What is clustered and non-clustered indexes?
Answers were Sorted based on User's Feedback
Answer / thangaprabu.n
Apart From above answer,One table Contain only 1 Cluster
index and 249 Non-Cluster Indexes
| Is This Answer Correct ? | 9 Yes | 2 No |
Answer / shubhi
There are clustered and nonclustered indexes. A clustered
index is a special type of index that reorders the way
records in the table are physically stored. Therefore table
can have only one clustered index. The leaf nodes of a
clustered index contain the data pages.
A nonclustered index is a special type of index in which
the logical order of the index does not match the physical
stored order of the rows on disk. The leaf node of a
nonclustered index does not consist of the data pages.
Instead, the leaf nodes contain index rows.
| Is This Answer Correct ? | 9 Yes | 3 No |
Answer / ganesh sial
both index are stored physically but cluster index is create block of key value which more helps to like join,hash condition,more reliable to parent child relation ship
ex:- deptno is primary key for dept table, its create cluster index,
when write query of join like
select a.empno,a.deptno,b.loc from emp a,dept b where a.deptno=b.deptno
this case the cluster index helps to better perfomance
| Is This Answer Correct ? | 1 Yes | 0 No |
What are the ddl commands?
What are the basic sql commands?
What are primary key and foreign key and how they work?
What is a unique key?
What is a dirty read sql?
how to retrieve only duplicate values in a table
What is the use of sql trace?
Temporary table vs Table variable in sql server?
How collections are improve the performance?
How to prepare for oracle pl sql certification?
write a query to delete similar records in different tables with same structure
Does truncate remove indexes?
Oracle (3259)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)