Oracle R Enterprise client components connect an R session to an Oracle Database instance and the Oracle R Enterprise server components. The connection makes the data in a database schema available to the R user. It also makes the processing power, memory, and storage capacities of the database server available to the R session through the Oracle R Enterprise client interface.
This section has the following topics:
To begin using Oracle R Enterprise, you first connect to a schema in an Oracle Database instance with the ore.connect function.
To begin using Oracle R Enterprise, you first connect to a schema in an Oracle Database instance with the ore.connect function. Only one Oracle R Enterprise connection can exist at a time during an R session. If an R session is already connected to the database, then invoking ore.connect terminates the active connection before opening a new connection. Before attempting to connect, you can discover whether an active connection exists by using the ore.is.connected function.
You explicitly end a connection with the ore.disconnect function. If you do not invoke ore.disconnect, then the connection is automatically terminated when the R session ends.
With the type argument of ore.connect, you specify the type of connection, either ORACLE or HIVE. A HIVE type of connection connects to Hive tables in a Hadoop cluster. An ORACLE type of connection connects to a schema in an Oracle Database instance. The default value of type is "ORACLE".
If the connection type is HIVE, then ore.connect ignores all other arguments. The HIVE option applies only if you are using Oracle R Advanced Analytics for Hadoop (ORAAH) in conjunction with a Hadoop cluster. ORAAH is part of the Oracle Big Data Connectors option to the Big Data Appliance.
If the connection type is ORACLE, then you do the following:
Use the logical all argument to specify whether Oracle R Enterprise automatically creates an ore.frame object for each table to which the user has access in the schema and makes those ore.frame objects visible in the current R session. The ore.frame objects contain metadata about the tables. The default value of the all argument is FALSE.
If all = TRUE, then Oracle R Enterprise implicitly invokes the ore.sync and ore.attach functions. If all = FALSE, then the user must explicitly invoke ore.sync to create ore.frame objects. To access these objects by name, the user must invoke ore.attach to include the names in the search path.
Use either the conn_string argument, or various combinations of the user, sid, host, password, port, service_name, and conn_string arguments to specify information that identifies the connection.
To avoid using a clear-text password, you can specify an Oracle wallet password with the conn_string argument. No other arguments are needed. By specifying an Oracle wallet password, you can avoid embedding a database user password in application code, batch jobs, or scripts.
With the other connection identifier arguments, you specify a database user name, host name, and password, and either a system identifier (SID) or service name, and, optionally, a TCP port, or you specify a database user name, password, and a conn_string argument.
The default value of the port argument is 1521, the default value of host is "localhost", which specifies the local host, and the default value of conn_string is NULL. You specify the local host when your R session is running on the same computer as the Oracle Database instance to which you want to connect.
See Also:
"Using the ore.connect and ore.disconnect Functions" for examples of using the various connection identifiers
Oracle R Enterprise Installation and Administration Guide for information on creating an Oracle wallet.
To explicitly end the connection between an R session and the Oracle Database instance, invoke the ore.disconnect function.
Oracle R Enterprise implicitly invokes ore.disconnect if you do either of the following:
Quit the R session.
Invoke ore.connect while an Oracle R Enterprise connection is already active.
When you disconnect the active connection, Oracle R Enterprise discards all Oracle R Enterprise objects that you have not explicitly saved in an Oracle R Enterprise datastore.