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. |_|_) | | | | | h...@hjp.at | -- Charles Stross, "Creative writing __/ | http://www.hjp.at/ | challenge!"
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