|Lesson 4||ODBC and middleware solutions |
|Objective ||Recognize ODBC, ADO, and other database access solutions. |
ODBC MiddleWare Solutions
The course project, VirtualBookshelf.com, requires your application to access a Microsoft Access database.
You might be asking yourself the question,
"How does the Web application access the database?"
Visual Studio is a powerful development tool and makes it easy for you to interface
the application with a database or databases.
Visual Studio is so good at interfacing the application to the database that it hides much of the work from you.
This might leave you wondering what it is actually doing.
To best understand what Visual Studio can do, you need to know a little about the technologies it uses.
For example, Middleware is a set of technologies generally known as Microsoft Data Access Components, that enables communication between your Web application and the database/s it communicates with.
These include the following high-level views:
- Web application: A collection of pages that comprise a Web site.
- interface: Provides access to an application, objects, hardware, etc.
- middleware: Software layer that enables communication between the application and the database.
Active Data Objects
ActiveX Data Objects (ADO) is a collection of objects used at the application level.
These objects allow your Web application to connect to databases, execute commands, and interface to the data. ADO is efficient and easy to use.
Open Database Connectivity (ODBC) is a standard protocol for accessing relational databases.
Application programmers use ODBC to pass Structured Query Language (SQL) queries to relational databases.
Companies developing database systems develop ODBC drivers specific to their database system. The ODBC driver provides a standard programming interface. As a result, applications such as the VirtualBookShelf project can access databases from different database system developers using the same programming interface.
OLE Data Base
Object Linking and Embedding (OLE) is a technology for developing reusable objects. OLE DB (Data Base) is a collection of objects that allow OLE applications to access sets of data as objects.
OLE DB consists of data providers
, such as a database, which contain the data and make it available to data consumers
, such as ADO. OLE DB can be used for both relational and non-relational data sources.
There are other data access solutions
available if your needs include data remoting
or if you are also writing traditional applications in Visual Basic or other languages.
This refers to storing data on a remote server. The data is accessed across a network. The remote data server could be in the same room or building as the client or even in a different country.
In the next lesson, the Structured Query Language will be discussed.