Philipp Salvisberg’s Blog
Database-centric development
2012-12-24
From time to time a customer asks me how to join multiple tables with temporal intervals (e.g. defined by two columns such as valid_from and valid_to per row). The solution is quite simple if you may limit your query to a certain point in time like now, yesterday or similar. Such a […]
2012-12-23
From time to time I’m asked to aggregate strings from multiple records into a single column using SQL. Here’s an example, showing a comma-separated list of ordered employee names per department based on the famous EMP and DEPT tables. Oracle introduced the aggregate function LISTAGG for that purpose in 11.2. If you […]
2012-12-02
I’ve just bought a Sony DSC RX100 camera with an Apple iPad Camera Connection Kit. The kit contains an USB adapter and a SD Card adapter. I intend to copy photos to my iPad for review and backup purposes during my holidays. My son argued that the SD card adapter must be […]
2011-10-12
Last week I had a talk at Oracle’s OpenWorld 2011 titled Modern PL/SQL Code Checking and Dependency Analysis. The problem I described in chapter 4 was to find all view columns using the column UNIT_COST of the table COSTS in the SH schema. Other usages of this column (e.g. in where or […]
2011-09-28
I’ve released the last version of StartUp in December 1999 and the last version of Crypto in March 2002. That’s quite a long time ago. I don’t plan to work with Symbian OS anymore. If you need one of these programs (source or ARM or WINS binary) just drop me an email […]