Chapter 7 Create, Add, Delete, and Edit Data in a Disconnected Environment

Chapter 7
Create, Add, Delete, and Edit Data
in a Disconnected Environment
Objectives in chapter

Create a DataSet graphically.

Create a DataSet programmatically.

Add a DataTable to a DataSet.

Add a relationship between tables within a DataSet.

Navigate a relationship between tables.

Merge DataSet contents.

Copy DataSet contents.

Create a typed DataSet.

Create DataTables.

Manage data within a DataTable.

Create and use DataViews.

Represent data in a DataSet by using XML. (NO)

Use the OleDbDataAdapter object to access an ADO Recordset or Record.


Generate DataAdapter commands automatically by using the Command-Builder
object.
Before we go…

Con.connectionString=“….”;

/// con.Open(); -> do not need

cmd.Connectiion=con;

cmd.CommandType="Select ", conSinhVien)

cmd.CommandText=“Select * from …”;

DataAdapter da=new DataAdapter();

Da.SelectCommand=cmd;

Dataset Ds=new Dataset();

Da.Fill(Ds);

DataGrid1.DataSource=ds.tables[0];
Chapter content
 Lesson 1:Creating DataSet Objects
 Lesson 2: Creating DataTable Objects.
 Lesson 3: Creating DataAdapter Objects
 Lesson 4: Working with Data in
DataTable Objects
 Lesson 6: Creating and Using DataView

Objects
Lesson 1:
Creating
DataSet
Objects
 DataSet Objects
 Creating DataSet Objects
Programmatically
Lesson 1:
Creating
DataSet
Objects
 DataSet Objects

temporarily store the data

Like array, in memory
Dataset structure
Objective: Using in-memory database

DataSet Structure

DataTable Structure
DataColumn
DataRow

Build manual dataset

DataView


Example
Why DataSet?

Perform database modifications

always
disconnected

To transfer data between tiers have .NET framework
(Linux, Unix, Windows…)

To send between computers across network by HTTP
protocol in XML format

To manipulate the data without an open connection

To relate data from multiple sources

To bind data to a Windows form

Power data structure
 Event an application without database, we can using dataset
… instead of arraylist, array…
Populating DataSets
 Manual
 From existing databae, using
DataAdapter
 Read from XML data files
 Build from XSD files
 But before filling dataset…

… we need to know dataset structure
DataSet Components
 DataTable
 DataColumn
 DataRow
 Constraint
 DataRelation
 DataView
DataSet Object Model
DataSet
DataTable Collection
DataTable
DataRowCollection
DataColumnCollection
ParentRelations
ChildRelations
ConstraintCollection
DataView
DataRelationCollection
See next page
1.reside in the
System.Data
namespace
2.doesn’t care
where it came
from
Lesson 6Lesson 4
DataSet class tree model
Constraint
Constraint

s
s
Constraint
Constraint
Columns
Columns
Column
Column
DataSet
DataSet
Tables
Tables
Table
Table
Object
Collection
Relations
Relations
Relation
Relation
Rows
Rows
Row
Row
DataTable
DataSet
DataTable
DataRow
DataColumn
DataTable

DataRow
DataColumn

Represents one table in DataSet

Are accessed using the DataSet's
Tables property
 Collection of DataTables
 Using index : ds.tables(0)
 Using name: ds.tables(“authors”)

Each DataTable has:
 A Columns property
 (Add,remove,removeat,Item)
 A Rows property
 (Add,remove,removeat,Item)

Access to data-cell
 Table.Rows(index).Item(index)
Dim DT1 As New DataTable("TableName")
DataTable Core Pro./Methods

TableName property

A PrimaryKey property
 array of datacolumn

Select(filter): datarow()
 End of sql


NewRow

DefaultView

Example: Create table and dataset
Ds=new DataSet();
ds.DataSetName = "BookAuthors";
Tauthors =new DataTable("Author");
Ds.Tables.add (Authors);
DataTable Accessing example
myDataTable.Rows(5)
returns a DataRow object that is the 6
th
row of
myDataTable
myDataRow(2)
returns an object representing the data stored in the
3rd column of myDataRow
myDataTable.Rows(5)(2)
returns an object representing the data stored in the
3rd column of the 6
th
row of the myDataTable
DataColumn Class

Describes one column of data in a
DataTable

DataColumn objects describe
table's schema


DataAdapters can generate the
required DataColumns

Similar to column in datatable

Doesn’t have Value property

Core Pro. / methods

ColumnName

DataType

Ex. Gettype(integer)

AllowDBNull

AutoIncrement

DefaultValue

Unique

ReadOnly
DataSet
DataTable
DataRow
DataColumn
DataTable

DataRow
DataColumn
Example
DataColumn Cid =
authors.Columns.Add("ID",gettype(integer));
Cid.AutoIncrement = true;
DataColumn Cname =
authors.Columns.Add("Name", gettype(String));
authors.PrimaryKey = new DataColumn[] {Cid};
DataRow Class

A DataRow object provides access
to one row of data in a DataTable

A DataTable's DataRow objects
contain all the data in the
DataTable

Create

Table.NewRow method

Can access DataRow values by
providing:

Column name

Column number

DataColumn object


Core Pro./methods

Item(index) : get cell value

IsNull

Delete
DataSet
DataTable
DataRow
DataColumn
DataTable
DataRow
DataColumn
Populating DataSet-Manual
1.
Construct your own DataSet (schema)
1.
Create Dataset
2.
Add DataTable(s)
3.
Add DataColumn(s) to DataTable
4.
Define datatable schema
2.
Fill Data into DataTable(s) in DataSet
1.
Add DataRow to DataTable

2.
Processing data in dataset …
Dim ds As New DataSet , r As DataRow
With ds.Tables.Add("SV")
.Columns.Add("id")
.Columns.Add("Name")
End With
With ds.Tables("SV")
r = .NewRow()
r("id") = "aa"
r("name") = "bb"
.Rows.Add(r)
End With
DataView

An custom view of a DataTable

Sorting, filtering, searching, editing, and
navigating the data from a DataSet

Using same data memory from Datatable

Each DataTable have DefaultView
DataView1 DataView2
SV1 Nguyen thi A
SV2 Nguyen thi C
SV3 Nguyen thi B
DataTable
row1
row2

row3
row2
row3
row1
row1
row3
row2
Dataview

Changes DataView affect DataTable automatically

We can get Dataview direct from DataTable:
DataTable1.DefaultView , but only 1 view

Using DataView, we can have multiple view
d1 =New DataView(ds.Tables[0]);
d1.Sort = "Last name“;
d2 =New DataView(ds.Tables[0]);
d2.Sort = "first name“;
DataGrid2.DataSource = d1;
DataGrid3.DataSource = d2;
Lesson 1:
Creating
DataSet
Objects

two kinds : typed, and untyped.

Un-Typed Dataset: from generic type


Typed Dataset:from schema (.xsd)
 DataSet Objects: 2 ways to creata

Declare a new DataSet object
programmatically for untype Dataset

Use design-time tools: for typed-Dataset
Lesson 1:
Creating
DataSet
Objects
 DataSet Objects:

Choosing typed or Un-typed Dataset?
 Demo1: Creating a typed DataSet with
the DataSet Designer
Lesson 1:
Creating
DataSet
Objects
 Demo2: Creating a Typed DataSet with
the Data Source Configuration Wizard
 Questions?
Lesson 1:
Creating
DataSet
Objects
 Exercise 3: Configuring Untyped
DataSet Objects
 Questions?