# SQL3 questions.pdf - Databases - Relational Algebra and SQL...

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Databases - Relational Algebra and SQL 3Jianxin LiSchool of Computer Science & Software EngineeringUniversity of Western AustraliaJianxin Li (UWA)Lab 41 / 6
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Chapter 13 / Exercise 7
Database Systems: Design, Implementation, & Management
Coronel/Morris
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Relational AlgebraSome of the answers will require you to type relational algebra expressionssuch asπid(σ(a>10)((R./S)×T))(1)To write these in text, do the followingUse the words rho, pi and sigma forρ,πandσUse an underscore for subscriptsUse the word bowtie for./and the letter x for×So you will type: pi_id(sigma_(a>10) ((R bowtie S) x T))Jianxin Li (UWA)Lab 42 / 6
Relational AlgebraThe first few questions will use a student, unit, grade database similar to theone from lectures, but where the tables are called S (for student), U (for unit)and G (for grade) and have the following schema:S(sid, name, gender)U(uid, name)G(sid, uid, grade)Students have a unique id, a name and a gender (either M or F) , Units have anunique id (like CITS1402) and a name (like Databases), while Grades indicatewhat grade the student with id sid achieved when they took the unit with iduid.

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##### We have textbook solutions for you!
The document you are viewing contains questions related to this textbook.
The document you are viewing contains questions related to this textbook.
Chapter 13 / Exercise 7
Database Systems: Design, Implementation, & Management
Coronel/Morris
Expert Verified