Oracle already provides an automatic exclusive locking mechanism for the rows you want to update. However you can override it to customize the performance (for example, if you need consistent data and/or exclusive access for the duration of a whole and more complex transaction). When your application requires consistent data for the duration of the […]
Yesterday I discovered the powerful hibernate check constraint (@org.hibernate.annotations.Check) , which can be directly added in your entity class like this: Unfortunately, as you can read in the official MySQL docs, “the CHECK clause is parsed but ignored by all storage engines”. Yesterday I found out that MySql 5.X doesn´t support the SQL CHECK constraint. […]
I’m currently working on my Master degree thesis and I’m projecting a demo database about a Mammography archive. The purpose is providing an archive, whose clinical cases can be consulted on a portal page by a user interface. I must create a database for a Liferay portal. Liferay is a very powerful opensouce CMS / […]
You can download “Perl Scripting for SQLite”. It’s a pdf of the slides I’ve made for the “Linux day 2011” in my hometown. Have fun!
Let’s analyze the following perl scripta “cinema.pl”, to create and populate a simple database about movies, and “query_hollywood.pl” to execute a simple SELECT-FROM-WHERE query on it. —————————————cinema.pl———————————————————— #!/usr/bin/perl -w use DBI; use strict; # CONFIG VARIABLES my $platform = “SQLite”; my $database = “hollywood.db”; my $host = “localhost”; my $port = “3306”; my $user = […]
Let’s go on mastering our sqlite3 knowledge. SQLite database is really just a file: a backup it’s as simple as copying one file. The .dump command shows information about all the changes performed onto the database. Less pieces of information to the hidden file can be found in your home/user typing: $ ~/.sqlite_history. $ sqlite3 […]
Sqlite is useful to create a database (one file, .db extension) used to store configuration data, used Miicrosoft, Skype, Banshee… Smart Phone applications…. The file extension .db stands for a whole database: it’s made by the software C library called Sqlite… This is a great opportunity to learn about SQLITE and the Perl scripting languages… […]