Query Abstraction Layer: Difference between revisions

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| website = {{URL|http://www.optimalbpm.se/wiki/index.php/QAL}}

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'''QAL''' is an open -source development project that aims to create a collection of libraries for mixing, moving, merging, substituting and transforming data;<ref name="sf_project">[https://sourceforge.net/projects/qal/ Sourceforge project page]</ref> also in some cases, such as [[MongoDB]], [[database schema|schema]]s.

== Description ==

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]], [[IBM DB2|DB2Db2]], [[Oracle database|Oracle]] and [[MS SQL Server]].<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 processable 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]{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and data types,<ref>[http://optimalbpm.se/api/qal/_modules/qal/sql/types.html#data_types SQL data types]{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</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>

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==References==

{{Reflist|30em}}

{{CC-notice|cc=zero|url= httphttps://sourceforge.net/projects/qal/ httphttps://sourceforge.net/projects/qal/}}

==External links==

* [http://www.optimalbpm.se/wiki/index.php/ QAL Documentation and examples]{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}

* [http://optimalbpm.se/api/qal/index.html API documentation] {{Webarchive|url=https://web.archive.org/web/20170909131730/http://optimalbpm.se/api/qal/index.html |date=2017-09-09 }}

[[Category:Python (programming language) libraries]]