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

Duplicate Annihilator 5.7.5 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator... Read more
BusyContacts 1.0.2 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
Capture One Pro 8.2.0.82 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more
Backblaze 4.0.0.872 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac.With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Little Snitch 3.5.2 - Alerts you about o...
Little Snitch gives you control over your private outgoing data. Track background activity As soon as your computer connects to the Internet, applications often have permission to send any... Read more
Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more

Fast & Furious: Legacy's Creati...
| Read more »
N-Fusion and 505's Ember is Totally...
| Read more »
These are All the Apple Watch Apps and G...
The Apple Watch is less than a month from hitting store shelves, and once you get your hands on it you're probably going to want some apps and games to install. Fear not! We've compiled a list of all the Apple Watch apps and games we've been able to... | Read more »
Appy to Have Known You - Lee Hamlet Look...
Being at 148Apps these past 2 years has been an awesome experience that has taught me a great deal, and working with such a great team has been a privilege. Thank you to Rob Rich, and to both Rob LeFebvre and Jeff Scott before him, for helping me... | Read more »
Hands-On With Allstar Heroes - A Promisi...
Let’s get this out of the way quickly. Allstar Heroes looks a lot like a certain other recent action RPG release, but it turns out that while it’s not yet available here, Allstar Heroes has been around for much longer than that other title. Now that... | Read more »
Macho Man and Steve Austin Join the Rank...
WWE Immortals, by Warner Bros. Interactive Entertainment and WWE, has gotten a superstar update. You'll now have access to Macho Man Randy Savage and Steve Austin. Both characters have two different versions: Macho Man Randy Savage Renegade or Macho... | Read more »
Fearless Fantasy is Fantastic for the iF...
I actually had my first look at Fearless Fantasy last year at E3, but it was on a PC so there wasn't much for me to talk about. But now that I've been able to play with a pre-release version of the iOS build, there's quite a bit for me to talk... | Read more »
MLB Manager 2015 (Games)
MLB Manager 2015 5.0.14 Device: iOS Universal Category: Games Price: $4.99, Version: 5.0.14 (iTunes) Description: Guide your favorite MLB franchise to glory! MLB Manager 2015, officially licensed by MLB.com and based on the award-... | Read more »
Breath of Light (Games)
Breath of Light 1.0.1421 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1421 (iTunes) Description: Hold a quiet moment. Breath of Light is a meditative and beautiful puzzle game with a hypnotic soundtrack by... | Read more »
WWE WrestleMania Tags into the App Store
Are You ready to rumble? The official WWE WrestleMania app, by World Wrestling Entertainment, is now available. Now you can get all your WrestleMania info in one place before anyone else. The app offers details on superstar signings, interactive... | Read more »

Price Scanner via MacPrices.net

Samsung Galaxy S 6 and Galaxy S 6 edge U.S. P...
Samsung Electronics America, Inc. has announced the Galaxy S 6 and Galaxy S 6 edge will be available in the U.S. beginning April 10, with pre-orders being accepted now. “We have completely reimagined... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
The Apple Store has Apple Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.... Read more
Save up to $80 on iPad Air 2s, NY tax only, f...
 B&H Photo has iPad Air 2s on sale for $80 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $469.99 $30 off - 64GB iPad Air 2 WiFi: $549.99 $50 off - 128GB iPad... Read more
iMacs on sale for up to $205 off MSRP
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1019 $80 off - 21″ 2.7GHz iMac: $1189 $110 off - 21″ 2.9GHz... Read more
Färbe Technik Offers iPhone Battery Charge LI...
Färbe Technik, which manufactures and markets of mobile accessories for Apple, Blackberry and Samsung mobile devices, is offering tips on how to keep your iPhone charged while in the field: •... Read more
Electronic Recyclers International CEO Urges...
Citing a recent story on CNBC about concerns some security professionals have about the forthcoming Apple Watch, John Shegerian, Chairman and CEO of Electronic Recyclers International (ERI), the... Read more
Save up to $380 with Apple refurbished iMacs
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 – $2119 $... Read more
Mac minis on sale for up to $75 off, starting...
MacMall has Mac minis on sale for up to $75 off MSRP including free shipping. Their prices are the lowest available for these models from any reseller: - 1.4GHz Mac mini: $459.99 $40 off - 2.6GHz Mac... Read more
College Student Deals: Additional $50 off Mac...
Take an additional $50 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through April 11, 2015. Anyone with a valid .EDU email address can take advantage... Read more
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... Read more

Jobs Board

DevOps Software Engineer - *Apple* Pay, iOS...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Lead *Apple* Solutions Consultant - Retail...
**Job Summary** Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer in a hyper-business critical Reseller's store Read more
*Apple* Pay - Site Reliability Engineer - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.