The CREATE FULLTEXT INDEX statement in SQL is used to create a full-text index on a table in order to support full-text searches on text columns. This functionality is supported by various database management systems (DBMS), including MySQL and SQL Server, but the syntax and capabilities can differ between systems.
MySQL
In MySQL, the CREATE FULLTEXT INDEX statement can be used as follows:
1. Basic Syntax:
CREATE FULLTEXT INDEX index_name ON table_name(column1, column2, ...);
- index_name: The name you want to give to your index.
- table_name: The name of the table on which you are creating the index.
- column1, column2, ...: The columns to include in the full-text index.
2. Example:
CREATE FULLTEXT INDEX ft_index ON articles(title, body);
In this example, a full-text index named ft_index is created on the title and body columns of the articles table.
3. Search Using Full-Text Index:
After creating the Full-Text Index, you can use MATCH() and AGAINST() in your SELECT queries to perform full-text searches:
SELECT * FROM articles
WHERE MATCH(title, body) AGAINST('search term' IN NATURAL LANGUAGE MODE);
SQL Server
In SQL Server, the process is slightly different:
1. Create a Full-Text Catalog (if it does not exist):
CREATE FULLTEXT CATALOG catalog_name AS DEFAULT;
2. Create a Full-Text Index:
CREATE FULLTEXT INDEX ON table_name(column1)
KEY INDEX index_name ON catalog_name;
- table_name: The name of the table.
- column1: The column on which to create the full-text index.
- index_name: A unique index name on the table that will be used as the key for the full-text index.
- catalog_name: The name of the full-text catalog where the index will be stored.
3. Example:
Suppose you have a table called Documents:
CREATE FULLTEXT CATALOG FT_Catalog AS DEFAULT;
CREATE FULLTEXT INDEX ON Documents(Content)
KEY INDEX PK_Documents ON FT_Catalog;
In this example, a Full-Text Index is created for the Content column of the Documents table using the primary key index PK_Documents.
4. Search Using Full-Text Index:
After setting up the full-text index, you can perform full-text searches using the CONTAINS or FREETEXT functions:
SELECT * FROM Documents
WHERE CONTAINS(Content, 'search term');
Summary
The CREATE FULLTEXT INDEX statement allows you to efficiently search large text-based columns in your database. Remember that its implementation and syntax can vary significantly between MySQL, SQL Server, and other systems, so always check the documentation for your specific DBMS to understand the exact capabilities and limitations.