On 2023-01-14 06:32:03 +0100, Peter J. Holzer wrote:
> Oracle has a function which returns the internal representation of a
> value as a series of (decimal) byte values. Back in the days when I was
> new to Oracle I used this to figure out how Oracle stores NUMBER, but
> now I've forgotten the name of the function. Maybe adding something like
> this to PostgreSQL would be worthwhile?
Found it:
| DUMP
|
| Syntax
|
| DUMP(expr[, return_fmt [, start_position [, length ] ] ])
|
| Purpose
|
| DUMP returns a VARCHAR2 value containing the data type code, length in
| bytes, and internal representation of expr. The returned result is
| always in the database character set. For the data type corresponding to
| each code, see Table 2-1, "Built-in Data Type Summary".
|
| The argument return_fmt specifies the format of the return value and can
| have any of the following values:
|
| * 8 returns result in octal notation.
|
| * 10 returns result in decimal notation.
|
| * 16 returns result in hexadecimal notation.
|
| * 17 returns each byte printed as a character if and only if it can be
| interpreted as a printable character in the character set of the
| compiler—typically ASCII or EBCDIC. Some ASCII control characters
| may be printed in the form ^X as well. Otherwise the character is
| printed in hexadecimal notation. All NLS parameters are ignored. Do
| not depend on any particular output format for DUMP with return_fmt
| 17.
|
| By default, the return value contains no character set information. To
| retrieve the character set name of expr, add 1000 to any of the
| preceding format values. For example, a return_fmt of 1008 returns the
| result in octal and provides the character set name of expr.
|
| The arguments start_position and length combine to determine which
| portion of the internal representation to return. The default is to
| return the entire internal representation in decimal notation.
|
| If expr is null, then this function returns NULL.
|
| This function does not support CLOB data directly. However, CLOBs can be
| passed in as arguments through implicit data conversion.
hp
--
_ | Peter J. Holzer | Story must make more sense than reality.
|_|_) | |
| | | hjp@hjp.at | -- Charles Stross, "Creative writing
__/ | http://www.hjp.at/ | challenge!"
