Building Java Enterprise Applications

Databases

With the general data model done, we can now begin to cover the implementation details. In other words, we are finally through all the high-level talk and into the meat! In this section, you’ll pick apart the data model and determine what portions belong in a database. You can then look at actually creating the tables, rows, columns, and keys that you’ll need in the database to represent the data. Once you’ve accomplished that, we’ll spend the next section looking at directory servers and performing the same task for the data that belongs in that physical medium.

Of course, the language of choice for databases is the Structured Query Language (SQL), and we’ll use it to deal with databases here. Most databases now come with tools to make the creation of data structures simple; these are usually graphical and present a visual means of creating data structures. Additionally, a number of third- party tools are good for this sort of task (like SQL Navigator, already mentioned in Chapter 1). I’ll focus on using pure SQL in this section, so the code will work on any database, on any platform, without you having to learn or buy a specific vendor’s tool.

Vendor-Specific SQL

The acronym SQL is used fairly generically in the text. When referenced, this implies the use of ANSI-92 SQL. However, most database vendors provide extensions to SQL, and often even additional data types. While these additional constructs can improve performance on a specific database, it makes the resulting ...