Query Abstraction Layer
| Query Abstraction Layer | |
|---|---|
| Developer(s) | Nicklas Börjesson |
| Initial release | September 2013[1] |
| Stable release | 0.4.0[2]
/ October 31, 2014 |
| Written in | Python |
| Operating system | Cross-platform |
| Type | Python libraries |
| License | BSD license |
| Website | www |
QAL is an open source development project that aims to create a collection of libraries for mixing, moving, merging, substituting and transforming data. And in some cases, like for MongoDB, schemas.
Sources and destinations include different database backends, file formats like .csv, XML and spreadsheets. Even untidy HTML web pages can be used as both a source and destination.
For SQL/RDBMS backends, it has a database abstraction layer that supports basic connectivity to Postgres, MySQL, DB2, Oracle and MS SQL server[3]. It uses XML formats(the SQL schema is self-generated) for representation of queries, transformation and merging, making it all scriptable.
With regards to SQL, QAL uses a subset of SQL features[4] and data types[5], which while obviously not complete however is sufficient for most usages. It is however easy to instead use backend specific SQL when the queries do not have to be backend-agnostic.
It is currently distributed as a Python Library (.egg)[6] and a Debian package file(.deb)[7].
It is related to the Optimal BPM(Business Process Management) project. In fact, the Optimal BPM sourceforge project used to be DAL/QAL.[1]