OMOP/README.md

Common Data Model v5.1.1
=================

See full CDM specification file on our github [wiki](https://github.com/OHDSI/CommonDataModel/wiki) or in the [CDM V5.1.1 PDF](https://github.com/OHDSI/CommonDataModel/blob/master/OMOP_CDM_v5_1_1.pdf)

Release Notes for v5.1.1
=============
This version has a small bug-fix for impala to make it compatible with ATLAS cohort generation.

Release Notes for v5.1.0
=============
This version is based on the CDM working group proposal [#60](https://github.com/OHDSI/CommonDataModel/issues/60) and [#59](https://github.com/OHDSI/CommonDataModel/issues/59) and is **backwards compatibile with v5.0.1**. The proposed and accepted changes include adding a datetime field to every table that had a date column and adding field DENOMINATOR_VALUE to the DRUG_STRENGTH table. These were the new columns added:

**PERSON**  
* birth_datetime, not required

**SPECIMEN**  
* specimen_datetime, not required

**DEATH**  
* death_datetime, not required

**VISIT_OCCURRENCE**  
* visit_start_datetime, not required
* visit_end_datetime, not required

**PROCEDURE_OCCURRENCE**  
* procedure_datetime, not required

**DRUG_EXPOSURE**  
* drug_exposure_start_datetime, not required
* drug_exposure_end_datetime, not required

**DRUG_STRENGTH**
* DENOMINATOR_VALUE, not required

**DEVICE_EXPOSURE**  
* device_exposure_start_datetime, not required
* device_exposure_end_datetime, not required

**CONDITION_OCCURRENCE**  
* condition_start_datetime, not required
* condition_end_datetime, not required

**MEASUREMENT**  
* measurement_datetime as time, not required

**OBSERVATION**  
* observation_datetime, not required

**NOTE**  
* note_datetime, not required

There are additional changes listed on the [OHDSI wiki](http://www.ohdsi.org/web/wiki/doku.php?id=documentation:next_cdm) that have been accepted but are not listed in this version because after being accepted they were never added to the DDL. Version 5.1.0 as it is now is being used by members of the community and any changes would cause problems so the additional accepted proposals will be added in subsequent versions. 

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This repo contains the definition of the OMOP Common Data Model. It supports the 5 SQL technologies: Impala, Oracle, Postgres, Redshift, and SQL Server. For each, the DDL, constraints and indexes (if appropriate) are defined. 

Versions are defined using tagging and versioning. Full versions (V6, 7 etc.) are released each year (1-Jan) and are not backwards compatible. Minor versions (V5.1, 5.2 etc.) are released each quarter (1-Apr, 1-Jul and 1-Sep) and are not guaranteed to be backwards compatible though an effort is made to make sure that current queries will not break. Micro versions (V5.1.1, V5.1.2 etc.) are released irregularly and often, and contain small hot fixes or backward compatible changes to the last minor version.