'Red boat' diaporamas de présentation

SQL: Structured Query Language

SQL: Structured Query Language. Chapter 5. R1. Example Instances. We will use these instances of the Sailors and Reserves relations in our examples. S1. If the key for the Reserves relation contained only the attributes sid and bid , how would the semantics differ?. S2.

1.15k views • 98 slides

SQL Examples

Edited by John Shieh. SQL Examples. SELECT [DISTINCT] target-list FROM relation-list WHERE qualification. qualification Comparisons ( Attr op const or Attr1 op Attr2 , where op is one of ) combined using AND , OR and NOT . DISTINCT

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Relational Algebra

p. Relational Algebra. R & G, Chapter 4. By relieving the brain of all unnecessary work, a good notation sets it free to concentrate on more advanced problems, and, in effect, increases the mental power of the race . -- Alfred North Whitehead (1861 - 1947). Administrivia.

500 views • 36 slides

SQL: Structured Query Language

SQL: Structured Query Language. Chapter 5. R1. Example Instances. We will use these instances of the Sailors and Reserves relations in our examples. If the key for the Reserves relation contained only the attributes sid and bid , how would the semantics differ?. S1. S2.

302 views • 30 slides

ICS 321 Fall 2011 The Relational Model of Data ( i )

ICS 321 Fall 2011 The Relational Model of Data ( i ). Asst. Prof. Lipyeow Lim Information & Computer Science Department University of Hawaii at Manoa. Data Models. A data model is a collection of concepts for describing data Structure of the data.

338 views • 27 slides

Math in SQL

Math in SQL. Aggregation Operators. Operators on sets of tuples. Significant extension of relational algebra. SUM ( [DISTINCT] A) : the sum of all (unique) values in attribute A. AVG ( [DISTINCT] A): the average of all (unique) values in attribute A . SELECT AVG ( S.age )

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DB Review Session

DB Review Session. salary. ER Diagrams 1. title. birthday. id. Movie. Actor. year. Acted In. name. type. address. Where does the salary attribute belong?. role. ER Diagrams 2. The entities in a relationship set identify the relationship. id. Actor. Movie. Acted In. title.

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Database Systems I Admin Stuff

Database Systems I Admin Stuff. Mid-term exam Tuesday, Oct 19 @ 2:30pm Room 3005 (usual room) Closed book No cheating, blah blah No class on Oct 21 The amount of time we spent on each topic in class is a good indication of importance & likelihood of exam question.

399 views • 24 slides

Relational Calculus

?. Relational Calculus. ?. Logic, like whiskey, loses its beneficial effect when taken in too large quantities. --Lord Dunsany. Relational Calculus. Query has the form: { T | p ( T )} p(T) is a formula containing T Answer = tuples T for which p ( T ) = true . Formulae.

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Relational Calculus

?. Relational Calculus. ?. CS 186, Spring 2006, Lecture 9 R&G, Chapter 4. We will occasionally use this arrow notation unless there is danger of no confusion. Ronald Graham Elements of Ramsey Theory. Relational Calculus.

518 views • 18 slides

Relational Calculus

Relational Calculus. R&G, Chapter 4. Relational Calculus. Comes in two flavors: Tuple relational calculus (TRC) and Domain relational calculus (DRC) . Calculus has variables, constants, comparison ops , logical connectives and quantifiers .

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Exercises

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