Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "The database username will be postgres."

A block of code is set as follows:

SELECT 
id_order
, single_item_orders->>'id_menu' as id_menu
, single_item_orders->>'count' as item_count
FROM 
(
    SELECT 
    id_order
    , json_array_elements(order_description) as
single_item_orders
    FROM 
        orders
) each_order 

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "The dataset is based on a fictional e-commerce business called Pickles and Pies."

Tips or important notes

Appear like this.