Introducing SQL

Structured Query Language (SQL and often pronounced "sequ-el") provides a common language for querying and manipulating data in relational databases. While there are a few differences, SQL mostly works the same in relational database systems such as Oracle, SQL Server, MySQL, and H2.

The first thing you need to do is to create a table. To do so, use the CREATE TABLE SQL command. To create a table, you must provide the name of the table, the names and types of the columns, and any constraints.

Exercise 2: Creating the customer Table

Use the SQL CREATE TABLE command to create a customer table. It should contain the customer ID and the users' first and last names.

1. Enter the following SQL commands in the upper-right input pane:

   CREATE TABLE IF NOT EXISTS customer
   (
   CUSTOMER_ID long,
   USERNAME varchar(255),
   FIRST_NAME varchar(255),
   LAST_NAME varchar(255),
   UNIQUE(USERNAME),
   PRIMARY KEY (CUSTOMER_ID)
   );

2. After entering the SQL command, click...