| You have learned a little about database objects in general, but have specifically learned about the table. The table is the simplest form of data storage in a relational database. Tables contain groups of logical information, such as employee, customer, or product information. A table is composed of various columns , with each column having attributes; those attributes mainly consist of data types and constraints, such as NOT NULL values, primary keys, foreign keys, and unique values. You learned the CREATE TABLE command and options, such as storage parameters, that may be available with this command. You have also learned how to modify the structure of existing tables using the ALTER TABLE command. Although the process of managing database tables may not be the most basic process in SQL, it is our philosophy that if you first learn the structure and nature of tables, you more easily grasp the concept of accessing the tables, whether through data manipulation operations or database queries. In later hours, you learn about the management of other objects in SQL, such as indexes on tables and views.  |
