Indexes in database are used to accelerate the data retrieval process. Queries like SELECT and WHERE clauses can be accelerated using indexes but they ultimately slow down UPDATE and INSERT statements. Index creation has no effect on the data present in a table. The CREATE INDEX statement is used create an index; CREATE INDEX statement […]
What is Bitmap Index?
Bitmap index in a Oracle database is special type of database index which is used to reduce cardinality of columns. The columns with lower cardinality value will result in result in relatively unique values. Consider that there is a column called binary digits; this column will have only two values namely 0 and 1. The […]
SQL: Clustered vs non clustered Index
An index in SQL may be defined as a structure linked with a particular table and is stored on the disk, mainly created to enhance the speed of the retrieval of data. The key for an index in SQL is created from one or more than one column present in a particular table or even […]
SQL questions: What is an index?
An Index in SQL may be defined as the secondary database object which is connected to a specific table to enhance the process of retrieval of the associated rows from that particular table. It can be defined for a specific single column or for multiple columns. We can also view an index of SQL as […]