Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "In PostgreSQL 9.6, the utility pg_Standby is no longer required, as many of its features are now performed directly by the server."

A block of code is set as follows:

CREATE USER repuser
       SUPERUSER
       LOGIN
       CONNECTION LIMIT 1
       ENCRYPTED PASSWORD 'changeme';

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

SELECT *FROM mytable
 WHERE  (col1, col2, … ,colN) IN
 (SELECT col1, col2, … ,colN
  FROM mytable
  GROUP BY col1, col2, … ,colN
  HAVING count(*) > 1);

Any command-line input or output is written as follows:

$ postgres --single -D /full/path/to/datadir postgres

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: " The Query tool has a good looking visual explain feature as well as a Graphical Query Builder, as shown in the following screenshot".