Passing Parameters to Subprograms

PROCEDURE insert_anime_character(i_name IN VARCHAR2, i_series IN VARCHAR2, i_birthdate IN DATE, i_hair_color IN VARCHAR2 DEFAULT 'black')

positional notation
- follows the natural order of passing subprogram paramater values

EXEC insert_anime_character('Naruto', 'Naruto', SYSDATE, 'yellow');

named notation
- uses the "=>" as an association operator
- parameters could be passed in any order

mixed notation
- passing can start with positional then followed by named notation. However if you switch to named notation, you cannot revert back to positional notation. I'm assuming also that if you start with named notation you cannot switch to positional - because using named notation discards the positional data.


notes:
- parameters with default values can be skipped

PARAMETER MODES

3 types: IN (default), OUT, IN OUT

!! Avoid using OUT and IN OUT for functions. f(x)s should only return one value.

IN (mode)
- acts like a constant inside the subprogram, which in effect you cannot modify it
- the ONLY mode that can be assigned a DEFAULT value
- can be a constant, literal, initialized variable or expression

OUT (mode)
- in contrast to IN mode, you can use OUT parameters as a local variable: and change its values.
- OUT parameters MUST BE VARIABLES

- the initial value of an OUT parameter is discarded when it enters the subprogram. However you can override this by specifying the compiler hint NOCOPY.
- the idea is to modify it inside the subprogram and it will carry OUT the value to the caller subprogram
- OUT parameters are initialized to NULL; therefore you cannot assign a NOT NULL configured subtype to an OUT parameter

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well I used it immediately and converted some of my functions to procedures for multi-value RETURN

(TODO: IN OUT)