introduction to databases introduction there are several different types of database system in common use today including object databasesnosql databases and (probably the most commonrelational databases this focusses on relational databases as typified by database systems such as oraclemicrosoft sql server and mysql the database we will use in this book is mysql what is databasea database is essentially way to store and retrieve data typicallythere is some form of query language used with the database to help select the information to retrieve such as sql or structured query language in most cases there is structure defined that is used to hold the data (although this is not true of the newer nosql or non-relational unstructured databases such as couchdb or mongodbin relational database the data is held in tableswhere the columns define the properties or attributes of the data and each row defines the actual values being heldfor example(cspringer nature switzerland ag huntadvanced guide to python programmingundergraduate topics in computer science