Logical Indexes
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In a database, a logical index is an index structure that replaces the usual pointers to physical table blocks with the actual primary key values of the rows in the table. In traditional index structures like B-trees or B+ trees, each index entry typically contains a pointer to the corresponding data block where the indexed row resides. However, in a logical index, these pointers are replaced with the primary key values of the rows. |
Logical indexes are always secondary indexes, meaning they are additional indexes created on columns other than the primary key of the table. A primary index is automatically created on the primary key of the table by the database management system (DBMS) itself. So, a logical index is a secondary index that complements the primary index.
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