Question

Query Tree: Algebra symbol pi .......> EMP_ID, E_ID,CUSTOMER_ID,C_ID, CITY, FNAME EMP_ID=E_ID sigma(parser) EMP_ID='12469' Entities Employee sigma Customer_ID=C_ID City_ID='Jeddah' Customer Order Here sigma is for parsing value $\sigma$, keep the entity values Employee, Customer, Order values denotes as $\infty$, attributes as $\pi$ ->o is for intersecting or joining the table.

          Query Tree:
Algebra symbol pi
.......> EMP_ID, E_ID,CUSTOMER_ID,C_ID, CITY, FNAME
EMP_ID=E_ID
sigma(parser) EMP_ID='12469'
Entities Employee
sigma
Customer_ID=C_ID
City_ID='Jeddah'
Customer
Order
Here sigma is for parsing value $\sigma$, keep the entity values Employee, Customer, Order values
denotes as $\infty$, attributes as $\pi$
->o is for intersecting or joining the table.

Query Tree:
Algebra symbol pi
.......> EMPID, EID,CUSTOMERID,CID, CITY, FNAME
EMPID=EID
sigma(parser) EMPID='12469'
Entities Employee
sigma
CustomerID=CID
CityID='Jeddah'
Customer
Order
Here sigma is for parsing value σ, keep the entity values Employee, Customer, Order values
denotes as ∞, attributes as π
->o is for intersecting or joining the table.

Added by Valerie O.

Computer Science and Information Technology

Trishna Knowledge Systems 2018 Edition

Instant Answer

Solved by Expert Aarya B

06/26/2023

Step 1

City='Jeddah'" down to the Customer table. Query Tree after applying the rule: Query Tree: Algebra symbol π > EMP_ID, E_ID, CUSTOMER_ID, C_ID, CITY, FNAME EMP_ID = E_ID CUSTOMER_ID = C_ID σ (parser) EMP_ID = '12469' σ (parser) CITY = 'Jeddah' Entities: Employee, Show more…

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Thanks for your feedback!

Optimize the following SQL Query by using Query Tree and Heuristic Rules: SELECT C.Fname, E.Fname FROM Employee AS E, Customer AS C, Order AS O WHERE E.EMP_ID=O.E_ID AND C.City='Jeddah' AND C.Customer_ID=O.C_ID AND E.EMP_ID='12943' You should show the Initial Query Tree and add a screenshot of the Query Tree after applying each rule. This is the query tree: Query Tree: Algebra symbol π > EMP_ID, E_ID, CUSTOMER_ID, C_ID, CITY, FNAME EMP_ID = E_ID CUSTOMER_ID = C_ID σ (parser) EMP_ID = '12469' σ CITY = 'Jeddah' Entities: Employee, Customer, Order Here, σ is for parsing value o, keeping the entity values Employee, Customer, Order values denoted as oo, and attributes as TT. -> o is for intersecting or joining the table.