Question

I have a program which i should ensure that a URL exist or not, if exists in the database, i should select the ID if not i should insert it to the database.

I have a question, Is GetHashCode is a good approach to save the hash code in the database and just compare the hash codes? Can I be sure there is no exception which 2 or more URLs has equal hash codes and if not Is it different which .NET Framework is installed?

Thanks

Answer 1

1. Don’t use the out of the box GetHashCode(), it is week and might change in the next version.
2. Use your own hash function using SHA1/SHA2.
   • Don’t use MD4/MD5 because they are broken.
3. You need to deal with escaping, I.E. ‘A B’== ‘A%20B’
4. You also need to consider what to-do with case sensitivity.