What is the difference between oracle,sql and sql server ?
why you need indexing ? where that is stroed and what you mean by schema object? For what purpose we are using view?
We cant create an Index on Index.. Index is stoed in user_index table.Every object that has been created on Schema is Schema Object like Table,View etc.If we want to share the particular data to various users we have to use the virtual table for the Base table...So tht is a view.
indexing is used for faster search or to retrieve data faster from various table. Schema containing set of tables, basically schema means logical separation of the database. View is crated for faster retrieval of data. It's customized virtual table. we can create a single view of multiple tables. Only the drawback is..view needs to be get refreshed for retrieving updated data.
Difference between Store Procedure and Trigger?
What is the advantage to use trigger in your PL?
Triggers are fired implicitly on the tables/views on which they are created. There are various advantages of using a trigger. Some of them are:
What the difference between UNION and UNIONALL?
Union will remove the duplicate rows from the result set while Unionall does'nt.
What is the difference between TRUNCATE and DELETE commands?
Both will result in deleting all the rows in the table .TRUNCATE call cannot be rolled back as it is a DDL command and all memory space for that table is released back to the server. TRUNCATE is much faster.Whereas DELETE call is an DML command and can be rolled back.
Which system table contains information on constraints on all the tables created ?
system table contains information on constraints on all the tables created
Explain normalization ?
Normalisation means refining the redundancy and maintain stablisation. there are four types of normalisation :
first normal forms, second normal forms, third normal forms and fourth Normal forms.
How to find out the database name from SQL*PLUS command prompt?
Select * from global_name;
This will give the datbase name which u r currently connected to.....
What is the difference between SQL and SQL Server ?
SQLServer is an RDBMS just like oracle,DB2 from Microsoft
Structured Query Language (SQL), pronounced "sequel", is a language that provides an interface to relational database systems. It was developed by IBM in the 1970s for use in System R. SQL is a de facto standard, as well as an ISO and ANSI standard. SQL is used to perform various operations on RDBMS.
What is diffrence between Co-related sub query and nested sub query?
Correlated subquery runs once for each row selected by the outer query. It contains a reference to a value from the row selected by the outer query.
Nested subquery runs only once for the entire nesting (outer) query. It does not contain any reference to the outer query row.
select e1.empname, e1.basicsal, e1.deptno from emp e1 where e1.basicsal = (select max(basicsal) from emp e2 where e2.deptno = e1.deptno)
select empname, basicsal, deptno from emp where (deptno, basicsal) in (select deptno, max(basicsal) from emp group by deptno)
WHAT OPERATOR PERFORMS PATTERN MATCHING?
Pattern matching operator is LIKE and it has to used with two attributes
1. % and
2. _ ( underscore )
% means matches zero or more characters and under score means mathing exactly one character
1)What is difference between Oracle and MS Access?
2) What are disadvantages in Oracle and MS Access?
3) What are feratures&advantages in Oracle and MS Access?
Oracle's features for distributed transactions, materialized views and replication are not available with MS Access. These features enable Oracle to efficiently store data for multinational companies across the globe. Also these features increase scalability of applications based on Oracle.
What is database?
A database is a collection of data that is organized so that itscontents can easily be accessed, managed and updated. open this url : http://www.webopedia.com/TERM/d/database.html
What is cluster.cluster index and non cluster index ?
Clustered Index:- A Clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table may have only one clustered index.Non-Clustered Index:- A Non-Clustered 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 in the disk. The leaf nodes of a non-clustered index does not consists of the data pages. instead the leaf node contains index rows.
How can i hide a particular table name of our schema?
you can hide the table name by creating synonyms.
e.g) you can create a synonym y for table x
create synonym y for x;
What is difference between DBMS and RDBMS?
The main difference of DBMS & RDBMS is
RDBMS have Normalization. Normalization means to refining the redundant and maintain the stablization.
the DBMS hasn't normalization concept.
What are the advantages and disadvantages of primary key and foreign key in SQL?
1) It is a unique key on which all the other candidate keys are functionally dependent
1) There can be more than one keys on which all the other attributes are dependent on.
1)It allows refrencing another table using the primary key for the other table
Which date function is used to find the difference between two dates?
for Eg: select datediff (dd,'2-06-2007','7-06-2007')
output is 5
For Further Reading,