Description

Programming languages come and go constantly, and very few languages in use today
have roots going back more than a decade or so. Some examples are COBOL, which
is still used quite heavily in mainframe environments; Java, which was born in the
mid-1990s and has become one of the most popular programming languages; and C,
which is still quite popular for operating systems and server development and for
embedded systems. In the database arena, we have SQL, whose roots go all the way
back to the 1970s.
SQL was initially created to be the language for generating, manipulating, and retriev‐
ing data from relational databases, which have been around for more than 40 years.
Over the past decade or so, however, other data platforms such as Hadoop, Spark, and
NoSQL have gained a great deal of traction, eating away at the relational database
market. As will be discussed in the last few chapters of this book, however, the SQL
language has been evolving to facilitate the retrieval of data from various platforms,
regardless of whether the data is stored in tables, documents, or flat files.