I am glad to announce about “SQL Fundamentals”, a new course available for free at www.abelski.com. SQL is a structured programming language we can use to query, update and manage relational databases. This course overviews SQL fundamental topics and provides with the required knowledge to develop software applications that use a relational database. SQL stands for Structured Query Language. Registration is required in order to take this course. The registration is free.
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.