i am developing a site for library in php and oracle.somebody told me to use MySql.i want to ask can database make difference?
The type of database you use will make a difference if the site is medium - large. Otherwise, you probably won't notice it that much. Also, Oracle can get quite expensive and is much harder to learn than MySQL (which is open source). So if you wanted to try something other than MySQL you could try PostgreSQL which is pretty popular.