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CHAPTER 5. Oracle Names

This chapter provides information about Oracle Names on OpenVMS. It covers the following topics:

Note: This chapter assumes that Oracle Names and all the related SQL*Net products have been installed at your site.

Introduction

The function of the Names Server is to resolve connection addresses in a homogeneous and centralized location. As a client issues a connection request, the Names Server is responsible for directing the client connection request to the appropriate listener for the specified SID. TNSNAMES.ORA can also resolve the listener address. However, the benefits of the centralized list of connection addresses that Oracle Names provides greatly eases the maintenance of large network definitions.

NAMESCTL

The NAMESCTL utility is used to start and stop the Names Server and to query its status or services. The NAMESCTL command executes the command procedure ORA_NETCONFIG:NAMESCTL.COM, which provides a shell to the executable program ORA_NETCONFIG:NAMESCTL.EXE.

The main function of the command procedure ORA_NETCONFIG:NAMESCTL.COM is to check that the privileges required to start the Names Server are present (see the section "Names Server Privileges"). If a NAMESCTL START command is entered and the required privileges are not present, an error is displayed and NAMESCTL exits.

Note: Start the Names Server using the Oracle account.

Warning: If you enter the NAMESCTL interactive mode by giving the NAMESCTL command without a subcommand and you have received a warning about inadequate privileges, DO NOT attempt to start the Names Server. The Names Server process may still start, depending on the privileges you do have, but it may not function properly.

Warning: DO NOT start the Names Server from a process that has a UIC in the system group, for example a group less than or equal to MAXSYSGROUP. If you give a NAMESCTL START command from such a process, an error is displayed and NAMESCTL exits. If you enter a NAMESCTL command with no arguments, you are warned not to start the Names Server from within the NAMESCTL utility.

Names Server Privileges

The process in which the Names Server runs must have the OpenVMS privileges in Table 5.1 to be able to perform the associated function.

Privilege Function
CMKRNL Facilitate kernel mode processing
NETMBX Use DECnet
PRMMBX Create a permanent mailbox on which to listen (The mailbox is permanent so that the logical name associated with it goes into the SYSTEM logical name table.)
SYSNAM Create SYSTEM logical names and shared logical name tables
TMPMBX Create temporary mailboxes
Note: Before attempting to start the Names Server, the process that starts the Names Server must have the privileges in this table or be able to have them set. As noted above, the NAMESCTL command file will attempt to set these privileges and warn the user if it was unable to do so.
Table 5-1 Privileges and Their Functions

Requirements

Before you can use Oracle Names, the following configuration files must be in the TNS_ADMIN directory of the system that calls Oracle Names:

NAMES.ORA

The NAMES.ORA file describes the Names Server and is read by NAMESCTL.EXE at Server startup. NAMES.ORA identifies, among other things:

SQLNET.ORA

The SQLNET.ORA file is read by both the client, as part of a connection request, and by NAMESCTL, for all operations other than server startup. This files identifies the Names service to be used to resolve the connection. Within SQLNET.ORA, the NAMES.PREFERRED_SERVERS list specifies to the client the address of the Names Server with which to connect.

Note: The presence of the NAMES.PREFERRED_SERVERS clause in SQLNET.ORA supersedes the presence of TNSNAMES.ORA in TNS_ADMIN. Therefore, if the use of a Names Server has been specified with SQLNET.ORA, then even if TNSNAMES.ORA exists and has a complete list of connection addresses, the client will not read TNSNAMES.ORA.

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