document oak-run for RDB
@@ -69,7 +69,15 @@ see supported options
### DocumentNodeStore - RDB
-<<TBD>>
+To connect to a relational database specify the JDBC URL and add database user and password as optional arguments:
+
+ java -cp ... org.apache.jackrabbit.oak.run.Main <command> jdbc:... --rdbjdbcuser user --rdbjdbcpasswd password
+
+Note that the oak-run JAR file lacks several RDB specific JAR files that need to be added to the classpath:
+
+1. tomcat-jdbc-8.5.*.jar (Apache Tomcat JDBC connection pool)
+2. juli-6.0.*.jar (Apache Tomcat Logger)
+3. Whatever JDBC driver is needed to connect to the database
## BlobStore
