[CDM_SOURCE](https://github.com/OHDSI/CommonDataModel/wiki/CDM_SOURCE)

All metadata about the data should be derived from the data themselves. However, the following contains a few key pieces of information that are convenient especially for software applications utilizing the CDM data.  
  
Below provides an entity-relationship diagram highlighting the tables within the Standardized Metadata portion of the OMOP Common Data Model:

![Metadata entity-relationship diagram](http://www.ohdsi.org/web/wiki/lib/exe/fetch.php?media=documentation:cdm:standard_meta_data.png)\