From 8f8e402e5efe908531d4f91e559fcd5989d11b72 Mon Sep 17 00:00:00 2001 From: clairblacketer Date: Tue, 20 Jun 2017 16:41:41 -0400 Subject: [PATCH] Update README.md --- README.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/README.md b/README.md index 358704e..f837724 100644 --- a/README.md +++ b/README.md @@ -44,7 +44,8 @@ This version is bases on this CDM working group [proposal](http://www.ohdsi.org **NOTE** * note_datetime, not required -======= +--------- + This repo contains the definition of the OMOP Common Data Model. It supports the 4 SQL technologies: Impala, Oracle, Postgres 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 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.