In this chapter, we will discuss basic SQL commands for PostgreSQL; these are Data Definition Language (DDL) commands and Data Manipulation Language (DML) commands. In basic terms, DDL commands are used to manage databases and tables, and DML commands are used to insert, delete, update, and select data inside databases. In this chapter, we will also discuss the psql environment, which refers to the interactive terminal for working with PostgreSQL. psql can be described as PostgreSQL's shell environment; it is the gate we have to go through in order to start writing commands natively in PostgreSQL. We have to remember that psql is always present in any PostgreSQL installation we work with. psql is a powerful environment in which to manage our data and our databases.
Basic statements and psql are therefore the foundations on which we will build our knowledge...
