|
|
| Re: Some SQL Questions [message #405813 is a reply to message #405810] |
Fri, 29 May 2009 11:55  |
 |
Michel Cadot
Messages: 68718
Registered: March 2007
Location: Saint-Maur, France, https...
|
Senior Member
Account Moderator |
|
|
Q) When will say your database in normalized form?
Normalization
Q) Select * from emp where rownum=2.
ROWNUM
Q) In where clause NVL and Decode are valid?
Yes
Q) Without select statement we can use DECODE AND CASE?
Yes
Q) when do you ambiguous replace error?
What does that mean?
Q) using NULL can you create foreign key relation?
Yes
Q) How will you change the CLOB data type to NCLOB datatype?
DBMS_REDEFINITION
Q) What is the difference between subquery and joins, which will execute faster?
Joins Subqueries
Q) What is forward rollback?
rolling forward, if this is what you mean as forward rollback is meaningless.
Q) How will be maintaining one to one, one to many and many to many relations?
Foreign keys, child tables
All is in the documentation. I recommend you to read:
Database Concepts
SQL Reference
Regards
Michel
|
|
|
|
] 
Blog
Search
Help
Members
Register
Login
Home
