DeltaAccess: 'Describe' & 'Identify'
A SQL interface to DELTA (Description Language for Taxonomy), implemented in Microsoft Access

User Guide and Documentation

Copyright G. Hagedorn    Version 1.6.    Date of last change: 31.07.99

Main Table of Contents

First steps
   Conditions of use and acknowledgments
   Revision history

   Concepts of structured data storage
   Single versus multiple projects
   Strategy and future development of DeltaAccess
   Database subsystems
   Software architecture of DeltaAccess
   DELTA software sources on the internet
   The Switchboard
   Introduction to the main DeltaAccess dialog box

Import and Export of DELTA Files
   Importing data
   Which DELTA files should be imported?
   What happened to the character name during import?
   What happened to my units?
   Importing subsets (include/exclude items/characters)
   Exporting data
   Creating natural language item descriptions
   Creating item descriptions as HTML forms
   Re-importing data posted by item descriptions HTML forms

Project Management
   Managing projects
   Creating new projects
   Character subsets
   Item subsets
   Overwriting project data
   Appending data to a project
   Backup and restore

Data Analysis
   Analyzing data
   Printing the analyses
   Analyzing parts or subsets of your data
   Using Access query design (QBE editor)
   Creating a cross-tabulation or pivot analysis in Excel
   Frequency distribution (histogram) of numerical characters
   Comparing characters with external classifications
   Summarizing items
   List of all analysis queries and reports available
   Analysis queries provided
   Analysis reports provided
   Analysis charts/graphs provided

Editing, basics
   Editing overview
   General hints on Windows operations
   The Windows clipboard
   Introduction to working with Access forms

Editing, project data
   Editing the item definition (ItemEdit-form)
   Editing multiple items simultaneously (MultiItemEdit-form)
   Editing the character definition (CharEdit-form)
   Editing character headings
   Editing link groups
   Reorganize definition (characters, states, headings, or items)
   Editing project properties

Editing, special topics
   Calculated characters
   Mapping character states (key states)
Interactive identification
   Introduction to interactive identification
   Identify in comparison with other identification software
   DELTA based interactive identification outside the realm of taxonomy
   Interactive identification: The Identify dialog box
   Compiling a project for interactive identification

Appendix 1: Advanced database administration information
   Fingerprinting data sets
   Securing an Access database
   Repairing a corrupted Access database
   Linking to other data sources
   Linking to other database subsystems
   Merging descriptor projects (data sets)

Appendix 2: Development documentation
   Recognized DELTA directives
   General development information
   Co-development issues
   Multi-language support

Appendix 3: Information model and data dictionary
   The information model of DeltaAccess
   List of entities and attributes
   Detailed attribute information
   Introduction to the concept of modifiers

Appendix 4: References, Glossary
   Literature references
   Glossary of terms and procedures


 DELTA and DeltaAccess:

 Using a database for descriptive biological data:

 Usage of DeltaAccess:


Copyright G. Hagedorn    Version 1.6.    Date of last change: 31.07.99

Main table of contents


Software: This utility is distributed free of charge, including the source code (see Conditions of use). It is not, however, a stand-alone application. To run DeltaAccess you must have Windows 95 or Windows NT 4.0 and Microsoft Access 97 (= Access version 8) installed on your computer.

A run-time version of Microsoft Access exists, but I do not have a license to supply it. Since DeltaAccess is designed to help you manage your data in the context of the standard Microsoft Access database functionality (like the ability to create your own queries, forms and reports, which is not part of the run-time version) a run-time version is of limited value. Nevertheless, some work has been done (e.g. the Switchboard form) to allow DeltaAccess to function under a run-time version in the future.

Hardware: Microsoft Access is a resource hog (even Microsoft acknowledges that!). I recommend at least 16 MB RAM under Windows 95 and 32 MB RAM under Windows NT 4.0. DeltaAccess itself consists largely of VBA/DAO code. It could thus be ported to the less memory demanding Visual Basic, but I will not be doing this. Since the price of 16 MB RAM has fallen below the price of a single scientific book, I do not consider it worth the effort and problems of parallel development. Anyone volunteering to do so is welcome.

Size of database files: Microsoft Access databases can become quite large. In general, the mdb-file is about 8 times as large as your DELTA text file, plus the base-size of the application plus ca. 0.5 MB/project for the forms you usually create. This will be the compressed size, Microsoft Access uses more space during operation. For example with an 800 kB import file, you should have 15-30 MB available on your hard disk. This should not be a problem with today's large hard disks.

Speed: Most of the development and testing is still done on a computer with a 486 processor at 100 MHz. Faster processors are nicer, of course, especially as the import process is relatively slow. Import takes about 1 minute for setup (creating tables, relations, and forms), plus a data set size dependent time of about 1 minute per 100 kB (on a Pentium 100 MHz). You need only import your project once, however; subsequently you can just open the database and edit or analyze it. Microsoft Access is a database that performs many operations on the hard disk, whereas other specialized programs perform such operations in the much faster RAM memory. The advantage is that your data sets can become much larger when using a database.

See the chapter Software architecture of DeltaAccess for a discussion of the advantages of using a relational database and the advantages and disadvantages of using Microsoft Access.

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DeltaAccess is distributed as a self-expanding compressed file. To install, simply execute the downloaded file (e. g. double-click on it in the Windows Explorer) and follow the prompts. All files should be kept in the same directory. It is advisable to create a new directory into which all files from the self expanding archive are written.

There is no need for further installation of DeltaAccess if Microsoft Windows 95/Windows NT 4.0 and Microsoft Access have been properly installed. To start the DeltaAccess application, double-click on the file 'DeltaAccess.mdb' in Windows Explorer. Alternatively, you can first start Microsoft Access 97 and open the file using the menu (File, Open).

If you have problems at this point, please read the chapters on Requirements and Troubleshooting.

Upgrading existing DeltaAccess projects: The most important thing is that you rename the earlier version to a file name other than DeltaAccess.mdb (e. g. to 'DABackup15.mdb') to avoid overwriting the file with the new version. Alternatively, you could copy it to a separate folder. When you open a new version of DeltaAccess.mdb, in which no projects have been defined yet, you are asked whether you want to upgrade existing projects from earlier versions of DeltaAccess. Once you have selected the file containing the projects of your previous version, all existing projects will be upgraded to the new version.

If you want to upgrade only some projects, or if problems occurred, you can manually restore selected projects. Use the management action Restore from mdb to restore projects either from your earlier version of the DeltaAccess.mdb file or from any backup file created with the Backup to mdb-file action (present both in the management and the export dialog box).

Should you wish to add a shortcut to the programs menu (start button), drag the file 'DeltaAccess.mdb' with the right mouse button, drop it in: C:\Windows\Startmenu\Programs or another appropriate folder, and select create shortcut from the pop-up menu which appears when you drop the file. You can also drag the file directly onto the start button, which will automatically create a shortcut in the Start menu itself.

The primary address for the distribution of DeltaAccess is http:// /Projects/DeltaAccess/. Updates will be announced at that site.

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 Conditions of use and acknowledgments

DeltaAccess is free software. You can redistribute or modify the application under the terms of the GNU General Public License ver. 2, as published by the Free Software Foundation. It is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License (FSF_GPL2.TXT) for more details. If this file is missing, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

The source code of this application is not read-protected and you may modify it to suit your needs. As long as significant portions of my code remain, you must give appropriate credits and you may not charge for it beyond a handling fee (e. g. for sending out diskettes). Note that this 'User guide and documentation for DeltaAccess' is not included in the GNU General Public License for the application. It may be freely redistributed, but no modifications or incorporation of parts of it into another free program are allowed without first obtaining a license to do so.

I encourage you to join me in the effort to improve this software by sending in additions or improvements and I promise to credit such efforts appropriately. I reserve the right to use part of the current code in future versions of a similar program, for which a fee might be charged. If you want to sell a program based on or integrating parts of the current code, but with significantly enhanced functionality, you must purchase a license for commercial purposes. No code or functionality sent in by users for integration into DeltaAccess, as suggested above, will ever become part of a commercial version. Thus your cooperation in the development of DeltaAccess will ensure that there is always a free, up-to-date version of this application available.

I assert that I am the author of the distributed code and documentation, unless marked otherwise. Any opinions, findings, or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the BBA.

Copyright Gregor Hagedorn © 1995-1999. All rights reserved.
Institute for Plant Virology, Microbiology and Biosafety,
BBA, Federal Biological Research Center
Königin-Luise-Str. 19, 14195 Berlin, Germany.


Depending on the number or requests, I may or may not be able to provide support for DeltaAccess on an individual level. I therefore recommend that all usage questions (beyond beta testing problems) be addressed to the DELTA mailing list.


I wish to extend special thanks to Gerhard Rambold and Walter Berendsohn for their many suggestions and assistance with beta testing and to Mike Dallwitz, who has been most helpful and patient (despite occasional disagreements about how DELTA data should be structured). If you are interested in lichens, check out Gerhard's Lias site (! As well, I am very grateful to Désirée Maltais, who helped in correcting my English (sadly, I always introduce new errors...). Particular thanks are also due to Noel Cross, Richard Pankhurst, Per de Place Bjorn, Robin Wilson, and Joseph H. Kirkbride, Jr., for discussions and comments.

See also the next chapters Revision history and Trademarks.

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