单项选择题 How many expansion frames can be attached to an IBM TS3500 model L23 or L53 base frame? （）

单项选择题 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？（）

单项选择题 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 students 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?（）