InterBase 4

Borland InterBase 4

Table of Contents, InterBase

Introduction
Versioning Engine
Active Database
Integrity Constraints
Triggers
Stored Procedures
Event Alerters
Distributed Database
International Features
Ease of Use
InterBase on Intel

Introduction

Borland InterBase is one of the leading database server products in today's mission-critical applications marketplace. InterBase mission-critical applications include a large number of embedded systems--both VAR and corporate--in which applications are developed using InterBase as the core database management system within a specific application. Major corporate applications also utilize InterBase for their mission-critical applications which require an extremely robust system that must absolutely remain highly available. These applications may include large financial organizations, process control, telecommunications, financial trading, network management, scientific engineering, and emergency response applications. Some key InterBase customers include: Motorola, Dow Jones/Telerate, Abbott Laboratories, American Airlines, Boston Stock Exchange, MAXM, Philadelphia Stock Exchange, Ameritech/NOTIS, Westinghouse, and the U.S. Army.

Versioning Engine

InterBase supports a unique versioning engine which ensures high data availability for both transaction processing users and decision support users. Traditional database servers support the On-Line Transaction Processing (OLTP) model of database interaction, characterized by a high volume of short, simple transactions. While InterBase's versioning engine supports these short OLTP-style transactions, it is also equipped to concurrently handle long-duration, decision support-type transactions within a single server, and with high availability for all users.

The versioning engine allows for read transactions to never require a lock on the records being used and are contention-free--meaning that readers never block writers in the transaction system. Unlike other systems on the market, the read transactions in InterBase require no additional programming. InterBase gives a time-consistent, repeatable result for every query. The InterBase versioning engine allows long- and short-duration transactions to coexist and maximizes the throughput of all transactions.

Active Database

InterBase supports a number of advanced database features including triggers, server-based event-alerters, and user-defined functions to enable key business rules and functionality from directly within the database server. The benefit to having these features is that many of the commonly used data rules can now be off-loaded from the client application to the server. This results in a more efficient client application, centralized code maintenance and higher performance.

Integrity Constraints

Declarative integrity constraints efficiently and reliably maintain the integrity of data on the server and are easy for the user to prescribe. There are four categories of constraints:

Unique and Primary Key: This constraint ensures that no two rows in a table have the same values for the set of key columns.
Referential: This constraint ensures that parent-child relationships between tables are valid; that is, a set of columns in a foreign key have the same values as the primary key columns of the referenced table.
Check Constraint: This constraint states that the associated search condition will be valid for every row in the table.
Domain: Allows for the creation of new subtypes and column level integrity specification. Domains can be used to specify a range of acceptable values for a column or enumerate a list of valid values as well as default values.

InterBase 4 syntax for integrity constraints is fully compatible with the ANSI SQL92 standard. In addition, the user can specify arbitrarily complex integrity constraints.

Triggers

Combined with stored procedures, InterBase supports a powerful implementation of triggers. A trigger is a self-contained set of statements which is automatically executed whenever a row in a table is inserted, updated, or deleted. In response to a triggering condition (for example, after update), the statements associated with the trigger body are executed. The trigger body could contain one or more Execute Procedure statements. The InterBase trigger syntax supports the use of New and Old context variables which makes before and after column values for a row available. This can be used to write a trigger that, for example, ensures that no employee has a negative salary. InterBase also supports the notion of a trigger class, which is used to determine the order in which triggers are executed. This feature is useful in cases where a certain action satisfies the trigger condition of more than one trigger, and execution order is important.

Stored Procedures

A stored procedure is a set of statements stored in the database, rather than embedded in each application. Stored procedures can be executed using the execute procedure statement by specifying the procedure name and a list of parameters, if any. A variety of statement types are allowed in a stored procedure, including SQL, control flow, and declaration statements. Stored procedures offer the following advantages:

Performance: Stored procedures can lead to dramatic performance improvements by off-loading commonly used business rules to the server.
Code Sharing: A common piece of code, once written and stored in the database, can be used by any application that connects to the database.
Reliability: Code sharing leads to modular design, making the job of maintenance easier. Because the code is centrally defined once, and used by all the applications, the chance of data becoming corrupted by misbehaved applications is minimized.

The InterBase 4 stored procedure syntax follows the proposed ANSI/ISO SQL3 standard. This includes support for begin..end, if..then..else, while, for, when, and declare statements as well as SQL statements: select, insert, update, and delete. Exceptions, which are user-defined error conditions, can be defined and raised inside stored procedures. Exceptions and standard error conditions can be trapped using the when statement which then executes the statement body associated with it. Stored procedures can be nested; that is, a stored procedure may be called from inside another stored procedure. InterBase stored procedures may also be recursive. This is a particularly useful feature for component processing, such as bill-of-materials.

Event Alerters

InterBase's trigger syntax can also be used to post an alert, which in turn posts an event to the InterBase event manager with a particular event name. Event Alerters enable the database to function as an active database which automatically notifies interested processes when a change of interest takes place. For example, when a quantity-on-hand field in an inventory table goes below a certain quantity, a trigger can cause an E-mail message to be sent to the purchasing manager. Event Alerters save development time and provide for a more efficient application design.

Distributed Database

InterBase offers the capability to perform a distributed automatic 2-phase commit (2PC). It enables users to automatically achieve a high degree of reliability in a distributed database environment and offers the required transparency that users expect from an industrial-strength database. This important feature takes the traditional 2-phase commit process one step further. InterBase is the first database product to provide distributed recovery from a 2-phase commit. This ensures full recovery without a single point of failure, because the status of the commit is distributed among all the servers.

International Features

InterBase allows a number of international character sets for data storage and manipulation. Both 8-bit and 16-bit character sets are supported for all string and BLOb operations. A default character set and collation order can be specified for the database as a whole. These can be overridden for a particular column of a given table. Collation can also be specified with the Order By clause in Select statements. String literals with a character set name prefix can be used to specify international character data. The benefit of the new InterBase 4 international features is that it is easy to implement international language set applications for worldwide deployment.

Ease of Use

InterBase offers high-end database functions and installs in minutes. It has a smaller footprint compared to competitive products and requires far less disk space, making it attractive for corporate customers, VARs, and ISVs for developing and deploying mission-critical applications. InterBase is a low-maintenance database. Its self-tuning features offer the most optimal performance, eliminating the need for a professional DBA at each user site where the database is deployed. InterBase offers on-line backups and immediate recovery after failure for customers with high-reliability requirements.

Competitive products are more complex, require advanced system administrative skills to install, need large amounts of disk and memory space, and are difficult to maintain.

InterBase on Intel

Novell's NetWare is an important new platform for InterBase 4. InterBase 4 runs as a Novell NetWare Loadable Module (NLM). All client applications talk to a single NLM on a NetWare server, which coordinates database access and facilitates sharing of database buffers. InterBase makes efficient use of the Novell file system and takes advantage of NetWare features to deliver superior performance for both transaction processing and desktop applications. Both IPX and TCP/IP protocols are supported for communications.

Additional Intel-based platforms for InterBase include: Microsoft NT and IBM OS/2 (r).

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