<alter class statement>
| <alter trigger statement>
| <alter serial statement>
ALTER [ <class type> ] <class name> <alter clause>
ADD <alter add> [ INHERIT <resolution comma list> ]
| DROP <alter drop> [ INHERIT <resolution comma list> ]
| CHANGE <alter change>
| RENAME <alter rename> [ INHERIT <resolution comma list> ]
CLASS ATTRIBUTE <attribute definition comma list>
| [ ATTRIBUTE | COLUMN ] <class constraint or attribute definition comma list>
| SUPERCLASS <class name comma list>
| QUERY <query statement>
[ ATTRIBUTE | COLUMN ] <attribute name comma list>
| CONSTRAINT <constraint name>
| SUPERCLASS <class name comma list>
<attribute default comma list>
| QUERY [ <unsigned integer literal> ] <query statement>
[ CLASS ] <attribute name> DEFAULT <value specification>
[ ATTRIBUTE | COLUMN ] [ CLASS ] <attribute name> AS <attribute name>
ALTER TRIGGER <trigger name> <trigger status or priority>
STATUS { ACTIVE | INACTIVE }
| PRIORITY <trigger key>
ALTER SERIAL <serial name> [ INCREMENT BY <integer literal> ] [ START WITH <integer literal> ]
[ MINVALUE <integer literal> | NOMINVALUE]
[ MAXVALUE <integer literal> | MAXVALUE] [ CYCLE | NOCYCLE ]
ALTER CLASS procedings ADD SUPERCLASS reports
INHERIT editor OF reports;
ALTER CLASS employee ADD ATTRIBUTE
name string,
age integer DEFAULT 20;
ALTER CLASS employee DROP name, age;
ALTER CLASS employee CHANGE age DEFAULT 30;
ALTER CLASS employee DROP CONSTRAINT unique_age;