Introduction of Apache Hive

What is Apache Hive?
Apache Hive is a Data warehouse system which is built to work on Hadoop. It is used to querying and managing large datasets residing in distributed storage. Before becoming a open source project of Apache Hadoop, Hive was originated in Facebook. It provides a mechanism to project structure onto the data in Hadoop and to query that data using a SQL-like language called HiveQL.

What is HQL?
Hive defines a simple SQL-like query language to querying and managing large datasets called Hive-QL ( HQL ). It’s easy to use if you’re familiar with SQL Language. Hive allows programmers who are familiar with the language to write the custom MapReduce framework to perform more sophisticated analysis.

Uses of Hive:

1. The Apache Hive distributed storage.
2. Hive provides tools to enable easy data extract/transform/load (ETL).
3. It provides the structure on a variety of data formats.

Data Definition Language (DDL )

DDL statements are used to build and modify the tables and other objects in the database.
Example :CREATE, DROP, TRUNCATE, ALTER, SHOW, DESCRIBE Statements.

Data Manipulation Language (DML )

DML statements are used to retrieve, store, modify, delete, insert and update data in the database.
Example :LOAD, INSERT Statements.