26Introduction to SQL
Eventually, you (or someone else) must build the database that you've designed. Also at some point, someone will probably want to actually use the database you've spent so much time designing.
Structured Query Language (SQL, sometimes pronounced “sequel”) is a database language that includes commands that let you build, modify, and manipulate relational databases. Many database tools use SQL either directly or behind the scenes to create and manipulate the database. For example, Figure 26.1 shows how the pgAdmin tool uses SQL to define the order_items table used in Chapters 18 and 19, which cover PostgreSQL.
Because SQL is standardized, many database management tools use it to control relational databases. They use buttons, drop-down menus, check boxes, and other user interface controls to let you design a database interactively, and then they send SQL code to the database engine to do the work.
In addition to using database tools to generate your SQL code, you can write that code yourself, which lets you create and modify the database as needed. It also lets you add data to put the database in a known state for testing. In fact, SQL is so useful for building databases that it's the topic of the next chapter.
Get Beginning Database Design Solutions, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
