🗊Презентация Relational Algebra

Категория: Образование
Нажмите для полного просмотра!
Relational Algebra, слайд №1Relational Algebra, слайд №2Relational Algebra, слайд №3Relational Algebra, слайд №4Relational Algebra, слайд №5Relational Algebra, слайд №6Relational Algebra, слайд №7Relational Algebra, слайд №8Relational Algebra, слайд №9Relational Algebra, слайд №10Relational Algebra, слайд №11Relational Algebra, слайд №12Relational Algebra, слайд №13Relational Algebra, слайд №14Relational Algebra, слайд №15Relational Algebra, слайд №16Relational Algebra, слайд №17Relational Algebra, слайд №18Relational Algebra, слайд №19Relational Algebra, слайд №20Relational Algebra, слайд №21Relational Algebra, слайд №22Relational Algebra, слайд №23Relational Algebra, слайд №24Relational Algebra, слайд №25Relational Algebra, слайд №26Relational Algebra, слайд №27Relational Algebra, слайд №28Relational Algebra, слайд №29Relational Algebra, слайд №30Relational Algebra, слайд №31Relational Algebra, слайд №32Relational Algebra, слайд №33Relational Algebra, слайд №34Relational Algebra, слайд №35Relational Algebra, слайд №36Relational Algebra, слайд №37
Скачать
Вы можете ознакомиться и скачать презентацию на тему Relational Algebra. Доклад-сообщение содержит 37 слайдов. Презентации для любого класса можно скачать бесплатно. Если материал и наш сайт презентаций Mypresentation Вам понравились – поделитесь им с друзьями с помощью социальных кнопок и добавьте в закладки в своем браузере.

Слайды и текст этой презентации

Слайд 1


Lecture 6. Relational algebra National Aviation University Computer Science Faculty Department of Software Engineering
Описание слайда:
Lecture 6. Relational algebra National Aviation University Computer Science Faculty Department of Software Engineering

Слайд 2


CONTENTS Query languages in DB Properties of binary operations Relational algebra operations Examples Equivalent transformation and optimization of relational algebra expressions
Описание слайда:
CONTENTS Query languages in DB Properties of binary operations Relational algebra operations Examples Equivalent transformation and optimization of relational algebra expressions

Слайд 3


Query languages Language categories: procedural (HOW to receive) nonprocedural (WHAT to receive) Formal languages: relational algebra relational calculus (tuple-oriented and domain-oriented)
Описание слайда:
Query languages Language categories: procedural (HOW to receive) nonprocedural (WHAT to receive) Formal languages: relational algebra relational calculus (tuple-oriented and domain-oriented)

Слайд 4


Relational algebra closure and properties of binary operations Property of binary relations: Operation  is commutative if А  В = B  A Operation  is associative if (А  В)  С = А  (В  С) Operation  is distributive with respect with other operation , if А  (В  С ) = (А  В)  (А  С)
Описание слайда:
Relational algebra closure and properties of binary operations Property of binary relations: Operation  is commutative if А  В = B  A Operation  is associative if (А  В)  С = А  (В  С) Operation  is distributive with respect with other operation , if А  (В  С ) = (А  В)  (А  С)

Слайд 5


Relational algebra operations Basic operations: set-theoretic (union, intersection, difference) projection selection cartesian product, join division Additional operations assignment renaming generalized projection outer join …
Описание слайда:
Relational algebra operations Basic operations: set-theoretic (union, intersection, difference) projection selection cartesian product, join division Additional operations assignment renaming generalized projection outer join …

Слайд 6


Set-theoretic operations
Описание слайда:
Set-theoretic operations

Слайд 7


Union operation
Описание слайда:
Union operation

Слайд 8


Difference operation
Описание слайда:
Difference operation

Слайд 9


Intersection operation
Описание слайда:
Intersection operation

Слайд 10


Projection operation
Описание слайда:
Projection operation

Слайд 11


-comparability of attributes and tuples
Описание слайда:
-comparability of attributes and tuples

Слайд 12


Selection (restriction) operation
Описание слайда:
Selection (restriction) operation

Слайд 13


Cartesian product
Описание слайда:
Cartesian product

Слайд 14


Join operation
Описание слайда:
Join operation

Слайд 15


Join and natural join
Описание слайда:
Join and natural join

Слайд 16


Semijoin
Описание слайда:
Semijoin

Слайд 17


Image of the tuple
Описание слайда:
Image of the tuple

Слайд 18


Division operation (1)
Описание слайда:
Division operation (1)

Слайд 19


Division operation(2)
Описание слайда:
Division operation(2)

Слайд 20


Example of DB for RA queries FAC (FNo, Name, Dean, Bld, Fund) DEP (DNo, FNo, Name, Head, Bld, Fund) TCH (TNo, DNo, Name, Post, Tel, Salary, Comm) GRP (GNo, DNo, Course, Num, Quantity, CurNo) SBJ (SNo, Name) ROM (RNo, Num, Building, Seats) LEC (TNo, GNo, SNo, RNo, Type, Day, Week)
Описание слайда:
Example of DB for RA queries FAC (FNo, Name, Dean, Bld, Fund) DEP (DNo, FNo, Name, Head, Bld, Fund) TCH (TNo, DNo, Name, Post, Tel, Salary, Comm) GRP (GNo, DNo, Course, Num, Quantity, CurNo) SBJ (SNo, Name) ROM (RNo, Num, Building, Seats) LEC (TNo, GNo, SNo, RNo, Type, Day, Week)

Слайд 21


Examples of queries in RA (1)
Описание слайда:
Examples of queries in RA (1)

Слайд 22


Examples of queries in RA (2)
Описание слайда:
Examples of queries in RA (2)

Слайд 23


Examples of queries in RA (3)
Описание слайда:
Examples of queries in RA (3)

Слайд 24


Examples of division operation
Описание слайда:
Examples of division operation

Слайд 25


Additional operations Additional operations Assignment Renaming Generalized projection Outer join …
Описание слайда:
Additional operations Additional operations Assignment Renaming Generalized projection Outer join …

Слайд 26


Assignment operation
Описание слайда:
Assignment operation

Слайд 27


Rename operation
Описание слайда:
Rename operation

Слайд 28


Generalized projection operation
Описание слайда:
Generalized projection operation

Слайд 29


Outer join
Описание слайда:
Outer join

Слайд 30


Outer join – example of ordinary join
Описание слайда:
Outer join – example of ordinary join

Слайд 31


Left outer join
Описание слайда:
Left outer join

Слайд 32


Relational Algebra, слайд №32
Описание слайда:

Слайд 33


Full outer join
Описание слайда:
Full outer join

Слайд 34


Equivalent transformations of relational expressions 1) Commutativity of selection: σF(σG(R))=σG(σF(R))=σF&G(R) 2) Commutativity of selection and projection: G(σF(R))=σF(G(R))=σF&G(R), если G  F 3) Distributivity of selection and product σF(R х S) = σF(R) x σF(S) 4) Distributivity of selection and set-theoretic operations: σF(R  S)=σF(R)  σF(S), σF(R  S)=σF(R)  σF(S) 5) Distributivity of selection and join: σF(R S) = σF(R) S, если условие F относится к R 6) Distributivity of projection and set-theoretic operations : F(R  S)=F(R)  F(S), F(R  S)=F(R)  F(S)
Описание слайда:
Equivalent transformations of relational expressions 1) Commutativity of selection: σF(σG(R))=σG(σF(R))=σF&G(R) 2) Commutativity of selection and projection: G(σF(R))=σF(G(R))=σF&G(R), если G  F 3) Distributivity of selection and product σF(R х S) = σF(R) x σF(S) 4) Distributivity of selection and set-theoretic operations: σF(R  S)=σF(R)  σF(S), σF(R  S)=σF(R)  σF(S) 5) Distributivity of selection and join: σF(R S) = σF(R) S, если условие F относится к R 6) Distributivity of projection and set-theoretic operations : F(R  S)=F(R)  F(S), F(R  S)=F(R)  F(S)

Слайд 35


Optimization of RA expressions
Описание слайда:
Optimization of RA expressions

Слайд 36


General rules of RA expressions optimization General rules of RA expressions optimization: Transform each selection σF1&...&Fn(E) to the sequence of selections σF1(... σFn(E)) Move each selection downwards of the tree as far as it is possible (thus (vertical) size of the relation is reduced). Adjacent selection and cartesian product are replaced by join. Move each projection downwards of the tree as far as it is possible (thus (horizontal) size of the relation is reduced). Transform each cascade of adjacent selections and projections into single projection or selection with subsequent projection
Описание слайда:
General rules of RA expressions optimization General rules of RA expressions optimization: Transform each selection σF1&...&Fn(E) to the sequence of selections σF1(... σFn(E)) Move each selection downwards of the tree as far as it is possible (thus (vertical) size of the relation is reduced). Adjacent selection and cartesian product are replaced by join. Move each projection downwards of the tree as far as it is possible (thus (horizontal) size of the relation is reduced). Transform each cascade of adjacent selections and projections into single projection or selection with subsequent projection

Слайд 37


Relational Algebra: Summary Relational Algebra: Formal language for handling data in relational model Procedural language, how to retrieve data No practical relevance for querying DB Formal basis for query optimization Important terms & concepts: Union R  S, difference R – S, intersection R  S Projection <attribute list>(R) Selection σ<predicate>(R) Cartesian product R x S Joins R <predicate> S Difference
Описание слайда:
Relational Algebra: Summary Relational Algebra: Formal language for handling data in relational model Procedural language, how to retrieve data No practical relevance for querying DB Formal basis for query optimization Important terms & concepts: Union R  S, difference R – S, intersection R  S Projection <attribute list>(R) Selection σ<predicate>(R) Cartesian product R x S Joins R <predicate> S Difference

Скачать

Теги Relational Algebra
Похожие презентации
Mypresentation.ru
Загрузить презентацию