Grid without X

We just received new PCs. Brand new with XP. Nice? Let’s see! As usual, I started my Exceed and logged on my AIX server. I tried to start the Grid Control Engine (opmn). Hard luck. Failed to start OC4J instance 🙁 The first problem is, when I installed the Grid, my old workstation DISPLAY name… Continue reading Grid without X

Recursive SQL

One of the most common school exercice about recursion is the factorial. Guess what, I am going to do it in sql with hierarchies! I use the following ln property : x1*…*xn = exp(ln(x1)+..+ln(xn))) Ok, here it is SQL> select n, (select exp(sum(ln(level))) from dual connect by level

Get disk space

I just read today on sun.com that checking disk space in java will be platform independent in the java.io.File class before 2007, add a few years until it is integrated in Oracle. But I cannot wait that long, so I decided to write my own code with “df” on my AIX box. Ok, let’s do… Continue reading Get disk space

One example about hierarchies

Today morning I just received a question from a friend where I used hierarchies : > Let’s assume a couple of persons have bought some cakes togeher and they want to eat it: > > Create table cake_owners > (owner# number, > cake# number, > constraint cake_pk primary key (owner#,cake#) > using index); > >… Continue reading One example about hierarchies

Hierarchical queries

The typical hierarchical query is you want to select your boss, and the boss of your boss, etc. It could look like select prior ename ename, ename mgr from emp connect by prior mgr=empno start with ename=’SCOTT’; SCOTT SCOTT JONES JONES KING I start with Scott and the hierarchy is built. I can use the… Continue reading Hierarchical queries