NLS_COMP

Property Description

Parameter type

String

Syntax

NLS_COMP = { BINARY | LINGUISTIC | ANSI }

Default value

BINARY

Modifiable

ALTER SESSION

Basic

No

NLS_COMP specifies the collation behavior of the database session.

Values

  • BINARY

    Normally, comparisons in the WHERE clause and in PL/SQL blocks is binary unless you specify the NLSSORT function.

  • LINGUISTIC

    Comparisons for all SQL operations in the WHERE clause and in PL/SQL blocks should use the linguistic sort specified in the NLS_SORT parameter. To improve the performance, you can also define a linguistic index on the column for which you want linguistic comparisons.

  • ANSI

    A setting of ANSI is for backward compatibility; in general, you should set NLS_COMP to LINGUISTIC

Note:

Unless you explicitly set the value for NLS_COMP in your initialization parameter file, a default value of NULL is shown in the following views: V$PARAMETER, V$SYSTEM_PARAMETER, V$PARAMETER2, V$SYSTEM_PARAMETER2, and NLS_INSTANCE_PARAMETERS. However, the actual default value, and behavior, is BINARY. Note that you cannot change the default to NULL, because NULL is not among the valid values.

Examples

See Oracle Database Globalization Support Guide for examples of using this parameter.

Note:

The value of this initialization parameter NLS_COMP is used to initialize the session value of this parameter, which is the actual value referenced by the SQL query processing. This initial value is overridden by a client-side value if the client uses the Oracle JDBC driver or if the client is OCI-based and the NLS_LANG client setting (environment variable) is defined. The initialization parameter value is, therefore, usually ignored.