activex data objects in asp

7/29/2019 ActiveX Data Objects in ASP

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ASP-ADO


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ActiveX Data Objects (ADO)

Does for Microsoft data sources what ODBC did for

databases

similar in concept to the combination JDBC and JNDI (and then

some)

The process of using ADO involves the four step process:

Connect to the database

Define the data you want

Manipulate the data

Display the data


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ADO Software Architecture

VC++ VB Script Java

ADO

OLE DB

RDBMS E-mail Directory Services


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ADO, ODBC and OLE DB

ADO is the strategic way for using ODBC data sources on the

Windows platform

ODBC was the MS way of connecting to and using databases on the

Windows platform.

OLE DB extends ODBC by using the concept of service providers to

add the ability to connect to other non-database data sources (MS

Active Directory (LDAP), e-mail servers (Exchange))

ODBC Data Sources; provider = MSDASQL

MS Index Server; provider = MSIDXS

MS Active Directory Server - provider = ADSD300Object

MS Jet databases - provider = Microsoft.Jet.OLEDB.3.51

MS SQL Server - provider = SQLOLEDB

Oracle Databases - provider = MSDAORA


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Providers and Drivers

ADO

JET SQL Oracle

JET SQL Oracle

ODBC

Access SQL Oracle Access SQL Oracle

OLE DB

Providers

ODBC

Drivers


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Accessing a Database in ASP

The common way to access a database from inside

an ASP page is to:

Create an ADO connection to a database Open the database connection

Create an ADO recordset

Open the recordset

Extract the data you need from the recordset

Close the recordset

Close the connection


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DSN-less Database Connection


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Without DSN - OLE DB


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File DSN

------------- file.dsn -------

[ODBC]

DRIVER=Microsoft Access Driver (*.mdb)

ReadOnly=0UserCommitSync=Yes

Threads=3

SafeTransactions=0

PageTimeout=5

MaxScanRows=8

MaxBufferSize=512

ImplicitCommitSync=Yes

FIL=MS Access

DriverId=25


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Using File DSN


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ODBC Database Connection

With an ODBC connection, you can

connect to any database, on any computer inyour network, as long as an ODBC

connection is available.


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An ODBC Connection to an MS

Access Database

To create a connection to a MS Access Database:

Open the ODBC icon in your Control Panel.

Choose the System DSN tab. Click on Add in the System DSN tab.

Select the Microsoft Access Driver. ClickFinish.

In the next screen, clickSelect to locate the database.

Give the database a Data Source Name (DSN).

ClickOK.


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ADO Connection Object

The ADO Connection object is used to

create an open connection to a data source.

Through this connection, you can access

and manipulate a database.


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Connection Object

Collections


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Connection Object - Methods


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Connection Object - Properties


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Creating a ConnectionObject

Connection objects are created using the

CreateObject() function.

The only parameter is a string indicating the object tocreate

object_library_name.object

Dim cn

Set cn = Server.CreateObject(ADODB.Connection)


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ConnectionString

Once the ConnectionObject is created we need to give it a

ConnectionString to logon to the datasource

ConnectionString specifies the : provider

datasource name

userid (optional)

password (optional)

Dim cnn

Dim str str = Provider=MSDASQL; Data Source=mydatasource; User

Id=;Password=

cnn.ConnectionString = str


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Open() and Close()

Once the connection has been established the Connection must be

opened before using it

Likewise it should be closed when done.

Dim cnn

Dim str

Set cnn = CreateObject(ADODB.Connection)

str = Provider=MSDASQL.1,Data Source=mydatasource;

str = str & User TD=myuserid;Password=mypasscnn.ConnectionString = str

cnn.Open

..

cnn.Close


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Recordset

Record set objects are the recipients of the result of a SQL query

create the Connection object the create a recordset object and associate

them

Dim cnn

Dim rs

set cnn = CreateObject(ADODB.Connection)

set rs = CreateObject(ADODB.Recordset)

associate the record set with the connection

rs.ActiveConnection = cnn


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To use the Recordset, Open it

from previous code...

Dim SQL

SQL = SELECT..FROM..

rs.Open SQL

you can abbreviate this by doing the association at the same time as the Open

rs.Open SQL, cnn

this will eliminate the need for the rs.ActiveConnection = cnn statement


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Getting the data out

The record set is a collection of rows, each row containing the data in

the order that it was asked for in the SQL statement, each column in

the row can be accessed by its column name

for: SELECT CourseName from CourseTable

Dim string

While Not rs.EOF

string = string & rs(CourseName) &
rs.MoveNext

Wend


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Getting data in

To get data into an ADO data source use the ADO command object.

Use this for the SQL

insert

update

and delete statements

Dim SQL

Dim Cmd

Set cmd = CreateObject(ADODB.Command) create a command objectSQL = INSERT into ..

cmd.CommandText = SQL set the CommandTexy property of the CommandObject

cmd.ActiveConnection = cnn

cmd.Execute


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Display records from a database in an HTML Page


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Put the data in a table with colors and titles


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Another example, make data on page sortable by user

Company

Contact Name


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Using the Recordset Object

This example returns the value of the first column in the first two records:

ALFKI

ANTON

This example returns the value of the first three columns in the first record:

ALFKI

Alfreds FutterkisteMaria Anders


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ADO.NET

Under .NET, ADO hasnt changed much but the way you use it has

VB has changed extensively under .NET so we wont address its use with

VB (developer community isnt real happy about this)

the ADO API is pretty consistent across the MS supported .NETlanguages

Consists of the namespaces and classes that manage accessing backend

databases.

five namespaces

the most common are: Ststem.Data

System.Data.OleDB

System.Data.SqlClient

hundreds of classes


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the .NET Data Provider

DataReader

SelectCommand UpdateCommand

InmsertCommand DeleteCommand

Transaction Parameters

Connection Command

DB

.NET Data Provider


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.NET DataSet

ConstraintCollection

DataColumnCollection

DataRowCollection

DataTableDataTable

DataTableCollection

DataSet

DataRelationshipCollection


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System.Data Namespace

Consists mainly of classes that make up

ADO.NET

Allows a developer to build components

that manage data from data sources


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System.Data.OleDb Namespace

Ole DB .Net Data Provider

Designed to be a replacement for ODBC

Used for accessing different kinds of data

stores uniformly

non-relational databases

Dbase, Foxpro, Access

Spreadsheets


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System.Data.SqlClient Namespace

.NET data provider for MS SQL Server

classes bypass OLE DB to interact directly

with SQL Server

increase performance for SQL Server access


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MySql.Data.MySqlClient

namespace containing classes for accessing

MySQL databases

provided by MySQL organization


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IBM.Data.DB2 namespace

namespace for using IBM DB2 databases

with .NET

Provided by IBM with the DB2 product


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Oracle.DataAccess.Client

namespace used for accessing Oracle

databases from .NET

provided by Oracle with Oracle product

activex data objects in asp

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