I am using Oracle Express 10g and I\'m enter the following text to create 2 tables in the sql command line, but it is not working.
CREATE TABLE student (
mat
By "command line" you probably mean the web application that comes with Oracle Express 10g. This application has several browser incompatibilities and is basically unable to execute several statements at once (also see Oracle 10g - invalid character on DB importing).
Either put your statements in a text file and upload them as a SQL script. Or switch to a better tool such as SQL Developer (downloadble from Oracle web site).