ALTER SESSION v13

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Name

ALTER SESSION -- change a runtime parameter.

Synopsis

ALTER SESSION SET <name> = <value>

Description

The ALTER SESSION command changes runtime configuration parameters. ALTER SESSION only affects the value used by the current session. Some of these parameters are provided solely for compatibility with Oracle syntax and have no effect whatsoever on the runtime behavior of Advanced Server. Others will alter a corresponding Advanced Server database server runtime configuration parameter.

Parameters

name

Name of a settable runtime parameter. Available parameters are listed below.

value

New value of parameter.

Configuration Parameters

The following configuration parameters can be modified using the ALTER SESSION command:

  • NLS_DATE_FORMAT (string)

    Sets the display format for date and time values as well as the rules for interpreting ambiguous date input values. Has the same effect as setting the Advanced Server datestyle runtime configuration parameter.

  • NLS_LANGUAGE (string)

    Sets the language in which messages are displayed. Has the same effect as setting the Advanced Server lc_messages runtime configuration parameter.

  • NLS_LENGTH_SEMANTICS (string)

    Valid values are BYTE and CHAR. The default is BYTE. This parameter is provided for syntax compatibility only and has no effect in the Advanced Server.

  • OPTIMIZER_MODE (string)

    Sets the default optimization mode for queries. Valid values are ALL_ROWS, CHOOSE, FIRST_ROWS, FIRST_ROWS_10, FIRST_ROWS_100, and FIRST_ROWS_1000. The default is CHOOSE. This parameter is implemented in Advanced Server.

  • QUERY_REWRITE_ENABLED (string)

    Valid values are TRUE, FALSE, and FORCE. The default is FALSE. This parameter is provided for syntax compatibility only and has no effect in Advanced Server.

  • QUERY_REWRITE_INTEGRITY (string)

    Valid values are ENFORCED, TRUSTED, and STALE_TOLERATED. The default is ENFORCED. This parameter is provided for syntax compatibility only and has no effect in Advanced Server.

Examples

Set the language to U.S. English in UTF-8 encoding. Note that in this example, the value, en_US.UTF-8, is in the format that must be specified for Advanced Server. This form is not compatible with Oracle databases.

ALTER SESSION SET NLS_LANGUAGE = 'en_US.UTF-8';

Set the date display format.

ALTER SESSION SET NLS_DATE_FORMAT = 'dd/mm/yyyy';
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