10.What is indexing what is the role of indexing in database

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Indexing is a technique used in databases to improve the performance of queries by creating a data structure that allows for faster data retrieval.

Indexing creates a separate data structure that contains a subset of the data in the database, organized in a way that allows for efficient searching and retrieval.
Indexes are created on one or more columns of a table and can be used to quickly locate data based on the values in those columns.
By using indexes, database systems can avoid scanning the entire table and instead perform a more targeted search, resulting in faster query execution.
Indexes can be created on both single columns and multiple columns, and different types of indexes (such as B-tree, bitmap, or hash indexes) can be used depending on the specific requirements of the database and queries.
However, indexing also has some trade-offs, as it requires additional storage space and can slow down data modification operations (such as inserts, updates, and deletes) as the indexes need to be maintained.
Overall, indexing plays a crucial role in improving the performance of database queries by enabling faster data retrieval and reducing the need for full table scans.

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