Chapter 3 windows database applications

Giáo Viên: Nguyễn Văn Thắng.3- 3 OLEDB UDA concept to data from any source using the same programming tools Visual Basic and Database Applications ADO.NET set of objects to refer to data

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Chapter 3

Windows Database

Applications

Advanced Programming

Using Visual Basic.NET

Universal Data Access

(UDA)

multiple providers

application on any type of computer

Visual Basic and Database Applications

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Giáo Viên: Nguyễn Văn Thắng.

3- 3

OLEDB

UDA concept

to data from any source using the same

programming tools

ADO.NET

set of objects to refer to data from any

source

with common data representation (data

types) from multiple sources

ActiveX Data Objects à ADO

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ADO.NET

(Extensible Markup Language)

datasets provide for

– Flexibility à adapt to changes in data or

presentation tier

– Scalability à handle increases in the number

of users and servers

XML is an industry standard

format for storing and transferring data over multiple platforms.

ADO.NET Components

• Data Providers – manipulate the data using

SQL statements or stored procedures

– SQLClient à for SQL Server

– OleDbClient à for all other database formats

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ADO.NET Components

• DataSet Objects à holds a copy of the

data in memory

from many sources

DataSet objects the same

DataTable objects

A Sample DataTable

one entity

of data à field

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3- 9

DataTable Characteristics

fields) uniquely identifies each record

tables

using a foreign key

The DataSet Object Model

DataSet

DataTable Collection DataTable

DataRowCollection DataColumnCollection ParentRelations ChildRelations ConstraintCollection DataView

DataRelationCollection

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Data Provider Objects

• Connection object – link to a data source

• DataAdapter object – handles retrieving

and updating data in a DataSet object

• Command object – storeprocedure and

executes SQL statements

• DataReader object –

for read-only access

A NET data provider is a set

of components designed for fast access and manipulation of data.

A NET data provider is a set

of components designed for fast access and manipulation of data.

Use the DataSet object

connection

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.NET Data Provider Objects

SelectCommand InsertCommand UpdateCommand DeleteCommand

Connection

.NET Data Provider

Command

Data Adapter

DataReader

XML Data

tags

format for storing and transferring data.

<au_id>172-32-1176</au_id>

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XML Schema File

constraints

in the Solution Explorer

XML Data Format

Advantages

handling of data

executes faster

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Microsoft Database Files

databases

version of SQL Server

MSDE and SQL Server

Obtaining Data

data source

and updating the data

bind controls to the fields in the DataSet

object

MSDE and SQL Server

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Obtaining Data

MSDE and SQL Server

Connection Data Adapter

Data

Web Form

Windows Form

Use Server Explorer to select and drag fields to the form

Connection and adapter components are automatically added to the component tray.

Use Server Explorer to select and drag fields to the form

Connection and adapter components are automatically added to the component tray.

Display the DataSet in the

DataGrid

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Populating Combo Boxes

with Data

property

– Connects to the dataset

property

– Connects to the field

name

load the list

Displaying Data in Individual Fields

daEmployee.Fill(DsEmployee1)

Sorting Data for the ListBox

– Virtual view of an

existing table

from the Data section of

the toolbox

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Creating a Parameterized

Query

statement to specify the criteria

SELECT emp_id, fname, minit, lname, job_id, job_lvl, hire_date FROM employee

WHERE lname = @lname

SELECT emp_id, fname, minit, lname, job_id, job_lvl, hire_date FROM employee

WHERE lname = @lname

Using the Query Builder

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Binding Individual Controls

to Data Fields

Adding an Expression to the

DataSet Schema

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Using the ValueMember

Property of Combo Boxes

field to display in the list

unique field value

parameter

daEmployee.SelectCommand.Parameters(“@emp_id”).Value =

cboNames.SelectedValue.ToString

daEmployee.SelectCommand.Parameters(“@emp_id”).Value =

cboNames.SelectedValue.ToString

Multiple Tier Projects

interface

User Interface

(Form)

DataSet Connection DataAdapter

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Binding to Combo Boxes

the data view

properties from fields in the data view

Multiple Tiers

DataBindings for Multiple

Tiers (phần này sinh viên tự

tham khảo trong sách)

DataBindings.Add method

another event procedure

Multiple Tiers

ControlName.DataBindings.Add(“text”, DataSource, “FieldName”)

lblEmployeeID.DataBindings.Add(“text”, dsEmployee.Tables(“employee”), “emp_id”)

lblHireDate.DataBindings.Add(“text”, dsEmployee.Tables(0), “hire_date”)

lblEmployeeID.DataBindings.Add(“text”, dsEmployee.Tables(“employee”), “emp_id”)

lblHireDate.DataBindings.Add(“text”, dsEmployee.Tables(0), “hire_date”)

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