Definition of irrigation. 1  1 : the therapeutic flushing of a body part with a stream of liquid. 2  2 : the watering of land by artificial means to foster plant growth.
Answer: To start with, Oracle Real Application Clusters (RAC) are a database system involving a configuration of multiple hosts or servers joined together with clustering software and accessing the shared disk storage structures.
Connecting to an Oracle RAC system is similar to connecting to a single instance of an Oracle database. When connecting to a single Oracle database instance, you specify the SID or ServiceName of the instance to which you want to connect either in the connection URL or as properties of a DataSource.