This chapter has looked at the means by which Julia interacts with data held in databases and data stores. Until recently, the great majority of databases conformed to the relational model, the so-called SQL database.

However, the rapid explosion in data volumes accompanying the big data revolution has led to the introduction of a range of databases based on other data models. These are normally grouped under the heading NoSQL and are categorized as key-value, document, and graphic databases. With such a large field to cover, we identified some definitive examples in each category.

Julia's approaches are largely specific to each individual case, and the appropriate packages and methods for loading, maintaining, and querying the different types of databases have been presented.

In the next chapter, we will discuss working with various networked systems. We will look at developing Internet servers, working with web sockets, and messaging via e-mail, SMS, and Twitter. Finally, we will...