Generate Entity Relationship Diagrams from a SQL Script.

Sometimes, just occasionally, you find yourself as a DBA on a site where, for some strange and unknown reason, you don’t have an Entity Relationship Diagram (ERD) for the database that you are working on. You could use a tool such as Toad, or SQL*Plus (or even, SQL Developer – if you must) to generate a list of referential integrity constraints. There has to be a better way. Continue reading Generate Entity Relationship Diagrams from a SQL Script.

Snorkelling in the Oracle Listener Logs.

(Snorkelling is not quite as in depth as a “deep dive”!)

Attempting to parse a listener.log will probably bend your brain, but I needed to do it recently to determine which unique servers and/or desktops and/or application servers were still connecting to a database prior to that database going down for maintenance. This was an exercise in confirming that the documentation we have, is correct.

Continue reading Snorkelling in the Oracle Listener Logs.

Arduino Nano – Cannot Upload Sketches after Board Upgrade to 1.6.21

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My Arduino Nano started to refuse to upload sketches after I upgraded the boards library to version 1.6.21 from 1.6.20. All I got was this:

...
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
...

Repeat 100 times!

After reverting back to the previous boards library, version 1.6.20, everything worked. I upgraded and everything stopped working.

The solution, from the arcduino.cc forums, is simple:

Tools -> Processor -> ATmega328P (Old Bootloader)

Read the forum thread at https://forum.arduino.cc/index.php?topic=532983.0 if you wish. I’m just noting this here for my own reference and definitely not claiming any credit.

Using FUSE to Mount an SSH Folder Locally

I have recently come across a pretty nifty Linux utility that allows me to mount a remote filesystem on an SSH server, locally and without requiring root privileges to do so. The remote filesystem happens to be where my backups are located, so that’s going to be useful for making and restoring backups! Continue reading Using FUSE to Mount an SSH Folder Locally

FLAC to MP3 as Easy as Pie!

I have ripped all my music, well most of it, to FLAC for the quality aspect. Sometimes though, I need to convert to MP3 for some of the lesser audio players out there that I might have to use from time to time.

I have recently come across a pretty nifty (Linux) way to do this, without having to cope with having duplicate files in FLAC and MP3 formats on my hard drives. Continue reading FLAC to MP3 as Easy as Pie!

Dropping Temporary Tables (With Bonus, Broken Check Constraints!)

I found a broken check constraint, one that simply wouldn’t work, on a database. It was created as:

... CHECK(COLUMN_NAME IN ('Y','N',NULL)) ;

Try it yourself, it doesn’t work! Anyway, I needed to find if there were any other check constraints broken in this manner, so I did the following:

Continue reading Dropping Temporary Tables (With Bonus, Broken Check Constraints!)