what is the difference between DBMS and RDBMS??

In DBMS Normalization process wille not be present and in RDBMS normalization process will be present to check the database table cosistency Muralidhran dharanmu@yahoo.com

what is the difference between primary key & foreign key?

Primary keys enforce entity integrity by uniquely identifying entity instances. Foreign keys enforce referential integrity by completing an association between two entities.

Difference between primary key and unique key ?

The column holding the primary key constraint cannot accept null values.whereas colum holding the unique constraint can accept null values assume that t3 is a table with two columns t1 having primary key constraint and t2 having unique constr

What is the difference between SQL, DDL, and DML?

Structured Query Language (SQL) is a language that provides an interface to relational database systems. In common usage SQL also encompasses DML (Data Manipulation Language), for INSERTs, UPDATEs, DELETEs and DDL (Data Definition Language),

what is the difference between TRUNCATE and DELETE command in SQL

Truncate command cannot be rolled back while Delete can be

find out the third highest salary?

select sal from emp where sal=(select min(sal) from emp where sal>(select min(sal) from emp where sal>(select min(sal) from emp);

How many different types of indexes we have in oracle?

We have mainly two different indexes . Implicit index and Explicit index. Explicit indexes are again of many types like simple index,unique index,Bitmap index,Functional index,Organisational index,cluster index.

What is Normalization ?

It is a technique for designing a database system. (BEST OF LUCK)

Can we create index on views?

An index cannot be defined on a view. Because view is virtual table, which consists of a subset of columns from one more tables. The Restrictions imposed on views are as follows: 1. A view can be created only in the current database. 2. A vi

What are joins..how many types of joins are there?

Joins are used to fetch a query on more than one table. You can broadly catagorize joins in to four types. 1. Equi Join 2.Non Equijoin 3.outer joins 4.self joins

In Oracle 9i what does "i" Stands for?

It is an advanced version of Oracle 8 for Internet-based applications. Hence here in Oracle9i i stands for Internet.

Query to get max and second max in oracle in one query ?

select distinct(a.colname) from table a where &n=(select count(distinct(b.colname)) from table b where a.colname<=b.colname); from this query u can find out Nth MAX in a one query eg select distinct(a.sal) from emp a where &n=(

What is schema?

schema is collection of objects (table,view,procedure,function.....)

Difference between sub query and nested query ?

Hi Friends, Query inside a query is called as Sub query. Sub query is also called as Nested Query. Thanks REDDY

What is the difference between column level constraints and table le

Column level constraints are applicable to that column only, whereas table level conatraints are used to define composite keys like primary key for the combination of two or more columns in a table

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