Aerospace Information
1. Write the wordcount pseudocode of the classic Spark algorithm (both java, scala and python) (5 points)
1. Database part (10 points in total)
1. Set the structure of the student table and the course table as (student number, name) and (student number, course number, grades). If you want to find out "names of students with scores greater than 90 points". The corresponding SOL sentence is (). (2 minutes)
A, SELECT name FROM student table WHERE student table. Student number one course table. Student number AND course table. Score>90
B, SELECT name FROM course table WHERE student table. Student ID = course table. Student ID AND course table. Grade> 90
C.SELECT name FROM student table, course table WHERE student table. Student ID=course table. Student ID OR course table. Score>90
D. SELECT name FROM student table, course table WHERE student table. Student ID=course table. Student ID AND course table. Score>90
2. When performing a database query, if there is a lot of data to be queried, the following method is to improve the query efficiency () (4 points)
A Use connection pool to increase database execution threads
B Use PreparedStatement repeatedly. Reduce the number of queries
C Increase the database buffer to improve database I/O performance
D index
3. Here are the names of students whose courses are greater than 80: Student table stulent score long grade (4 points)
2. Short answer questions (40 points)
(1) Existing set A (collective learning section is Jxfp _id, gf_ nsr_ key, je, se), B (collection fields are jxfp_id, gf_nsr_key, wpmc). The associated field of the two sets is jxfp_id, please calculate set C ( CAB) (5 points)
(2) Please complete the following method, the purpose of this method is to calculate the result in a recursive way (5 points)
public static double recursive（int i）{
}
(3) Briefly describe the main functional nodes of HDFS and their functions (0 points)
(4) Explain the factory model (5 points)
(5) Briefly describe the three main function nodes of the MapReduce framework and their functions? (10 points)