Introduction to Database Systems Queries in SQL The select ...

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On the supplier and parts DB: Exercise Supplier(sid, sname, address) Part(pid, pname, colour) Catalog(sid, pid, cost) 1. Suppliers that supply only red parts 2. Suppliers that supply all red parts 87 Nested Queries: Visibility persons having at least one child. select * from person where exists (select * from fatherChild where father = name) or exists (select * from motherChild where mother = name) The attribute name refers to the table person in the outer from clause. 88
More on Visibility Note: This query is incorrect: select * from employee where dept in (select name from department D1 where name = 'Production') or dept in (select name from department D2 where D2.city = D1.city) employee name lastName dept department name address city 89 Visibility: Variables in Internal Blocks Name and income of the fathers of persons who earn more than 20k, showing also the income of the child. select distinct f.name, f.income, c.income from person f, fatherChild, person c where f.name = fc.father and fc.child = c.name and c.income > 20 In this case, the “intuitive” nested query is incorrect: select name, income, c.income from person where name in (select father from fatherChild where child in (select name from person c where c.income > 20)) 90
Page 1 and 2: Introduction to Database Systems Qu
Page 3 and 4: Naming Conventions • To avoid amb
Page 5 and 6: Usage of “as” in select Stateme
Page 7 and 8: select with Asterisk Given a relati
Page 9 and 10: Handling of Null Values Employees w
Page 11 and 12: SQL and Relational Algebra Given th
Page 13 and 14: MotherChild mother child Lisa Mary
Page 15 and 16: Exercise 4: Solution “Father and
Page 17 and 18: Explicit Join For every person, ret
Page 19 and 20: A Further Extension: Natural Join (
Page 21 and 22: Ordering the Result: order by selec
Page 23 and 24: Results of count: Example FatherChi
Page 25 and 26: Aggregate Operators and the Target
Page 27 and 28: Exercise 7: group by “For each gr
Page 29 and 30: Conditions on Groups It is also pos
Page 31 and 32: Union, Intersection, and Difference
Page 33 and 34: Positional Notation (cntd) Renaming
Page 35 and 36: Single Block Queries: Exercises (cn
Page 37 and 38: Nested Queries: Example Name and in
Page 39 and 40: Nested Queries: Example with all
Page 41 and 42: Nested Queries and Negation All the
Page 43: Exercise 9: Solution with not exist
Page 47 and 48: Exercise 10: Solution “Name and a
Page 49 and 50: Exercise 11 Can one express set dif
Page 51 and 52: Exercise 12: Solution “The person
Page 53 and 54: Solution with Views create view age
Page 55 and 56: Generic Integrity Constraints: chec
Page 57 and 58: Characteristics of Privileges A pri
Page 59 and 60: Example Transaction in SQL begin tr
Page 61 and 62: Transactions • A transaction is a
Page 63 and 64: Transactions are … Durable • Af
Page 65 and 66: Integrity Checking and Transactions
Page 67 and 68: Concurrency Control • There are t
Page 69 and 70: Isolation Levels Prevent Violations
Page 71 and 72: Transactions (Example ctd) Lubber a

Introduction to Database Systems Queries in SQL The select ...

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