SYS_CONNECT_BY_PATH

manager that are equal to or less than the current salary. You can see that Raphaely and Cambrault have the same cumulative total. This is because Raphaely and Cambrault have the identical salaries, so Oracle adds together their salary values and applies the same cumulative total to both rows.

SELECT manager_id, last_name, salary,

SUM(salary) OVER (PARTITION BY manager_id ORDER BY salary

RANGE UNBOUNDED PRECEDING) l_csum

FROM employees;

SYS_CONNECT_BY_PATH

Syntax sys_connect_by_path::=

SYS_CONNECT_BY_PATH ( column , char )

Purpose

SYS_CONNECT_BY_PATH is valid only in hierarchical queries. It returns the path of a column value from root to node, with column values separated by char for each row returned by CONNECT BY condition.

Functions 6-155

SYS_CONTEXT

Both column and char can be any of the datatypes CHAR, VARCHAR2, NCHAR, or NVARCHAR2. The string returned is of VARCHAR2 datatype and is in the same character set as column.

See Also: "Hierarchical Queries" on page 8-3 for more information about hierarchical queries and CONNECT BY conditions

Examples

The following example returns the path of employee names from employee Kochhar to all employees of Kochhar (and their employees):

SELECT LPAD(’ ’, 2*level-1)||SYS_CONNECT_BY_PATH(last_name, ’/’) "Path" FROM employees

START WITH last_name = ’Kochhar’

CONNECT BY PRIOR employee_id = manager_id;

Path

---------------------------------------------------------------

/Kochhar

/Kochhar/Greenberg

/Kochhar/Greenberg/Faviet

/Kochhar/Greenberg/Chen

/Kochhar/Greenberg/Sciarra

/Kochhar/Greenberg/Urman

/Kochhar/Greenberg/Popp

/Kochhar/Whalen

/Kochhar/Mavris

/Kochhar/Baer

/Kochhar/Higgins

/Kochhar/Higgins/Gietz

SYS_CONTEXT

Syntax sys_context::=

6-156 Oracle9i SQL Reference

SYS_CONTEXT

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 (constant) 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. The valid range of values is 1 to 4000 bytes. (If you specify an invalid value, then Oracle ignores it and uses the default.)

Oracle9i provides a built-in namespace called USERENV, which describes the current session. The predefined parameters of namespace USERENV are listed Table 6–2 on page 6-158, along with the lengths of their return strings.

Restriction on SYS_CONTEXT You cannot specify this function in a parallel query.

See Also:

■Oracle9i Application Developer’s Guide - Fundamentals for information on using the application context feature in your application development

■CREATE CONTEXT on page 13-12 for information on creating user-defined context namespaces

■Oracle9i Supplied PL/SQL Packages and Types Reference for information on the DBMS_SESSION.set_context procedure

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’)

------------------------------------------------------

Functions 6-157

SYS_CONTEXT

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 6–2 Predefined Parameters of Namespace USERENV

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SYS_CONTEXT

Table 6–2 (Cont.) Predefined Parameters of Namespace USERENV

Functions 6-159

SYS_CONTEXT

Table 6–2 (Cont.) Predefined Parameters of Namespace USERENV

6-160 Oracle9i SQL Reference