Category Archives: sql

SQL – Clustered Index Table of content An index in a database is a data structure that helps to improve the speed of retrieving specific data from tables and views. Data in a table is stored in the form of an unordered data structure called a “Heap”, where rows are placed without any specific order. […]

SQL – Unique Indexes Table of content SQL Unique Indexes The SQL Unique Index ensures that no two rows in the indexed columns of a table have the same values (no duplicate values allowed). A unique index can be created on one or more columns of a table using the CREATE UNIQUE INDEX statement in […]

SQL – Non-Clustered Index Table of content SQL Non-Clustered Indexes The SQL Non-Clustered index is similar to the Clustered index. When defined on a column, it creates a special table which contains the copy of indexed columns along with a pointer that refers to the location of the actual data in the table. However, unlike […]