ATAN2

ATAN

Syntax atan::=

ATAN ( n )

Purpose

ATAN returns the arc tangent of n. The argument n can be in an unbounded range, and the function returns values in the range of -π/2 to π/2 and are expressed in radians.

Examples

The following example returns the arc tangent of .3:

SELECT ATAN(.3) "Arc_Tangent" FROM DUAL;

Arc_Tangent

----------

.291456794

ATAN2

Syntax atan2::=

Purpose

ATAN2 returns the arc tangent of n and m. The argument n can be in an unbounded range, and the function returns values in the range of -π to π, depending on the signs of n and m, and are expressed in radians. ATAN2(n,m) is the same as

ATAN2(n/m)

Examples

The following example returns the arc tangent of .3 and .2:

Functions 6-21

AVG

SELECT ATAN2(.3, .2) "Arc_Tangent2" FROM DUAL;

Arc_Tangent2

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

.982793723

AVG

Syntax avg::=

See Also: "Analytic Functions" on page 6-10 for information on syntax, semantics, and restrictions

Purpose

AVG returns average value of expr. You can use it as an aggregate or analytic function.

If you specify DISTINCT, then you can specify only the query_partition_ clause of the analytic_clause. The order_by_clause and windowing_ clause are not allowed.

See Also:

Aggregate Example

The following example calculates the average salary of all employees in the hr.employees table:

SELECT AVG(salary) "Average" FROM employees;

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BFILENAME

Average

--------

6425

Analytic Example

The following example calculates, for each employee in the employees table, the average salary of the employees reporting to the same manager who were hired in the range just before through just after the employee:

SELECT manager_id, last_name, hire_date, salary,

AVG(salary) OVER (PARTITION BY manager_id ORDER BY hire_date ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS c_mavg

FROM employees;

BFILENAME

Syntax bfilename::=

BFILENAME ( ’ directory ’ , ’ filename ’ )

Purpose

BFILENAME returns a BFILE locator that is associated with a physical LOB binary file on the server’s file system.

■’directory’ is a database object that serves as an alias for a full path name on the server’s file system where the files are actually located

■’filename’ is the name of the file in the server’s file system

Functions 6-23

BFILENAME

You must create the directory object and associate a BFILE value with a physical file before you can use them as arguments to BFILENAME in a SQL or PL/SQL statement, DBMS_LOB package, or OCI operation.

You can use this function in two ways:

■In a DML statement to initialize a BFILE column

■In a programmatic interface to access BFILE data by assigning a value to the BFILE locator.

The directory argument is case sensitive. That is, you must ensure that you specify the directory object name exactly as it exists in the data dictionary. For example, if an "Admin" directory object was created using mixed case and a quoted identifier in the CREATE DIRECTORY statement, then when using the BFILENAME function you must refer to the directory object as ’Admin’. You must specify the filename argument according to the case and punctuation conventions for your operating system.

See Also:

■Oracle9i Application Developer’s Guide - Large Objects (LOBs) and Oracle Call Interface Programmer’s Guide for more information on LOBs and for examples of retrieving BFILE data

■CREATE DIRECTORY on page 13-49

Examples

The following example inserts a row into the sample table pm.print_media. The example uses the BFILENAME function to identify a binary file on the server’s file system:

CREATE DIRECTORY media_dir AS ’/demo/schema/product_media’;

INSERT INTO print_media (product_id, ad_id, ad_graphic) VALUES (3000, 31001,

bfilename(’MEDIA_DIR’, ’modem_comp_ad.gif’));

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