3 Syntax Rules for Configuration Files

Learn the syntax rules for configuring Oracle Net Services parameters, keywords, addresses, and naming methods.

3.1 Overview of Configuration File Syntax

Create Oracle Net Services configuration files using syntax rules and standard conventions.

The Oracle Net Services configuration files contain parameters that include keyword-value pairs. Keyword-value pairs are surrounded by parentheses:


Some keywords have other keyword-value pairs as their values:


For example, the address portion of the local naming configuration file (tnsnames.ora) can include lines such as:


Set up your configuration files using indentation to show what keyword is the parent or owner of other keyword-value pairs. If you do not indent your files this way, then you must still indent a wrapped line by at least one space, or it will be misread as a new parameter. The following syntax is acceptable:


The following syntax is not acceptable:


3.2 Syntax Rules for Configuration Files

Follow the structure, hierarchy, and character requirements for configuration files.

The following rules apply to the configuration file syntax:

  • Any keyword in a configuration file that begins a parameter that also includes one or more keyword-value pairs must be in the far-left column of a line. If you indent the keyword by one or more spaces, then Oracle interprets the indented keyword as a continuation of the previous line.

  • All characters must be part of the network character set.

  • Keywords are not case-sensitive. However, values can be case-sensitive depending on your operating system and protocol.

  • In keyword-value pairs, spaces around the equal sign (=) are optional.

  • There is a hierarchy of keywords that requires that some keywords are always followed by others. At any level in the hierarchy, keywords can be listed in any order. For example, the following entries are equally valid:

  • Keywords cannot contain spaces.

  • Values must not contain spaces, unless the values with spaces are enclosed within double quotation marks (") or single quotation marks (').

  • If the keyword-value pair consists of a single word, or a concatenation of words on either side of the equal sign, then no parentheses are needed.

  • The maximum length of a connect descriptor is 4KB.

  • You can include comments by using the number sign (#) at the beginning of a line. Anything following the number sign to the end of the line is considered a comment.

3.3 Network Character Set for Keywords

Use the permitted character set for keyword values and network character sets.

The network character set for keyword values consists of the following characters. Connect descriptors must be made up of single-byte characters.

A-Z, a-z
( ) < > / \
, . : ; ' "=- _
$ + * # & ! % ? @

Within this character set, the following symbols are reserved:

( ) = \ " ' #

Reserved symbols are used as delimiters, not as part of a keyword or a value, unless the keyword or value has quotation marks. If you have a value that contains reserved symbols, then use either single or double quotation marks to enclose the value. To include quotation marks within a value that is surrounded by quotation marks, use different quotation marks. The backslash (\) is used as an escape character.

You can use the following characters within a connect descriptor, but not in a keyword or value:

  • Space

  • Tab

  • Carriage return

  • Newline

3.4 Permitted Listener and Net Service Name Character Set

Create listener names and net service names for clients that comply with Oracle Net Services character set requirements.

Listener names and net service names are limited to the following character set:

[a...z] [A...Z] [0...9] _

The first character in the listener name or net service name must be an alphanumeric character. In general, names up to 64 characters are acceptable. In addition, a database service name must match the global database name that is defined by the database administrator, which consists of a database name and the database domain. Both net service names and global database names are not case-sensitive.