SAP HANA is a cutting-edge in-memory database platform that supports advanced analytical processing. One powerful feature it offers is Full-Text Search capability, which allows users to perform efficient text-based searches within large volumes of unstructured or semi-structured data. Full-text indexes play a key role in enabling these searches by optimizing how text data is stored and queried.
This article explores the concept of full-text indexes in SAP HANA, how to create and manage them, and best practices to leverage their power effectively.
A full-text index in SAP HANA is a specialized index structure designed to speed up searches within textual data. Unlike traditional indexes that operate on numeric or exact-match data, full-text indexes support:
This makes full-text indexes ideal for scenarios such as document search, product catalogs, customer feedback analysis, and more.
Full-text indexes can be created on one or more columns that contain textual data, such as VARCHAR, NVARCHAR, or CLOB data types.
The syntax for creating a full-text index is as follows:
CREATE FULLTEXT INDEX <index_name> ON <schema>.<table> (<column1>, <column2>, ...)
Example:
CREATE FULLTEXT INDEX ft_index_products ON SALES.PRODUCTS (DESCRIPTION, FEATURES);
This command creates a full-text index named ft_index_products on the DESCRIPTION and FEATURES columns of the PRODUCTS table.
Once the full-text index is created and populated, you can perform efficient text searches using SQL functions such as:
CONTAINSCONTAINS_TABLESELECT PRODUCT_ID, DESCRIPTION
FROM SALES.PRODUCTS
WHERE CONTAINS(DESCRIPTION, 'wireless headset');
This query retrieves products whose description contains the phrase “wireless headset”.
SELECT p.PRODUCT_ID, p.DESCRIPTION, ft.RANK
FROM SALES.PRODUCTS p
JOIN CONTAINS_TABLE(SALES.PRODUCTS, DESCRIPTION, 'wireless headset') AS ft
ON p.PRODUCT_ID = ft.KEY
ORDER BY ft.RANK DESC;
This query returns matching rows with a relevance rank, ordering the most relevant results first.
Full-text indexes need to be rebuilt or updated after data changes to ensure search accuracy. SAP HANA handles this automatically for most cases but manual rebuilds can be triggered:
ALTER FULLTEXT INDEX ft_index_products REBUILD;
If an index is no longer required, it can be dropped:
DROP FULLTEXT INDEX ft_index_products ON SALES.PRODUCTS;
Full-text indexes in SAP HANA empower businesses to perform fast and flexible text searches over large datasets, unlocking insights hidden in unstructured data. Proper creation, usage, and management of these indexes are crucial to harness their full potential.
Understanding how to work with full-text indexes will enable SAP HANA users and administrators to build more powerful search-driven applications and analytical scenarios.