The tool is currently implemented as a Ruby Domain Specific Language (DSL). It also comes with a nice commandline tool for using the algebra in shell with a pipe-and-filter *nix philosophy.
Alf can query multiple and various sources of data, including but not restricted to SQL databases. It has a smart compiler that delegates to the underlying engines what can be delegated.
Despite providing a nice tool for querying traditional data-bases, Alf aims at investigating the following research questions:
- How far can we use the closure property of relational algebra as an abstraction mechanism for software engineering? Do SQL engines support very complex query plans? How can logical query optimization help?
- Is modern relational algebra on top of a powerful type system enough to query multiple heterogeneous data sources? What connectors do we need?
- What high-level relational operators do software engineers invent if provided with a way to create their own?
- How do we truly reconcile multiple type systems when it comes to manipulating and passing data aound? e.g. Ruby (more generally a host language), SQL (an underlying database engine), JSON/XML (for data transfer), etc.
- Can we come with a pragmatic, intuitive, yet sound proposal for view updating on top of a well selected subset of relational operators?
- How well can we integrate (sound) query languages with host programming languages following a DSL approach?
We are currently looking for collaborations within the academic world and with industrial partners interrested in investing in this kind of approach. Drop us an email if interrested.
Who and where?Alf is developed by Bernard Lambeau at the University of Louvain. The tool source code is available on github. This work is partially supported by the Regional Government of Wallonia (PIPAS project, RW Conv. 1017087).
Copyright (c) 2011-2014 - Bernard Lambeau & The University of Louvain (Belgium) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.