You need to design a student registration database that contains several tables storing academic information. The STUDENTS table stores information about a student. The STUDENT_GRADES table stores information about the student's grades. Both of the tables have a column named STUDENT_ID. The STUDENT_ID column in the STUDENTS table is a primary key. You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table that points to the STUDENT_ID column of the STUDENTS table. Which statement creates the foreign key?（） CREATE TABLE student_grades (student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk REFERENCES (student_id) FOREIGN KEY student (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT FOREIGN KEY (student_id) REFERENCES student (student_id));。 CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id))。
The ‘lsvg -o’ command is run with an output of only rootvg， but the server has another volume group named datavg， which is not displayed. What is the likely cause？（） datavg is in an offline state.。 ‘lsvg -o’ only displays the root volume group.。 ‘lsvg -o’ only displays the fist volume group.。 datavg has no filesystems and therefore， is inactive.。
我国小学阶段，德育内容主要体现在（）中 班级教育活动。 思想品德课。 全校性思想政治教育活动。 班会和校会。
大肠杆菌属于（） 专性好氧菌。 兼性厌氧菌。 耐氧菌。 厌氧菌。
Your database is open and users are connected using the LISTENER listener. The new DBA of the system stops the listener by using the following command： LSNRCTL> STOP What would happen to the sessions that are presently connected to the database instance？（） The sessions are able to perform only queries.。 The sessions are not affected and continue to function normally.。 The active transactions are rolled back and the sessions get terminated.。 The sessions are not allowed to perform any operations till the listener is started.。
某人在一段时间里常常感到情绪低落，兴趣减退，对前途悲观失望，总是提不起精神来。根据这些表现可判断该人的情绪是（）
