What are the challenges associated with "diamond dependency" problems?

Develop a logical data model based on the following requirements:• Refinement of the conceptual model - including a refined Enhanced Entity-Relationship (EER) diagram.• Derivation of relations from the refined conceptual model.• Validation of logical model using normalization to BCNF.• Validation of logical model against corresponding user transactions.• Definition of integrity constraints including:- Primary key constraints.- Referential Integrity (foreign key) constraints.- Entity integrity (NULL and default value) constraints.- Alternate key constraints.- General constraints if any.   Entities Airplane Model Technician Expertise Traffic Controller Medical Examination Union Test Testing Event Relationships Airplane is of Model (1:M) Technician has Expertise in Model (M:M) Traffic Controller undergoes Medical Examination (1:1) Employee belongs to Union (1:1) Airplane is Tested using Test (M:M) Testing Event records Airplane, Technician, and Test (M:M:M) Attributes Airplane…

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…