Let's say that I have a company with items, each stored in a database with a unique ID as a primary key. In addition to that, I also have a database of customers. I want to store orders from customers ...

The optimizer is the heart and soul of a relational DBMS. It analyzes SQL statements and determines the most efficient access plan for satisfying each statement. The optimizer accomplishes this by ...

Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

When object-oriented programming languages began to be used in enterprise applications, designers had problems fitting the object-oriented model with the relational model. In the object-oriented model ...