DataRow
 
 
 
 
public
ToString
( )
String
 
 
 
 

Events
Multicast
Name
Type
 
 
 
multicast
ColumnChanged
DataColumnChangeEventHandler
 
 
 
multicast
ColumnChanging
DataColumnChangeEventHandler
 
 
 
multicast
Disposed
EventHandler
 
 
 
multicast
RowChanged
DataRowChangeEventHandler
 
 
 
multicast
RowChanging
DataRowChangeEventHandler
 
 
 
multicast
RowDeleted
DataRowChangeEventHandler
 
 
 
multicast
RowDeleting
DataRowChangeEventHandler


Rows are added programmatically using the DataRows object:
 
Dim dr as DataRow=tblEmployee.NewRow()
dr(“dcFirstName”)=”Elmer”
dr(“dcLastName”)=”Fudd”
tblEmployee.Rows.Add(dr)
 
 
Resources
Tutorial: ADO.NET Populate a DataSet from a Database
This tutorial discusses populating a DataSet from a Database.
Tutorial: DataSet Vs. DataReader
This is an interesting resource that discusses DataSet and Datareader.