TweetFollow Us on Twitter

dtF/SQL

Volume Number: 14 (1998)
Issue Number: 4
Column Tag: Tools Of The Trade

dtF/SQL -- The Little Engine That Could

by William A. Gilbert, Ph.D.

sLab makes there powerful SQL database engine available for anyone to use, at little or no cost

Introduction

File formats, saving data, relating fields, multiple files versus single file, backward compatibility... this is the struggle of all programmers with each new project. One could always use a third party database product such as FileMaker Pro or 4D but that only increases the complexity of development, deployment, and support. Another alternative is to use a centralized database system such as Sybase, Oracle, or Microsoft SQL Server, but often these solutions go beyond the scope of the project and introduce even more complexity and support problems.

Often what is needed is a small library which can store data, allow for the addition of new data definitions while being able to provide reasonable backward compatibility and to allow data protection from your competition. Yet at the same time it must allow access by those very special people -- the clients and customers!

Enter dtF/SQL, the little relational database engine that not only could but does achieve these goals and many others. dtF/SQL, a relational database engine for Mac OS, Windows 95/NT, and several Unix platforms from sLAB http://www.slab.com/, is provided as a small (403 Kbytes) linkable library which provides pure performance and pure pleasure for any developer who requires data storage in a file.

Having worked extensively with large scale SQL databases I had always wanted a product such as dtF/SQL for the "little" projects. With this library linked directly into my application, I can store both data and program parameters, access that data using simple or complex queries, and extend the data format by either adding additional fields to an existing table or by creating new tables. Using Finder file type and creator signature tags I can create double-clickable documents which launch the appropriate application under the Finder, as well as create custom icons for these documents. And the best part... it's free to non-commercial users and has reasonable licensing for commercial use. This is explained comprehensively at their web site.

dtF/SQL implements an impressive set of ANSI SQL functionality. It also supports the BLOB data type which is an arbitrarily large binary stream of data such as an image or a numeric array of data values. Both local and remote retrieval is fast. This subjective statement is based on experience with other database engines as well as experience with reading and parsing other file formats.

Hiding Complexity

Our goal as programmers is to provide our clients and customers with a product which performs both to specifications and expectations, but is also easy to use. Grady Booch has put it well: "The task of the software development team is to engineer the illusion of simplicity." This statement is particularly true for Macintosh applications, where end users have come to expect an environment in which one copies the application with some documents from the distribution disk and just expects to double-click a document and go. Using the dtF/SQL engine there are no extensions to load and configure, there is no restarting the computer, and there is no performance overhead imposed by switching processes or drivers. Additionally, there is no middleware to install with additional royalties. The bottom line is that the developer is able to deploy self-contained double-clickable database applications and documents, runnable even directly from a CD-ROM.

One Programmer's experience

I found the dtF/SQL API definitions and documentation, provided in PDF format, to be very readable. There are over 400 pages which describe the installation, data types, high level API, and low level API. Each API has a usage example as well as any restriction or limitation of the API.

The Macintosh distribution comes with the application, dtF/Admin, which allows one to create and experiment with a database to see the effects of SQL queries. This tool is a great way for beginners to learn how to create database schema or test SQL queries on real data before committing these queries to source code. If you mess up the database, just throw it in the trash and start over; you won't have an enraged database administrator breathing down your cubicle. The dtF/Admin application allows you to save scripts so that the database can be recreated and repopulated in seconds.

Of course, this can be done under program control as well. I keep my database schema scripts as STR# resources, then, with a New command, a new database can be created anytime.

At first I was disappointed that I couldn't write the equivalent of Sybase stored procedures to facilitate queries. I then realized that I was equally well off not being able to write and invoke stored procedures, because I was able to implement these procedures as C or C++ routines. I found that where I had become accustomed to writing complex SQL select statements with extensive join clauses, I could, with dtF/SQL, create a couple of separate workspaces, then use nested for loops to perform the same queries in a faster, much more logical fashion.

For those of you not familiar with SQL, the implications of this are significant. The SQL join command to resolve relationships takes lots of memory. In contrast, successive select statements which use the results of one SQL statement as input to the next SQL select statement takes almost no memory at all and with dtF/SQL is probably faster than doing the original join. The bottom line here is that one does not have to become an SQL guru to use dtF/SQL effectively. Arguably, such expertise may even work against you. The web-based, downloadable distribution comes with several complete, non-trivial example programs which demonstrate the usage of almost all of the APIs.

If Only...

dtF/SQL's implementation departs from the Macintosh application & document paradigm in one respect. In release 1.6 the database is actually two files, a database file and a separate file used to store BLOB data. This can present some challenges to the double-clickable document interface. The application must determine the location of the other file and then open it. For situations where a BLOB file is not required, an empty BLOB file can be created on the fly and opened, then deleted when the database session is over. If a BLOB file is required, one can use a Windows and Unix trick and require that the data file and BLOB file have the same name but require that the BLOB file end with the word "BLOB". Not truly the Macintosh way of doing things, but it works well enough.

The requirement of a separate BLOB file will be removed in release 1.8 which is expect to be available in early 1998. Then BLOB data will stored with all other data in the single file.

Availability

The dtF/SQL object library is available for Macintosh System 7.x and Mac OS 8 (68K and native PowerPC). MPW C/C++ , Symantec C/C++ and CodeWarrior C/C++ are supported. Separate versions for HyperCard, SuperCard, AppleScript, MacHTTP CGI, Smalltalk Agents and other environments are available. dtF/SQL also is an integral component of the Internet-enabled client/server development system from Pictorius, Inc. and the Oberon/F-based client/server system from microsystems. The dtF/SQL engine is also available for DOS, Win16, Win32, NT, OS/2, SUN OS, HP/UX and Linux. You must purchase support separately. It is provided by e-mail and is timely and informative.

The documentation is supplied as PDF files which can be read with Adobe Acrobat. I would have preferred hard copy, especially for the API definitions when first learning the library. On the other hand, these APIs are few and are learned quickly. The code examples are excellent and non-trivial. There also are some third party examples which range from to obvious to obfuscated.

The CodeWarrior CD-ROM distribution contains a demo version of this product, dtF Lite, as well as some experimental PowerPlant classes which encapsulate the dtF/SQL API. The standalone database tool, dtF/Admin, also is provided and is very useful of anyone who wants to learn more about relational databases and the SQL syntax in general

The database and BLOB files are binary compatible between Macintosh, PC, and Unix platforms, making the dtF/SQL engine and database files a perfect candidate for distribution on CD-ROM.

There are ODBC drivers for dtF/SQL for Win16 and Win32; Macintosh ODBC drivers will be ported shortly. Support for Java JDBC is under development and should be part of the upcoming version 1.7 release.

Scalability

Once you have deployed your application, your users may come back and ask about scaling up so that the members of their organizations can use your application to examine and modify shared data. Does this mean that you will have scrap your work and learn to use Sybase, Oracle, or ODBC libraries? No! dtF/SQL is available in a client/server configuration; so, as a developer, you add a few lines of connection code and relink your existing source with the dtF client library. Your customer purchases and runs the dtF/SQL server for their database files (licensed separately from sLAB, downloaded from the web with a password). They can now use your newly relinked application, with its familiar UI, to access and share their data. The dtF/SQL LAN server runs on Macintosh, Windows 95/NT, and some Unix platforms. Version 1.7 will allow any dtF/SQL client to connect to any dtF/SQL server.

Recommendation

I can unconditionally recommend the dtF library to any programmer who wants to develop and deploy solutions which deliver performance and simplicity to the customer. As for robustness, let me add in conclusion that I have crashed about a thousand times during development and have never had a dtF/SQL database file become corrupt as a result.

Pricing

All single user non-commercial dtF/SQL products are free and can be downloaded from the web, including documentation. There are no restrictions such as time-outs or maximum record sizes with the downloaded product. Non-commercial uses of the engine are also free. Distribution of commercial products are priced on a unit basis. Large volume pricing can bring the price down to 1 DM (about $0.65 US) per unit. For server pricing contact sLAB directly by e-mail or phone, available from their web site.

Useful URL's

http://www.slab.de/uk/homepage/index.html is sLab's home page, in English. All dtF products, commercial and non-commercial, are available from this site.


Editor's Note

sLab has made an astonishing offer to the programming community at large - a free, high end SQL relational database for non-commercial use. After I read this review, I trotted over to their home page and downloaded all the stuff I needed to look at this product. As Dr. Gilbert indicates, this is a super package. This is a great opportunity to learn and have fun with no investment, and presumably sLab will reap the appropriate benefits when we all write our killer apps based on their libraries.

I had never dubbed around with an SQL-based package before, and asked Will to recommend an introduction to the language. The book he recommended is quite readable and informative. It's only shortcoming is that the accompanying CD is Windows only, but many of us now have a Wintel machine or an emulator program, and I won't tell anyone if you won't. ;-)

The Practical SQL Handbook, third ed., 1996, by Bowman, Emerson, and Darnovsky. Addison Wesley Developers Press, Reading MA. ISBN 0-201-44787-8.

-Ed Ringel


William Gilbert, http://www.informagen.com/cv/Gilbert.html, is a biochemist by training as well as a computer professional. He provides informatics solutions and scientific consulting to startup biotechnology companies. He also holds a research professorship at the University of New Hampshire in the Department of Biochemistry and Molecular Biology.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

A Better Finder Rename 9.52 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
OmniFocus 2.2.3 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
TinkerTool 5.4 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Tinderbox 6.3.1 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
Parallels Desktop 10.2.2 - Run Windows a...
Parallels Desktop is simply the world's bestselling, top-rated, and most trusted solution for running Windows applications on your Mac. With Parallels Desktop for Mac, you can seamlessly run both... Read more
Adobe Premiere Pro CC 2015 9.0.1 - Digit...
Premiere Pro CC 2015 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Premiere Pro customer). Premiere Pro CS6 is still available for... Read more
Adobe After Effects CC 2015 13.5.1 - Cre...
After Effects CC 2015 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). After Effects CS6 is still available... Read more
Adobe Creative Cloud 2.2.0.129 - Access...
Adobe Creative Cloud costs $49.99/month (or less if you're a previous Creative Suite customer). Creative Suite 6 is still available for purchase (without a monthly plan) if you prefer. Introducing... Read more
Tower 2.2.3 - Version control with Git m...
Tower is a powerful Git client for OS X that makes using Git easy and more efficient. Users benefit from its elegant and comprehensive interface and a feature set that lets them enjoy the full power... Read more
Apple Java 2015-001 - For OS X 10.7, 10....
Apple Java for OS X 2015-001 installs the legacy Java 6 runtime for OS X 10.11 El Capitan, OS X 10.10 Yosemite, OS X 10.9 Mavericks, OS X 10.8 Mountain Lion, and OS X 10.7 Lion. This package is... Read more

Domino Drop (Games)
Domino Drop 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Domino Drop is a delightful new puzzle game with dominos and gravity!Learn how to play it in a minute, master it day by day.Your... | Read more »
OPERATION DRACULA (Games)
OPERATION DRACULA 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: 25% off launch sale!!! 'Could prove to be one of the most accurate representations of the Japanese bullet hell shmup... | Read more »
Race The Sun (Games)
Race The Sun 1.01 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.01 (iTunes) Description: You are a solar craft. The sun is your death timer. Hurtle towards the sunset at breakneck speed in a futile race against time.... | Read more »
Tap Delay (Music)
Tap Delay 1.0.0 Device: iOS Universal Category: Music Price: $4.99, Version: 1.0.0 (iTunes) Description: Back in the “old days”, producers and engineers created delay and echo effects using tape machines. Tap Delay combines the warm... | Read more »
This Week at 148Apps: July 20-24, 2015
July is Heating Up With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out... | Read more »
Red Game Without A Great Name (Games)
Red Game Without A Great Name 1.0.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.3 (iTunes) Description: The mechanical bird is flying through an unfriendly, Steampunk world. Help it avoid obstacles and deadly... | Read more »
Warhammer: Arcane Magic (Games)
Warhammer: Arcane Magic 1.0.2 Device: iOS Universal Category: Games Price: $9.99, Version: 1.0.2 (iTunes) Description: Engage in epic battles and tactical gameplay that challenge both novice and veteran in Warhammer: Arcane Magic, a... | Read more »
Mazes of Karradash (Games)
Mazes of Karradash 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: The city of Karradash is under attack: the monsters of the Shadow Realms are emerging from the depths.No adventurer is... | Read more »
Battle Golf is the Newest Game from the...
Wrassling was a pretty weird - and equally great - little wressling game. Now the developers, Folmer Kelly and Colin Lane, have turned their attention to a different sport: golfing. This is gonna be weird. [Read more] | Read more »
Qbert Rebooted has the App Store Going...
The weird little orange... whatever... is back, mostly thanks to that movie which shall remain nameless (you know the one). But anyway it's been "rebooted" and now you can play the fancy-looking Qbert Rebooted on iOS devices. [Read more] | Read more »

Price Scanner via MacPrices.net

2015 13-inch 2.7GHz Retina MacBook Pro on sal...
B&H Photo has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale today for $1199 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
2.8GHz Mac mini available for $988, includes...
Adorama has the 2.8GHz Mac mini available for $988, $11 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
High-Precision Battery Fuel Gauge IC Extends...
Renesas Electronics Corporation has announced its new lithium-ion (Li-ion) battery fuel gauge IC, the RAJ240500, designed to extend battery life for connected mobile devices such as tablets, notebook... Read more
27-inch 3.3GHz 5K iMac on sale for $1799, $20...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1799 including free shipping plus NY tax only. Their price is $200 off MSRP, and it’s the lowest price available for this model from any Apple... Read more
Twelve South Free Dual Screen Backgrounds Co...
Twelve South has posted a second collection of travel Desktop photos, noting: For the Twelve South team, a vacation is never just a vacation. It’s a time to try out new prototypes on the road, visit... Read more
Apple Refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $... Read more
Tablets: Why Microsoft’s Surface Is Soaring W...
In contrast to Apple’s record fiscal third quarter reported this week, Microsoft had a miserable latest quarter with its revenues falling by 5.1 percent, hammered by ongoing weak PC demand, and... Read more
Sale! 13″ 1.6GHz/256GB MacBook Air for $1099,...
B&H Photo has the 13″ 1.6GHz/256GB MacBook Air on sale for $1099 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price available for this model. Read more
iPad mini 4 To Be Upgraded To iPad Air 2 Spec...
There’s a certain inevitability about making Apple product predictions this time of year. Come September, we can pretty reliably count on the release of refreshed iPhones, along with the iOS 9... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Customer Experience (ACE) Leader - A...
…management to deliver on business objectives Training partner store staff on Apple products, services, and merchandising guidelines Coaching partner store staff on Read more
Project Manager - *Apple* Pay Security - Ap...
**Job Summary** The Apple Pay Security team is seeking a highly organized, results-driven Project Manager to drive the development of Apple Pay Security. If you are Read more
*Apple* TV Product Design Internship (Spring...
…the mechanical design effort associated with creating world-class products with the Apple TV PD Group. Responsibilities will include working closely with manufacturing, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.