SQLs counterpart of the key words:
The text from the opening parenthesis to the end of the fourth line specifies the declared type of the table, meaning that every table ever assigned to ENROLMENT must be a table of that type.The declared type of ENROLMENT is a table type, indicated by the key word TABLE and a comma-separated list (commalist, for short) of column definitions. A column definition consists of a column name followed by a type specification. Thus, each column of the table also has a declared type. Two or more columns can have the same type but not the same name. The type names SID and CID (for student ids and course ids) refer either to user-defined types or to user-defined domains. User-defined types and domains have to be defined by some user of the DBMS before they can be referred to. The type name VARCHAR(30) (character strings of length 30 or less), by contrast, is a predefined type: it is provided by the DBMS itself, is available to all users, and cannot be destroyed.