Order now
     

EXPLAIN shows information about the database: the number of tables; how tables are joined; how data is looked up (full table scan, full index scan or partial index scan); the presence of subqueries, sorts, and unions; DISTINCT and WHERE clauses are used; indexes used and their length (longer index – longer search); number of records examined

iLAB OVERVIEW

Scenario and Summary

EXPLAIN shows information about the database: the number of tables; how tables are joined; how data is looked up (full table scan, full index scan or partial index scan); the presence of subqueries, sorts, and unions; DISTINCT and WHERE clauses are used; indexes used and their length (longer index – longer search); number of records examined

Deliverables

Grading of the lab assignment will be based on the following.

Assignment Step Description Points
Step 1 EXPLAIN #1 – describe Output of EXPLAIN 6
Step 2 EXPLAIN #2  to have type as partial index scan 6
Step 3 EXPLAIN #3 to have type as index_merge 6
Step 4 EXPLAIN #4 to have type = fulltext 6
Step 5 EXPLAIN #5  to have type as const 6
Step 6 EXPLAIN #6 Sample subquery example 6
Step 7 EXPLAIN #7 – describe Output of EXPLAIN with join 6
Step 8 EXPLAIN #8 – EXPLAIN EXTENDED 6
Step 9 Explain warnings using SHOW WARNINGS 6
Step 10 Explain UPDATE statement 6
Total iLab Points 60 Points

Submit your lab session–showing any queries, and other SQL code, and the resulting return from the database–to the Dropbox for the Week 5 iLab.

 

iLAB STEPS

1)      STEP 1: EXPLAIN Output – test EXPLAIN #1

Mysql> EXPLAIN select column from database.tablename where column = value\G

\G – capital letter G  places the result set vertically

Explain the meaning and values of result columns (id, table, type, possible_keys, key, key_len, ref, rows, Extra)

Save the screenshot.

2)      STEP 2: Modify EXPLAIN in step #1  – test EXPLAIN #2  to have type as partial index scan by including one of the following:

<, <=, >, >=, IS NULL, BETWEEN, IN

Explain output of EXPLAIN. Save the screenshot.

3)      STEP 3: Modify EXPLAIN in step #1 – test EXPLAIN #3 to have type as index_merge by including LIKE statement

Explain output of EXPLAIN. Save the screenshot.

4)      STEP 4: Modify EXPLAIN #1  – test  EXPLAIN #4 to have type = fulltext data access

To write SELECT which causes fulltext data access –select job_category and job_title of the job with  title or description which include the word ‘programmer’.

Example:

EXPLAIN select job_category, job_title from bonus where MATCH (job_title, job_description) AGAINST (‘programmer’)\G

Explain output of EXPLAIN. Save the screenshot.

5)      STEP 5:  Modify EXPLAIN #1 – test EXPLAIN #5  to have type as const by joining/looking up unique index values (index fields compared with =)

Example:

EXPLAIN select hire_date from employee where employee_id = 1234;

Explain output of EXPLAIN. Save the screenshot.

6)      STEP 6: Sample subquery example – test EXPLAIN #6

Write EXPLAIN select statement using subquery.

Example:

EXPLAIN select employee_id, employee_name IN (select job_category from bonus AS bonus_subquery where bon_comm IS NULL) from employee AS outer\G

Explain output of EXPLAIN. Save the screenshot.

7)      STEP 7: Turn subquery in #6 to join – test EXPLAIN #7.

Explain output of EXPLAIN. Save the screenshot.

8)      STEP 8: To know the approximate number of examined rows to be returned,  modify EXPLAIN #1 to EXPLAIN EXTENDED – test EXPLAIN #8

Mysql> EXPLAIN  EXTENDED select column from database.tablename where column = value\G

Explain output of EXPLAIN EXTENDED (values of rows and filtered columns)

9)      STEP  9: Explain warnings received in step #8 by using command:

Mysql>SHOW WARNINGS\G

10)  STEP 10: Explain UPDATE statement – test EXPLAIN #9

Example:

Explain update table_name set column_name = value\G

Explain update mis561.employee set table1col = ‘val’\G

 

Explain output of EXPLAIN. Save the screenshot.

Attachments:

Place a similar order with us or any form of academic custom essays related subject and it will be delivered within its deadline. All assignments are written from scratch based on the instructions which you will provide to ensure it is original and not plagiarized. Kindly use the calculator below to get your order cost; Do not hesitate to contact our support staff if you need any clarifications.

Type of paper Academic level Subject area
Number of pages Paper urgency Cost per page:
 Total:

Whatever level of paper you need – college, university, research paper, term paper or just a high school paper, you can safely place an order.