= activefacts

* http://dataconstellation.com/ActiveFacts/

== DESCRIPTION:

ActiveFacts is a semantic modeling toolkit, comprising an implementation
of the Constellation Query Language, the Constellation API, and code
generators that receive CQL or ORM (Object Role Modeling files, from
NORMA) to emit CQL, Ruby and SQL.

Semantic modeling is a refinement of fact-based modeling techniques
that draw on natural language verbalisation and formal logic. Fact
based modeling is essentially the same as relational modeling in the
sixth normal form. The tools provided here automatically condense
that to third normal form for efficient storage. They also generate
object models as a Ruby module which has an effective mapping to
both the original semantic model and to the generated SQL.

The result is a formal language that reads like plain English, and
allows creation of relational and object models that are guaranteed
equivalent, and much more stable in the face of schema evolution than
SQL is.

== FEATURES/PROBLEMS:

 * Queries are parsed, but not yet generated to SQL. DDL is complete.

 * SQL generation handles some one-to-one relationships wrongly,
   including subtypes when independent of the supertype's table.

 * The Constellation API lacks SQL persistence (but is already useful;
   the CQL compiler uses the generated Ruby code extensively)

 * Re-invoking a fact type to add new readings doesn't work

 * Some types of external constraints (when adjectives mis-match)
   don't yet pass the CQL parser's semantic analysis.

 * Validation of semantic models (and many other areas) is incomplete

 * There's no interactive CQL interpreter yet; the cql command merely
   shows the parse tree.

== SYNOPSIS:

  afgen --sql/server myfile.cql
  afgen --ruby myfile.cql
  afgen --cql myfile.orm

== REQUIREMENTS:

* Treetop parser generator
* Optional: NORMA, see <http://www.ormfoundation.org/files/>
  (needs Visual Studio pro edition), if you want to use ORM

== INSTALL:

* sudo gem install activefacts

== LICENSE:

Copyright (c) 2008 Clifford Heath.

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the
use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.