The concept of a table in Hive is very similar to the table in the relational database. Each table maps to a directory, which is under /user/hive/warehouse by default in HDFS. For example, /user/hive/warehouse/employee is created for the employee table. All the data in the table is stored in this hive user-manageable directory (full permission). This kind of table is called an internal, or managed, table. When data is already stored in HDFS, an external table can be created to describe the data. It is called external because the data in the external table is specified in the LOCATION property rather than the default warehouse directory. When keeping data in the internal tables, the table fully manages the data in it. When an internal table is dropped, its data is deleted together. However, when an external table is dropped, the data is not deleted. It is quite common to...
Apache Hive Essentials. - Second Edition
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Apache Hive Essentials. - Second Edition
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Overview of this book
In this book, we prepare you for your journey into big data by frstly introducing you to backgrounds in the big data domain, alongwith the process of setting up and getting familiar with your Hive working environment.
Next, the book guides you through discovering and transforming the values of big data with the help of examples. It also hones your skills in using the Hive language in an effcient manner. Toward the end, the book focuses on advanced topics, such as performance, security, and extensions in Hive, which will guide you on exciting adventures on this worthwhile big data journey.
By the end of the book, you will be familiar with Hive and able to work effeciently to find solutions to big data problems
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Current Title:
Apache Hive Essentials. - Second Edition
Table of Contents (12 chapters)
Preface
Free Chapter
Overview of Big Data and Hive
Setting Up the Hive Environment
Data Definition and Description
Data Correlation and Scope
Data Manipulation
Data Aggregation and Sampling
Performance Considerations
Extensibility Considerations
Security Considerations
Working with Other Tools
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