composite index vs normal index I need to index some  tables and for that i found that there are different kinds of indexing.  I am kind of clueless on their proper place of usage.
Should i create index on all the fields that want to retrieve quickly or Should i create composite index on couple of fields?
Is it OK to create composite indexes along with the normal indexes? suppose i have 3 fields :

FirstName 
LastName 
State


Can i individually index each field and then have different composit indexes on these fields as well?
For example by writing :

Create index indx_name on tblTest(FirstName);
Create index indx_lastname on tblTest(Last name); 
Create index indx_state on tblTest(state);
create index indx_cmp_fls on tblTest(FirstName,LastName,state); 
create index indx_cmp_lfs on tblTest(LastName,FirstName,state);
create index indx_cmp_sfl on tblTest(state,FirstName,LastName);
create index indx_cmp_slf on tblTest(state,LastName,FirstName);


Is it OK?
Is it suggested? if not what is the best way ? 
Is it also OK to have index on all fields ?
Your question amounts to, "How do I use indexes?" You should read some Oracle documentation to get up to speed on how to use indexes and how to determine what columns to index. Oracle has an entire library of free online books and documentation for their products. A few good links to start:


The chapter on Indexes and Index-organized Tables from Oracle Database Concepts (the entire book is definitely worth reading)
The Oracle Database Performance Tuning Guide on Choosing Columns and Expressions to Index
Using Indexes in Database Applications from the 
Oracle Database Advanced Application Developer's Guide