Indexes are optional data structures associated with Database tables. Indexes are logically & physically independent of the data in the associated table. They are independent database objects created to reduce disk I/O & speed up execution of SQL statements on a table. We can create many indexes on a table given that each index points to different column (in case of a single column) or unique combination of columns from a table. All Indexes offer complementary performance functionalities based on their structure: B-Tree indexes : B-Tree Indexes are stored as a conventional binary data structure in the database. Each branch node contains a key prefix to make a direction between two keys. Each Leaf Node is at same depth from the branch node and contain complete key value for each row & ROWID. Features : All leaf blocks of the tree are at same depth, resulting same performance for retrieval of any record from the indexed table. B-Trees are stay balanced automatically. Exc...
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