What is a View?
Views are similar to tables, which are generated based on the requirements.
- We can save any result set data as a view in Hive
- Usage is similar to as views used in SQL
- All type of DML operations can be performed on a view
Creation of View:
Syntax:
Create VIEW <VIEWNAME> AS SELECT
Example:
Hive>Create VIEW Sample_ViewAS SELECT * FROM employees WHERE salary>25000
In this example, we are creating view Sample_View where it will display all the row values with salary field greater than 25000.
What is Index?
Indexes are pointers to particular column name of a table.
- The user has to manually define the index
- Wherever we are creating index, it means that we are creating pointer to particular column name of table
- Any Changes made to the column present in tables are stored using the index value created on the column name.
Syntax:
Create INDEX <INDEX_NAME> ON TABLE < TABLE_NAME(column names)>
Example:
Create INDEX sample_Index ON TABLE guruhive_internaltable(id)
Here we are creating index on table guruhive_internaltable for column name id.
