Query Abstraction Layer: Difference between revisions

Revision as of 09:43, 14 January 2016

Revision as of 09:50, 14 January 2016

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Sources and destinations include different database backends, file formats like [[comma-separated values|<code>.csv</code>]], [[XML]] and spreadsheets. Even [[tag soup|untidy HTML]] web pages can be used as both a source and destination.

For [[:Category:Relational database management systems|SQL/RDBMS backends]], it has a database abstraction layer that supports basic connectivity to [[Postgres]], [[MySQL]] / [[MariaDB]], [[DB2]], [[Oracle database|Oracle]] and [[MS SQL serverServer]].<ref name="db types">[http://optimalbpm.se/api/qal/_modules/qal/dal/types.html#db_types Database backends]</ref> It uses XML formats (the SQL schema is self-generated) for representation of queries, transformation and merging, making it all scriptableprocessable by scripts.

With regards to [[SQL]], QAL uses a subset of SQL features<ref>[http://optimalbpm.se/api/qal/qal.sql.html#qal.sql.sql SQL features supported]</ref> and data types,<ref>[http://optimalbpm.se/api/qal/_modules/qal/sql/types.html#data_types SQL data types]</ref> 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 (<code>.egg</code>)<ref>[https://pypi.python.org/pypi/qal PyPi repository page]</ref> and a [[Debian package]] file ([[deb (file format)|<code>.deb</code>]]).<ref>[https://sourceforge.net/projects/qal/files/?source=navbar Downloadable files]</ref>

It is related to the [[Optimal BPM]] ([[Business Process Management]]) project.<ref>[http://www.optimalbpm.se Optimal BPM site]</ref> The Optimal BPM [[SourceForge]] project used to be DAL/QAL.<ref name="Break out"/>