1)how to create multiple tables using single command?
2)what is boys codds normal form?
3) What is null? which option is correct?
f. None of the above
4)in which normal form functional dependendencies
5)what is fourth normal form ?
6)what type of relationship(parent/child) exists
in hierarchial model ?
7)what is returned for %isopen in implicit cursor?
8)which one doesnot consider null?
1) Can't. You can run a script that has multiple create table statements in it, but there is not a command that says "create the following tables..."
2) Boyce-Codd normal form is how relational databases are structured with respect to how tables are designed. You can look this up on the Internet, look in any database design book, etc. The goal for most designs is third normal form (3NF). Google returned (only) 3,460 hits in .12 seconds, so I am sure that with a little effort, you can find a link that will help you.
3) Nulls are nulls, they are not equal to anything, nor are they equal to each other (a null value does not equal another null value). The concept of a null is understandable, the value of a null is not zero, and an attribute can be assigned a null value.
4-6) When you read up on BCNF, you'll be able to answer these questions.