efficient searching in database - oracle

Question

I have a database containing user details. I don't have separate columns for 'firstname' and 'lastname'. I have used only a single column: 'name'. My query is like this:
ps_details=con.prepareStatement("select * from student_details where name=?");
ps_details.setString(1,name);
The problem is:
In db the name is stored in UPPERCASE. So when the user types his/her name in lowercase or mixed-case, the search is unsuccessful. What is the efficient solution for this problem?
Further, what if 'name' are stored in db in lower-case, mixed-case as well as uppercase, i.e., if the case is not known before hand. I also want to use like clause
I am using Oracle 11g Express Editon.

Answer 1

If you really intend to do an exact match (i.e. the user needs to enter their entire name in order to do the search rather than just entering a portion of their name), you can wrap both sides of the expression in either the UPPER or the LOWER function.
SELECT *
FROM student_details
WHERE upper(name) = upper(?)
If you do that, however, Oracle won't be able to use an index on name so it will have to scan the entire table. That's not particularly efficient. You can address that issue by creating a function based index on upper(name)
CREATE INDEX idx_upper_name
ON student_details( upper(name) );
In reality, though, I suspect that you don't want to do a wild-card based match. You almost certainly want to allow the user to enter some part of the name and to return the results that contain that string. So if I were a student, you probably want to allow the user to search for either 'Justin' or 'Cave' or 'Justin Cave' or 'Just' and have all those searches return my row (along with whatever other rows match, of course). If you want to do that, the simplest approach would be to use the LIKE function along with the % wildcard
SELECT *
FROM student_details
WHERE upper(name) like '%' || upper(?) || '%'
will return all the rows where the input string is found anywhere in the text you're searching. But that realistically takes us back to nearly square one with respect to performance-- having the leading wildcard is going to make it very difficult for Oracle to benefit from using the index we defined on UPPER(name). This is why most people would store first and last name separately. That allows them to do something like
SELECT *
FROM student_details
WHERE upper(first_name) like upper(?) || '%'
OR upper(last_name) like upper(?) || '%'
This allows them to return my row whether the user searches for 'Justin' or 'Cave' or 'Just' and regardless of the casing of the data in the database or the data that is entered in the search. And it is able to use appropriate function-based indexes on the data.

Answer 2

UPPER - the upper function converts all letters in the specified string to uppercase. Use it on both the variable (user input) and table column values, convert them both to the same case for comparison to handle both problems. (You could also use lower - the idea is to convert both to the same case for comparison). *EDITED FOR LIKE with only the postceding wildcard *
select * from student_details where UPPER(name) like UPPER(?) || '%'
This you have to play with, but I think you can also do the following with the wildcard.
ps_details=con.prepareStatement("select * from student_details where UPPER(name) like UPPER(?)");
ps_details.setString(1,name%);

Answer 3

Try using UPPER() on your input.