September 2012
Intermediate to advanced
350 pages
9h 46m
English
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Chapter 4. HiveQL: Data Definition
HiveQL is the Hive query language. Like all SQL dialects in widespread use, it doesn’t fully conform to any particular revision of the ANSI SQL standard. It is perhaps closest to MySQL’s dialect, but with significant differences. Hive offers no support for row-level inserts, updates, and deletes. Hive doesn’t support transactions. Hive adds extensions to provide better performance in the context of Hadoop and to integrate with custom extensions and even external programs.
Still, much of HiveQL will be familiar. This chapter and the ones that follow discuss the features of HiveQL using representative examples. In some cases, we will briefly mention details for completeness, then explore them more fully in later chapters.
This chapter starts with the so-called data definition language parts of HiveQL, which are used for creating, altering, and dropping databases, tables, views, functions, and indexes. We’ll discuss databases and tables in this chapter, deferring the discussion of views until Chapter 7, indexes until Chapter 8, and functions until Chapter 13.
We’ll also discuss the SHOW and
DESCRIBE commands for listing and
describing items as we go.
Subsequent chapters explore the data manipulation language parts of HiveQL that are used to put data into Hive tables and to extract data to the filesystem, and how to explore and manipulate data with queries, grouping, filtering, joining, etc.
Databases in Hive
The Hive concept of a database is essentially ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.