Diverse Access developers specialise in the Design, Development and Configuration of the following databases:

1. 1. MySQL Server
   2. SQL Server 2000
   3. Access Server

Databases Overview

Databases come in all different shapes and sizes. They can be flat files of ASCII data (like Q&A) or complex binary tree structures (Oracle or Sybase). In any form, a database is a data store, or a place that holds data.

If a database is simply a collection of data, then what keeps track of changes to this data?

That is the job of the database management system, or DBMS. Some DBMSs are relational. Those are RDBMS. The relational part refers to the fact that separate collections of data within the reaches of the RDBMS can be looked at together in unison. The RDBMS is responsible for ensuring the integrity of the database. Sometimes, things will get out of whack and the RDBMS will keep all that data in line.

Database Terminology

In the days of yours, programming database applications are pretty simple. There were mainframe databases and there were very few microcomputer databases available. The ones that were available cost an arm and a leg. The cheap ones were, well, you got what you paid for. But you always had database files, records, and fields. The database terms of yesteryear, however, have been replaced by new ones. Some of the bigger database companies like Oracle and Sybase have redefined database terminology. The main thrust of this redefining is most likely in response to the larger customer base that is not "programming-literate."

A programmer can deal with files, records and fields. But more and more non-technical people are creating database applications and queries these days. Their formal training is through the use of applications. As you'll see, some of the new terms are commonly found in spreadsheet and word processing programs.

The following is a list of current database terms that will be used in the rest of this chapter and throughout the book:

• ClientServer. Clientserver is more of an architecture than a tangible entity. The client is a computer system that requests the services provided by an entirely different computer system. On a smaller scale, the client and server may be separate processes running on the same computer system. The distinction is that there is a service provider (the server), and a consumer of that service (the client). For your purposes here, the server would be the RDBMS, and the client is your application that is requesting data from the server.
• Database or Instance. The database or instance is the entity, or collection of data, that is created and stored for retrieval and modification. Depending on the RDBMS, several of these entities can exist on a single machine. For instance, multiple Oracle instances can exist on a UNIX server. Each has a distinct area for data, and unless properly configured, they have no knowledge of each other. A database or instance is comprised of schemas.
• Schema. A schema is a collection of database objects that belongs to a single user of the database. Databases have many users.
• Table. A table is a database object that contains a single set of data. Like things are stored in tables. For instance, at a company a normal table to have is an employee table. This would store all kinds of information about an employee. A table contains rows of data.
• Row. A row of data is a single record in a table. A row is divided into columns.
• Column. A column is the smallest unit of data in a table. It is a part of the row. When data is displayed in a spreadsheet-like fashion, a column would be the up/down slice of data.

MySQL

MySQL is the world's most popular Open Source Database, designed for speed, power and precision in mission critical, heavy load use. MySQL AB is the company owned by the MySQL founders.

The MySQL database server embodies an ingenious software architecture that maximises speed and customisability. Extensive reuse of pieces of code within the software and an ambition to produce minimalistic but functionally rich features have resulted in a database management system unmatched in speed, compactness, stability and ease of deployment. The unique separation of the core server from the table handler makes it possible to run MySQL under strict transaction control or with ultrafast transactionless disk access, whichever is most appropriate for the situation.

Today MySQL is the most popular open source database server in the world with more than 3 million installations powering websites, datawarehouses, business applications, logging systems and more. Customers such as Yahoo! Finance, MP3.com, Motorola, NASA, Silicon Graphics, and Texas Instruments use the MySQL server in mission-critical applications.

SQL Server 2000

SQL Server 2000 exceeds dependability requirements and provides innovative capabilities that increase employee effectiveness, integrate heterogeneous IT ecosystems, and maximize capital and operating budgets. SQL Server 2000 provides the enterprise data management platform your organization needs to adapt quickly in a fast-changing environment.

With the lowest implementation and maintenance costs in the industry, SQL Server 2000 delivers rapid return on your data management investment. SQL Server 2000 supports the rapid development of enterprise-class business applications that can give your company a critical competitive advantage.

Benchmarked for scalability, speed, and performance, SQL Server 2000 is a fully enterprise-class database product, providing core support for Extensible Markup Language (XML) and Internet queries.