The NES Classic Edition is Nintendo’s miniaturized version of the groundbreaking NES, originally released in 1985. It comes pre-loaded with 30 games and it doesn’t […]
Database, Hacks, MongoDB, UNIX/Linux
Compile and install MongoDB on Raspberry PI
A 32 bit version of Raspbian is currently the most common OS that runs on a Raspberry PI. RPI 3 comes equipped with a 64 […]
Database, MongoDB
Join Array in MongoDB
Since version 3.2 you can use the $lookup to perform the equivalent of left outer joins in MongoDB. While you should try to design your […]
Database, MongoDB
When to use MongoDB $and Operator
On the surface, it seems like the $and operator is useless because it is implicitly applied when MongoDB processes each expression in the query. For […]
Database, MongoDB
MongoDB Aggregation to Custom Sort
While the MongoDB Aggregation Pipeline can be used to aggregate your data, it is definitely not limited to that and can be used to construct […]
Database, Java, MongoDB
MongoDB ClassCastException with new GridFS API
Starting with the MongoDB Java API 3.1 a new GridFS API has been added. It is available under the com.mongodb.client.gridfs package. If you are building […]
Database, MongoDB
Join Query in MongoDB
As a general rule, you should try to avoid joining as much as possible in MongoDB. While in traditional relational databases you try to avoid […]
Scripting, UNIX/Linux
Unzip multi-part archives in Linux
Although in Linux you can easily create multi-part zip files, unzipping them can be problematic. By using the -s argument in the zip command you […]
Database, Oracle, UNIX/Linux
Oracle 10g XE on Ubuntu/Debian Linux
Some time ago, Oracle removed the download links to Oracle 10g Express Edition (XE). If you need to do a new install of the Oracle […]
Scripting, UNIX/Linux
Schedule cron Job on First Sunday of the Month
When you need to schedule a Unix or Linux job in crontab to run on the first Sunday of the month, or any other weekday […]