Oracle® Database SQL Reference 10g Release 2 (10.2) Part Number B14200-01 |
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Syntax
Purpose
SYS_CONTEXT
returns the value of parameter
associated with the context namespace
. You can use this function in both SQL and PL/SQL statements.
For namespace
and parameter
, you can specify either a string or an expression that resolves to a string designating a namespace or an attribute. The context namespace
must already have been created, and the associated parameter
and its value must also have been set using the DBMS_SESSION
.set_context
procedure. The namespace
must be a valid SQL identifier. The parameter
name can be any string. It is not case sensitive, but it cannot exceed 30 bytes in length.
The datatype of the return value is VARCHAR2
. The default maximum size of the return value is 256 bytes. You can override this default by specifying the optional length
parameter, which must be a NUMBER
or a value that can be implicitly converted to NUMBER
. The valid range of values is 1 to 4000 bytes. If you specify an invalid value, then Oracle Database ignores it and uses the default.
Oracle provides a built-in namespace called USERENV
, which describes the current session. The predefined parameters of namespace USERENV
are listed in Table 5-11.
See Also:
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Examples
The following statement returns the name of the user who logged onto the database:
CONNECT OE/OE SELECT SYS_CONTEXT ('USERENV', 'SESSION_USER') FROM DUAL; SYS_CONTEXT ('USERENV', 'SESSION_USER') ------------------------------------------------------ OE
The following hypothetical example returns the group number that was set as the value for the attribute group_no
in the PL/SQL package that was associated with the context hr_apps
when hr_apps
was created:
SELECT SYS_CONTEXT ('hr_apps', 'group_no') "User Group" FROM DUAL;
Table 5-11 Predefined Parameters of Namespace USERENV
Parameter | Return Value |
---|---|
ACTION |
Identifies the position in the module (application name) and is set through the DBMS_APPLICATION_INFO package or OCI. |
AUDITED_CURSORID |
Returns the cursor ID of the SQL that triggered the audit. This parameter is not valid in a fine-grained auditing environment. If you specify it in such an environment, Oracle Database always returns NULL . |
AUTHENTICATED_IDENTITY |
Returns the identity used in authentication. In the list that follows, the type of user is followed by the value returned:
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AUTHENTICATION_DATA |
Data being used to authenticate the login user. For X.503 certificate authenticated sessions, this field returns the context of the certificate in HEX2 format.
Note: You can change the return value of the |
AUTHENTICATION_METHOD |
Returns the method of authentication. In the list that follows, the type of user is followed by the method returned:
You can use |
BG_JOB_ID |
Job ID of the current session if it was established by an Oracle Database background process. Null if the session was not established by a background process. |
CLIENT_IDENTIFIER |
Returns an identifier that is set by the application through the DBMS_SESSION.SET_IDENTIFIER procedure, the OCI attribute OCI_ATTR_CLIENT_IDENTIFIER , or the Java class Oracle.jdbc.OracleConnection.setClientIdentifier . This attribute is used by various database components to identify lightweight application users who authenticate as the same database user. |
CLIENT_INFO |
Returns up to 64 bytes of user session information that can be stored by an application using the DBMS_APPLICATION_INFO package. |
CURRENT_BIND |
The bind variables for fine-grained auditing. |
CURRENT_SCHEMA |
Name of the default schema being used in the current schema. This value can be changed during the session with an ALTER SESSION SET CURRENT_SCHEMA statement. |
CURRENT_SCHEMAID |
Identifier of the default schema being used in the current session. |
CURRENT_SQL
|
CURRENT_SQL returns the first 4K bytes of the current SQL that triggered the fine-grained auditing event. The CURRENT_SQL n attributes return subsequent 4K-byte increments, where n can be an integer from 1 to 7, inclusive. CURRENT_SQL1 returns bytes 4K to 8K; CURRENT_SQL2 returns bytes 8K to 12K, and so forth. You can specify these attributes only inside the event handler for the fine-grained auditing feature. |
CURRENT_SQL_LENGTH |
The length of the current SQL statement that triggers fine-grained audit or row-level security (RLS) policy functions or event handlers. Valid only inside the function or event handler. |
DB_DOMAIN |
Domain of the database as specified in the DB_DOMAIN initialization parameter. |
DB_NAME |
Name of the database as specified in the DB_NAME initialization parameter. |
DB_UNIQUE_NAME |
Name of the database as specified in the DB_UNIQUE_NAME initialization parameter. |
ENTRYID |
The current audit entry number. The audit entryid sequence is shared between fine-grained audit records and regular audit records. You cannot use this attribute in distributed SQL statements. |
ENTERPRISE_IDENTITY |
Returns the user's enterprise-wide identity:
The value of the attribute differs by proxy method:
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FG_JOB_ID |
Job ID of the current session if it was established by a client foreground process. Null if the session was not established by a foreground process. |
GLOBAL_CONTEXT_MEMORY |
Returns the number being used in the System Global Area by the globally accessed context. |
GLOBAL_UID |
Returns the global user ID from Oracle Internet Directory for Enterprise User Security (EUS) logins; returns null for all other logins. |
HOST |
Name of the host machine from which the client has connected. |
IDENTIFICATION_TYPE |
Returns the way the user's schema was created in the database. Specifically, it reflects the IDENTIFIED clause in the CREATE /ALTER USER syntax. In the list that follows, the syntax used during schema creation is followed by the identification type returned:
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INSTANCE |
The instance identification number of the current instance. |
INSTANCE_NAME |
The name of the instance. |
IP_ADDRESS |
IP address of the machine from which the client is connected. |
ISDBA |
Returns TRUE if the user has been authenticated as having DBA privileges either through the operating system or through a password file. |
LANG |
The ISO abbreviation for the language name, a shorter form than the existing 'LANGUAGE ' parameter. |
LANGUAGE |
The language and territory currently used by your session, along with the database character set, in this form:
language_territory.characterset |
MODULE |
The application name (module) set through the DBMS_APPLICATION_INFO package or OCI. |
NETWORK_PROTOCOL |
Network protocol being used for communication, as specified in the 'PROTOCOL =protocol ' portion of the connect string. |
NLS_CALENDAR |
The current calendar of the current session. |
NLS_CURRENCY |
The currency of the current session. |
NLS_DATE_FORMAT |
The date format for the session. |
NLS_DATE_LANGUAGE |
The language used for expressing dates. |
NLS_SORT |
BINARY or the linguistic sort basis. |
NLS_TERRITORY |
The territory of the current session. |
OS_USER |
Operating system user name of the client process that initiated the database session. |
POLICY_INVOKER |
The invoker of row-level security (RLS) policy functions. |
PROXY_ENTERPRISE_IDENTITY |
Returns the Oracle Internet Directory DN when the proxy user is an enterprise user. |
PROXY_GLOBAL_UID |
Returns the global user ID from Oracle Internet Directory for Enterprise User Security (EUS) proxy users; returns NULL for all other proxy users. |
PROXY_USER |
Name of the database user who opened the current session on behalf of SESSION_USER . |
PROXY_USERID |
Identifier of the database user who opened the current session on behalf of SESSION_USER . |
SERVER_HOST |
The host name of the machine on which the instance is running. |
SERVICE_NAME |
The name of the service to which a given session is connected. |
SESSION_USER |
For enterprises users, returns the schema. For other users, returns the database user name by which the current user is authenticated. This value remains the same throughout the duration of the session. |
SESSION_USERID |
Identifier of the database user name by which the current user is authenticated. |
SESSIONID |
The auditing session identifier. You cannot use this attribute in distributed SQL statements. |
SID |
The session number (different from the session ID). |
STATEMENTID |
The auditing statement identifier. STATEMENTID represents the number of SQL statements audited in a given session. |
TERMINAL |
The operating system identifier for the client of the current session. In distributed SQL statements, this attribute returns the identifier for your local session. In a distributed environment, this is supported only for remote SELECT statements, not for remote INSERT , UPDATE , or DELETE operations. (The return length of this parameter may vary by operating system.) |
Table 5-12 lists the parameters of namespace USERENV
that have been deprecated. Oracle suggests that you use the alternatives suggested in the Comments column.
Table 5-12 Deprecated Parameters of Namespace USERENV
Parameter | Comments |
---|---|
AUTHENTICATION_TYPE |
This parameter returned a value indicating how the user was authenticated. The same information is now available from the new AUTHENTICATION_METHOD parameter combined with IDENTIFICATION_TYPE . |
CURRENT_USER |
Use the SESSION_USER parameter instead. |
CURRENT_USERID |
Use the SESSION_USERID parameter instead. |
EXTERNAL_NAME |
This parameter returned the external name of the user. More complete information can now be obtained from the AUTHENTICATED_IDENTITY and ENTERPRISE_IDENTITY parameter. |