What is indexing in database ?
What is Indexing in Database ?
- Indexing is the One of the ways that will optimize the database searching and accessing is having indexes on the columns that access the data in a database table.
- An index object is created in database with the column/columns value that are mentioned while creating the index.
- The value in the index holds the row id of the physical data location in the database which helps for fast data retrieval of the corresponding rows.
What is Indexing Database
Types Of Index
- Clustered indexes define the physical sorting of a database table’s rows in the storage media. For this reason, each database table may have only one clustered index.
- Non-clustered indexes are created outside of the database table and contain a sorted list of references to the table itself.
Cluster & Non Clustered Index
Advantages of Indexes
- Indexes their use in queries usually results in much better performance.
- Make it possible to quickly retrieve (fetch) data.
- They can be used for sorting. A post-fetch-sort operation can be eliminated.
- Unique indexes guarantee uniquely identifiable records in the database.
Disadvantages of Indexes
- They decrease performance on inserts, updates, and deletes.
- It will take up space (this increases with the number of fields used and the length of the fields).
- Some databases will monocase values in fields that are indexed.