Query Abstraction Layer: Difference between revisions

Revision as of 23:08, 23 September 2020

Revision as of 00:27, 24 March 2022

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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]], [[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]</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.