Although a user directory is treated as a file, it is flagged to indicate to the file manager that this file is really a subdirectory whose records are filenames that point to files.
ASDF JKL; are the home row keys.
Answer:
An online company wants to conduct real-time sentiment analysis about its products from its social media channels using SQL. The solution which has lowest cost and operational burden is as follow:
B. Configure the input stream using Amazon Kinesis Data Streams. Use Amazon Kinesis Data Analytics to write SQL queries against the stream.
Explanation:
- The option A is not correct as this solution doesn't have lowest cost and operational burden as set up a streaming data ingestion application on Amazon EC2 and connect it to a Hadoop cluster for data processing will have more cost and operational burden.
- The lowest cost and operational burden solution is that we configure input stream using Amazon Kinesis Data Streams. We can use Amazon Kinesis Data Analytics to write SQL queries against the stream.
- The option c and d are also more pricey in terms of cost and operational burden as compared to Amazon Kinesis Data stream and analytics.
For the view of Exercise 4.18, explain why the database system would not allow a tuple to be inserted into the database through this view.
For reference
For the database of Figure 4.12, write a query to find the ID of each employee with no manager. Note that an employee may simply have no manager listed or may have a null manager. Write your query using an outer join and then write it again using no outer join at all.
OUTER JOIN
select e.ID from employee e left outer join manages m on e.ID = m.ID
where m.manager_id is null;
NO OUTER
select e.ID from employee e where e.ID not in (select m.ID from manages m) or e.ID in (select m.ID from manages m where m.manager_id is null);
Answer:
876100
019343
Explanation:
10s complement of a decimal number is obtained by the following process:
- Obtain 9s complement ( Subtract each digit by 9)
- Add 1 to the result
1) 123900
9s complement => (9-1)(9-2)(9-3)(9-9)(9-0)(9-0)
= 876099
Adding 1 , 10s complement of 123900 = 876100
2) 980657
9s complement = (9-9)(9-8)(9-0)(9-6)(9-5)(9-7)
= 019342
Adding 1 , 10s complement of 980657 = 019343
