1. PART Evaluation and optimization: A schema of the ski shop information system is given: Customer (cid, name, surname, address, telephone); Employee (eid, name, surname, address, telephone); Purchase (pid, sid, cid, eid, date); Skiis (sid, brand, model, length, hardness) Additional information is given: | Customer] =150 pages, 40 records/page | Employee | = 2 pages, 40 records/page | Purchase | = 2000 pages, 100 records/page | Skiis | = 250 pages, 30 records/page Buffer can store up to 2500 pages. Let's assume that the following indices are now set on the schema from the previous task: Level 2 B+ index on the attribute Purchase.date Hash index on the attribute Skiis.sid - Our DBMS has the following algorithms to perform the join: - Hash join - Index nested loops join - Sort-merge join Translate the following SQL query into relational algebra and find the plan that reads the fewest pages or blocks: SELECT Skiis.model, Skiis.length FROM Skiis JOIN Purchase ON (Skiis.sid = Purchase.sid) WHERE Skiis.brand = 'Elan' AND Purchase.date > '31.12.2023'
1. PART Evaluation and optimization: A schema of the ski shop information system is given: Customer (cid, name, surname, address, telephone); Employee (eid, name, surname, address, telephone); Purchase (pid, sid, cid, eid, date); Skiis (sid, brand, model, length, hardness) Additional information is given: | Customer] =150 pages, 40 records/page | Employee | = 2 pages, 40 records/page | Purchase | = 2000 pages, 100 records/page | Skiis | = 250 pages, 30 records/page Buffer can store up to 2500 pages. Let's assume that the following indices are now set on the schema from the previous task: Level 2 B+ index on the attribute Purchase.date Hash index on the attribute Skiis.sid - Our DBMS has the following algorithms to perform the join: - Hash join - Index nested loops join - Sort-merge join Translate the following SQL query into relational algebra and find the plan that reads the fewest pages or blocks: SELECT Skiis.model, Skiis.length FROM Skiis JOIN Purchase ON (Skiis.sid = Purchase.sid) WHERE Skiis.brand = 'Elan' AND Purchase.date > '31.12.2023'
Chapter2: Database Design Fundamentals
Section: Chapter Questions
Problem 11RQ
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Please translate the following SQL query into relational algebra and find the plan that reads the fewest pages or blocks:
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