Home

Product Quickcode Generator

How to generate a Base36 quick code sequence using the SHA2 hash

On a 'slowish' 2GHz machine it can generate 20,000 quickcodes per minute. The spread of the resulting quickcodes is near-perfectly even, which means that substrings of the quickcode can be used to construct a hashed directory tree for holding, for example, the huge amount of product image files associated with a product catalog. Using a hashed directory tree is a quick and efficient method to host millions of separate files for quick, random access, as most file systems only perform optimally with less than 1,000 contained in a directory

This deterministic techique uses a hash of the sequential Integer Id of an item to generate a typical product quickcode for it, as found in many shopping catalogues. Example of how a quickcode is generated from its primary key integer Id:

1 => 8M9LFLN2
2 => HZ40H3K0
3 => 02LUJYQ2
etc..

You can download the Base36 Quickcode Generator test script, which demonstrates an implementation in Perl and MySQL.

Oracle DBMS_PIPE - why you should abandon it

A classical method of getting Oracle-based processes communicating with the outside world is by using the DBMS_PIPE package: Typically, we write to a pipe from an Oracle PL/SQL-based process, and then we continuously run an asynchronous Oracle PL/SQL process which reads the pipe and processes what it reads. A common use of DBMS_PIPE is for debugging, logging and launching external processes.

Oracle External Procedures

It is possible to call O/S commands or third-party programs from within SQL or PL/SQL with external procedures. This guide describes how to build, install and use such an ExtProc and shows an exploit on how to grant yourself Oracle sysdba rights. Think of an ExtProc as an Oracle root kit.