Formula Overview

Formulas have two multiple uses in Pentaho Metadata. 

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The second use is in the definition of Physical Table Columns.  In addition to Physical table columns mapping directly to a database table column, physical table columns defined in Pentaho Metadata may also be defined as a formula. This allows for combining of multiple columns into a single column, and also for doing more advanced aggregate calculations within aggregate table definitions.

The third use is in the definition of complex joins within business model relationships.  This allows for multiple key joins as well as other logic when joining tables.

The fourth use is row level security.

Under the covers, Pentaho Metadata uses JFreeReport's libFormula package for interpreting formulas.  The goal is to support OpenFormula syntax within the Metadata environment.  Formulas are first interpreted by libFormula, and then within the Metadata system are converted to native SQL depending on the type of database used.

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