Understanding the Pervasive PSQL Database Management System

Pervasive PSQL is a comprehensive database management system built around Pervasive Software's MicroKernel Database Engine. Pervasive PSQL offers easy installation, uncomplicated maintenance, and high levels of performance and reliability.

This section explains the product and its components.

What is a Database?

Loosely defined, a database is simply a collection of data. Generally, the data is structured by dividing it into sub-sets of information that share the same characteristics. Some examples of a database are:

A telephone book

Each entry in the phone book consists of four characteristics: first name, last name, address, and phone number.

A collection of digital photographs

Each picture on your hard disk has two characteristics: a file name, and the data within the file that represents the image.

A list of orchards and the fruit grown by each

Each entry in the orchard list might consist of three characteristics: orchard name, address, and date founded. The related list of fruits might have five characteristics: orchard name, fruit name, fruit type (McIntosh, Fuji, and so on), fruit price, and a taste rating.

In the particular context of this product, a database is a specific, well-defined collection of related information. You can probably find one or more databases available on your computer or your network. For example, you may have a database of information related to vendors from whom you purchase supplies or raw materials, and you probably also have a database containing customer or member information. Each of these is a distinct, well-defined collection of related information.

What is a Database Management System?

As citizens of the computer age, we are surrounded by collections of information-databases-everywhere we go. Unfortunately, all this data is of no use to anyone without methods to sort it, search it, analyze it, and keep it current.

A database management system, or DBMS, is a computer program designed to manage large amounts of data and to allow other computer programs and people to interact with the data. A DBMS can also be referred to informally as a database engine or simply an engine. A DBMS performs the following tasks:

Controls access to the data. The DBMS can act as a watchdog to prevent the wrong people from using the data.

Structures the data so it can be interpreted by other applications. The DBMS ensures that all the data adheres to the database structure, so that other computer programs can work with the data using common methods.

Keeps the data safe and prevents it from getting garbled or lost. The DBMS facilitates backing up the data in case of catastrophic loss, and also accesses it in a consistent manner to prevent the data from suffering inadvertent damage.

Makes it easy to add new information, find it, update it, and delete it. The DBMS readily accepts new data and provides tools that you can use to locate, update, and remove information as you see fit. It verifies that the data inserted fits within defined attributes for the database fields.

Allows you to analyze relationships among different sets of data. The DBMS stores the data in a way that allows you to examine how any piece of data relates to any other piece of data.

In summary, the DBMS organizes your data, keeps it safe, and helps you to use it and understand it.

Components of Pervasive PSQL

The Pervasive PSQL DBMS consists of a variety of components designed to help you achieve your data management goals. For more detailed information about these components and how they interact, please see Pervasive Products and Services.

MicroKernel Database Engine

The MicroKernel Database Engine (MKDE) is the high-performance heart of Pervasive PSQL. The MKDE works directly with the data files on your computer's hard disk. When requested, it directly inserts new data, deletes unnecessary data, and ensures the safety and integrity of the data files at all times, even when people and applications are working with the data.

SQL Relational Database Engine

The SQL Relational Database Engine (SRDE) interacts with the MKDE and the client (described below). It provides many powerful features including support for Microsoft ODBC, sophisticated search and analysis capability, and security.

Client (also called Requester)

In client/server systems, the client resides on the computer workstation. The client interacts with the client application and across the network with both the MKDE and the SRDE on the server.

Pervasive PSQL Control Center

The Pervasive PSQL Control Center (PCC) is an easy-to-use, graphical tool designed to help you create and manipulate databases and control your DBMS. It allows you to access nearly all the functions of the product from one place. For a tour of PCC, see Chapter 3, Using Pervasive PSQL Control Center.

Utilities

A variety of graphical and command-line tools provide support for testing, configuring, and manipulating the many features and options provided by Pervasive PSQL. These tools are covered in-depth in Advanced Operations Guide, but a brief introduction to them is provided in Helpful Utilities .

Documentation

Pervasive PSQL comes with a complete set of softcopy documentation. For more information about the documentation, see Using Pervasive PSQL Documentation .