n this chapter, you’ll learn how to create users, databases, tables, indexes, constraints, sequences, and views in Oracle and MySQL databases. The chapter is organized by the following topics:

  Users

  Databases

  Tables

  Indexes

Users are synonymous with schemas in an Oracle database, but they are distinct from databases in MySQL databases. A database or schema is a private work area, but it is also a container of tables. Tables are two-dimensional containers of data, and views are logical filters to access subsets or supersets of tables. Sequences are structures that support automatic numbering of ID columns for tables. Sequences are described and explained in the “Tables” section in this chapter, because although they’re independent data structures in an Oracle database, they’re properties of tables in the MySQL database. Constraints are structures that restrict the type of data you can put in tables. Tables and constraints are also discussed in the “Tables” section.