Presentación de Bases de datos

Introducción a las bases de datos
SQL
1
Libro de referencia
Java How To Program 3ed Edition
Deitel&Deitel
Prentice Hall, 1999
2
%DVHVGHGDWRV
Ɣ Introduction
Ɣ Relational-Database Model
Ɣ Relational Database Overview: The books Database
Ɣ SQL
3
Introduction
• Database
– Collection of data
• DBMS
– Database management system
– Stores and organizes data
• RDBMS
– Relational database management system
– Tables
4
Introduction (Cont.)
• SQL
– Relational database
– Structured Query Language
5
DB Major Tasks
• Defining Databases - involves specifying the data
types, structures, and constraints for the data to be
stored in the database.
• Constructing Databases - storing the data itself
(populating) on some storage medium that is
controlled by the DBMS.
• Manipulating Databases - querying the database to
retrieve specific data, updating the databases, and
generating reports from the data.
6
Database Languages
DDL Data Definition Language
Provides facilities for definining database objects.
DML Data manipulation Language
Provides features for specifying the processing to
be performed on database objects.
SQL provides both
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Application Architectures
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Relational Model
• Relational database
– Table
• Rows, columns
– Primary key
• Unique data
• SQL statement
– Query
9
Tables
Authors
Author
ID
FirstName
LastName
YearBorn
1
Harvey
Deitel
1946
2
Paul
Deitel
1968
3
Tem
Nieto
1969
10
Redundant Table
AuthorID
FirstName
LastName
YearBorn
ISBN
1
Harvey
Deitel
1946
0-13-010671-2
2
Paul
Deitel
1968
0-13-010671-2
1
Harvey
Deitel
1946
0-13-020522-2
2
Paul
Deitel
1968
0-13-020522-2
3
Tem
Nieto
1969
0-13-020522-2
11
Related Tables
Authors
Author
ID
FirstName
LastName
YearBorn
1
Harvey
Deitel
1946
2
Paul
Deitel
1968
3
Tem
Nieto
1969
ISBN
AuthorISBN
0-13-010671-2
0-13-010671-2
0-13-020522-2
0-13-020522-2
0-13-020522-2
Author
ID
1
2
1
2
3
12
Relational Database
A primary key is a column or set of columns that uniquely
identifies the rest of the data in any given row.
A foreign key is a column in a table where that column is a
primary key of another table.
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Relational Operations
Projection
VLG
VQDPH UDWLQJ DJH
\XSS\
OXEEHU JXSS\
UXVW\
sname
rating
yuppy
lubber
guppy
rusty
9
8
5
10
14
Projection
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Relational Operations
Selection
VLG
VQDPH UDWLQJ DJH
\XSS\
OXEEHU JXSS\
UXVW\
sname rating
yuppy 9
rusty
10
Rating > 8
16
Relational Operations
Join
VLG
VLG ELG
GD\
VQDPH UDWLQJ DJH
GXVWLQ
OXEEHU UXVW\
sid
22
58
sname rating age
dustin 7
45.0
rusty
10
35.0
bid
101
103
day
10/10/96
11/12/96
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Join Types
Inner Join
Only the rows that match the search conditions are returned
Left Outer Join
Returns all matched rows, plus all unmatched rows from the table on
the left of the join clause (use nulls in fields of non-matching tuples)
Right Outer Join
Returns all matched rows, plus all unmatched rows from the table on
the right of the join clause
Full Outer Join
Returns all (matched or unmatched) rows from the tables on both
sides of the join clause
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Books Database
• Sample ERRNV database
– Four tables
‡ $XWKRUV, 3XEOLVKHUV, $XWKRU,6%1 and
7LWOHV
– Relationships among the tables
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Tabla Authors de la base de datos Books
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Datos de la tabla Authors
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Tabla Publishers
22
Datos de la tabla Publishers
23
Tabla AuthorISBN
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Datos de la tabla AuthorISBN (parcial)
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Tabla Titles
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Datos de la tabla Titles (parcial)
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Table Relationships
authors
authorID
firstName
1
’
authorISBN
authorID
isbn
1
’
titles
isbn
title
lastName
editionNumber
publishers
publisherID
publisherName
’
1
copyright
publisherID
imageFile
price
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Comandos SQL
SQL keyword
Description
CREATE TABLE
Creates a table.
SELECT
Retrieves data from one or more tables.
FROM
Tables involved in the query. Required in every
SELECT.
WHERE
Criteria for selection that determine the rows to be
retrieved, deleted or updated.
GROUP BY
Criteria for grouping rows
ORDER BY
INNER JOIN
Criteria for ordering rows.
Merge rows from multiple tables.
INSERT
Insert rows into a specified table.
UPDATE
Update rows in a specified table.
DELETE
Delete rows from a specified table.
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Query SELECT
• Simplest form of a SELECT query
– SELECT * FROM tableName
• SELECT * FROM authors
• Select specific fields from a table (projection)
– SELECT authorID, lastName FROM authors
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WHERE Clause
• specify the selection criteria
– SELECT columnName1, columnName2, … FROM tableName
WHERE criteria
• SELECT title, editionNumber, YearPublished
FROM titles
WHERE YearPublished > '1998'
• WHERE clause condition operators
<, >, <=, >=, =, <>
LIKE
wildcard characters % and _
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AuthorID y apellido
SELECT authorID, lastName FROM Authors
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Autores nacidos despues de 1960
SELECT * FROM Authors WHERE YearBorn > '1960'
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Autores cuyos apellidos empiezan con d
SELECT * FROM Authors WHERE LastName LIKE 'd%'
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Autores cuyo nombre tiene i como segunda
letra
SELECT * FROM Authors WHERE LastName LIKE '_i%'
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Tabla Authors ordenada por apellido en orden
ascendente
SELECT * FROM Authors ORDER BY LastName ASC
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Tabla Authors ordenada por apellido en orden
descendente
SELECT * FROM Authors ORDER BY LastName DESC
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Tabla Authors ordenada por apellido y luego
por nombre en orden ascendente
SELECT * FROM Authors ORDER BY LastName, FirstName ASC
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Libros de Titles cuyos títulos terminan en How to
program ordenados en forma ascendente con respecto
al título
SELECT * FROM Titles
WHERE Title LIKE '%How to Program'
ORDER BY Title ASC
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Combinar los datos de multiples tablas: JOIN
• Join the tables
– Merge data from multiple tables into a single view
– INNER JOIN
• SELECT columnName1, columnName2, …
FROM (table1 INNER JOIN table2)
ON table1.columnName = table2.column2Name
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Combinar los datos de multiples tablas: JOIN
Authors
AuthorISBN
Author
ID
FirstName
LastName
YearBorn
ISBN
1
Harvey
Deitel
1946
2
Paul
Deitel
1968
3
Tem
Nieto
1969
0-13-010671-2
0-13-010671-2
0-13-020522-2
0-13-020522-2
0-13-020522-2
Author
ID
1
2
1
2
3
SELECT Authors.AuthorID, FirstName, LastName, YearBorn, ISBN
FROM Authors INNER JOIN AuthorISBN
ON Authors.AuthorID=AuthorISBN.AuthorID
41
Combinar los datos de multiples tablas: JOIN
AuthorID
FirstName
LastName
YearBorn
ISBN
1
Harvey
Deitel
1946
0-13-010671-2
1
Harvey
Deitel
1946
0-13-010671-2
2
Paul
Deitel
1968
0-13-020522-2
2
Paul
Nieto
1968
0-13-020522-2
3
Tem
Nieto
1969
0-13-020522-2
42
Autores y los ISBN de los libros que
escribieron en orden ascendente por apellido y
por nombre
SELECT FirstName, LastName, ISBN
FROM Authors INNER JOIN AuthorISBN
ON Authors.AuthorID=AuthorISBN.AuthorID
ORDER BY LastName, FirstName
43
Query TitleAuthor incluida en la base de datos
SELECT
Titles.Title, Titles.ISBN, Authors.FirstName,
Authors.LastName, Titles.YearPublished,
Publishers.PublisherName
FROM
(Publishers INNER JOIN Titles ON
Publishers.PublisherID = Titles.PublisherID)
INNER JOIN
(Authors INNER JOIN AuthorISBN ON
Authors.AuthorID = AuthorISBN.AuthorID)
ON
Titles.ISBN = AuthorISBN.ISBN
ORDER BY Titles.Title
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Ejecución del Query TitleAuthor
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UPDATE
UPDATE table_name
SET column_name = new_value
WHERE column_name = some_value
Ejemplo
UPDATE Authors
SET FirstName = 'Juan'
WHERE FirstName = 'Tem'
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INSERT INTO
INSERT INTO table_name
VALUES (value1, value2, …)
Ejemplo
INSERT INTO Authors
VALUES (4, 'bart', 'simpson', '1990')
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DELETE
DELETE FROM table_name
WHERE column_name = some_value
Ejemplo
DELETE FROM Authors
WHERE FirstName= 'bart'
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