ODBC, OLE DB, and ADOIntroduction

Dr. Ron Eaglin

Data Access Standards

• The reasons for ODBC, OLE DB, and ADO are to provide a standardized method and API for accessing and manipulating Data from different databases.

• ODBC (Open Database Connectivity) – is the most basic and common standard interface for accessing databases.

ODBC Conformance Levels

• Application Programming Interface– Core– Level 1– Level 2

• SQL Grammar– Minimum– Core– Extended

Establishing an ODBC Datasource

• In Control Panel, Administrative Options, there is an icon for ODBC Datasources

ODBC Datasources

ODBC Datasources

• File Data Source – A physical file which can be shared among users on a single computer.

• System Data Source – A source of data that is local to a single computer. Can be remotely accessed through the computer.

• User Data Source – Available only to the user who created it.

System DSN

System DSN

System DSN

System DSN

System DSN

Microsoft OLE DB

• Creates an Object Oriented Programming model on top of ODB (and other drivers) to allow a programmatic access to database through a Object Oriented interface.

Using Microsoft OLE DB

Client Application

Code

ODBC Data

Sources

MDB Files

SQL Server

ADO

OLE DBConsumer

OLEDB

MSDASQL.DLL

SQLOLEDB.DLL

MSJTOR35.DLL

OLE DBProviders

Db Client Application

that uses OLE DB

ADO and ADO.Net

• One level of abstraction higher that OLE DB.

• Basic object model that overlies the more complex OLE DB model.

Basic Definition

• Namespace – In programming a namespace encapsulates other name spaces, programming classes, and other functions that are common and uniquely named.

ADO.Net Namespaces

• The ADO.NET Object Model– Objects of System.Data– .NET data providers

• ADO.NET namespace hierarchy– Organizes the object model– Includes:

• System.Data • System.Data.OleDb• System.Data.Common• System.Data.SqlClient• System.Data.SqlTypes

The System.Data Namespace

System.Data

.OleDb.SqlClient

OleDbCommandOleDbConnectionOleDbDataReaderOleDbDataAdapter

SqlCommandSqlConnectionSqlDataReader

SqlDataAdapter

.Common Contains classes shared by both

System.Data Classes

System.Data

DataTable - In-memory cache of a database table

DataRow - Used to manipulate a row in a DataTable

DataRelation - Used to relate 2 DataTables to each other

DataColumn - Used to define the columns in a DataTable

DataViewManager - Used to create views on DataSets

DataSet - In-memory cache of data

Using ADO.Net Classes

• Connection Object– ODBCConnection– OleDBConnection– SQLConnection

• ConnectionString property – defines the information to allow connecting to a database.

Connection Class

// create a connection string

String conStr="Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=NWIND_RW.MDB";

// create a connection object using the connection string

OleDbConnection aConn = new OleDbConnection(conStr);

// open the connection

aConn.Open();

// Perform database actions

aConn.Close();