--创建学生信息表,约束放在所有列定义之后 CREATE TABLE stu_info( stu_id INTEGER, stu_name NVARCHAR2() NOT NULL, stu_sex ) NOT NULL, stu_age INTEGER NOT NULL, stu_address NVARCHAR2() NOT NULL, stu_email NVARCHAR2(), stu_tele INTEGER NOT NULL, tch_id INTEGER, CONSTRAINT s…