WHAT IS OOFILE? OOFILE is a c++ framework. It can be used as a "traditional" ODBMS or can be used to access a more traditional RDBMS or record-oriented database. The current release is implemented with a Faircom c-tree Plus ISAM backend on Mac and MS Windows. There would be very little difficulty in porting this to any platform supported by Faircom, and we already have over 8 OS/compiler combinations in use (including 3 in-house).
Design Goals - everything is native C++ with no (database) preprocessor required
- external interfaces to enable calling from Hypercard, Smalltalk etc.
- keep syntax very simple, familiar to 4GL users and not needing c++ gurus
- safe syntax that makes it hard to do the wrong thing by mistake, making maximum use of c++ compiler type-checking
- implement with a choice of database engines for the backend
- integrate with a range of common application frameworks
- provide additional classes for managing gui interfaces to help construct typical database applications, where features are not commonly part of application frameworks
- use a widely available level of c++ (no RTTI, templates or exception handling)
WHO IS OUR MARKET 1) c++ developers (or wannabees) wanting an embedded database for writing applications, probably working in combination with an application framework such as zApp, OWL or PowerPlant.
2) World Wide Web developers seeking a database and report-writer combination to create web pages in response to queries, searching hundreds of thousands of records (at least).
BASIC PHILOSOPHY Object-oriented design is mainly about classes, not individual objects.
OOFILE is similar. Most of the time you model your data in terms of classes. You do NOT declare individual objects (unlike the ODMG model).
Consider a database from the user's view. They generally see collections of data and edit or interact with individual records from the collection. The user doesn't care about individual object identity, they don't create symbolic names for particular objects. These things may be important inside the database, but do not need to be exposed.
SOME SIMPLE EXAMPLES Note: for more examples, including online queries, look on http://www.highway1.com.au/adsoftware/oofile.html
Before venturing into database definitions, let's consider some operations on a database containing People, Job Histories and Companies.
// print my address cout << People["Andy Dent"].Address;
// get a separate list (iterator) of people who worked for software companies dbPeople softP( People.PrevJobs->Company->MainBusiness()=="Software" );
// for the current softP record (ie person), print the number of large companies
// where they've worked, and the current company size
cout << softP.Name() << "\t"
<< (softP.PrevJobs->Company->NumEmployees() > 100).count()
<< "\t"
<< softP.CurrentJob->Company->NumEmployees() << endl;
NOTE: The () at the end of fields, as shown above, are optional for all cases except fields in relational expressions, eg: People.CurrentJob->StartDate().
DECLARING SIMPLE TABLES To define a table with a few fields, the simplest declaration would be: CLASS_TABLE(dbPeople) dbChar Name, Address; dbInt Salary; };
This defaults the size of the dbChar fields to 80 chars. To specify the size of the fields, and/or control indexing options, you need to add a constructor: CLASS_TABLE(dbPeople) dbChar Name, Address; dbInt Salary;
dbPeople : Name(40, "Name", kIndexNoDups),
Address(255, "Address"),
Salary("Salary", kIndexed)
{};
};
Note that the constructors also specify the field name strings. These are optional, but are of great benefit when writing query and report-writer logic or when constructing a database schema that should be readable by others.
SOME OTHER FEATURES - Derived fields, either specified as a combination of existing fields or user-calculated
- User-defined relations
- keyword indexing
- phonetic indexing
- inbuilt report-writer
RELATIONS One of the big features of an ODBMS is modelling the relationships between objects. OOFILE allows you to model relations in a pure ODBMS sense, using object identifiers, or explicitly perform runtime joins over database fields. This would be mainly used by people porting existing database structures. There are a number of syntaxes available to establish relationships, eg:
dbConnect_ctree theDB; // the physical database dbAcademics Academics; // a couple of tables dbStudents Students;
dbRelation Supervision("Supervision"); // a concrete relation
Supervision.Names("Supervises", "is Supervised by")
.Tables(Academics, Students)
.Links(Academics.Supervises, Students.Boss)
.JoinField(Academics.StaffNo, Students.SupervisorNo);
APPLICATION FRAMEWORKS AND OOFILE GUI Integration classes are under development for zApp & PowerPlant with more frameworks to follow. A "non-intrusive" approach has been taken of providing helper classes and instructions that let you incorporate OOFILE use into an existing program.
These helper classes include subclasses of the native edit fields, that store data directly into the database. Depending on your framework, other classes are added for displaying lists of records, managing multiple page input forms and similar business application functions.
For Macintosh users, the popular AppMaker code generator is being enhanced to generate OOFILE applications. You will be able to go from drawing your interface to a complete working database application, without writing code. The next AppMaker and CodeWarrior CD's will contain more information and samples.
STATUS The current c-tree implementation is solid and the inbuilt test data generator has been used to create databases of up to 200Mb in various configurations. The largest beta tester is operating a 270Mb+ database on a Sparc Classic. (500,000+ IP-flow objects as of mid July).
Product release, including (at least) zApp and PowerPlant integrations is anticipated for September
TEST PLATFORMS in-house c-tree+ v6.4B
Mac - Symantec c++ v7.0.4 - CodeWarrior 6.1
MS Windows - Borland c++ v4.5p3
SunOS 4.3 - g++ v2.6.3
CONTACT
Andy Dent
A.D. Software
94 Bermuda Drive
Ballajura, Western Australia 6066
Phone/Fax +61-9-249-2719
eWorld: DentA
CompuServe: 100033,3241
Internet: dent@highway1.com.au
ftp://ftp.highway1.com.au/pub/adsoftware/
http://www.highway1.com.au/adsoftware/
MAINTENANCE Priority fixes/consulting rate (drop-everything mode) $60/hour
Patches to each version - free.
Major upgrades - 30% per seat. or Annual Maintenance, regardless of number of upgrades - 40% per seat
UPGRADES Upgrading between database and report-writer options is at the cost difference.
Changing from one GUI to another is 50%. If you decide to later reactive the original, it's also at 50% (ie: net result same as buying the 2nd GUI outright).
Note: if later GUI kits are at different prices, exchange rules will vary to suit.
SITE LICENSING (Excluding bundled c-tree) by negotiation for large sites. or 40% off 2nd and subsequent copies
Andy Dent, Product Architect, A.D. Software, Western Australia OOFILE - "the cross-platform OODBMS that speaks c++" ftp://ftp.highway1.com.au/pub/adsoftware/ http://www.highway1.com.au/adsoftware/
This document was translated by ms2html v1.8 on 04.06.96.