CHAPTER 7 Database: SQL, MySQL

Topics  Introduction  Relational Database Model  Relational Database Overview: Books.mdb Database  SQL (Structured Query Language)Basic SELECT Query  WHERE Clause  ORDER BY Clause  Merging Data from Multiple Tables: INNER JOIN  Joining Data from Tables Authors, AuthorISBN, Titles and Publishers  INSERT Statement  UPDATE Statement  DELETE Statement

Introduction Database –Integrated collection of data –Database management system (DBMS) Store and organize data consistent with database’s format Relational database –SQL (Structured Query Language) »Queries »Manipulate data

Relational Database Model Composed of tables Row –Number column –Primary key Reference data in the table A column or set of columns in table contains unique data

Relational Database Model 5 Fig. 22.1Relational database structure of an Employee table.

6 Relational Database Model departmentlocation 413New Jersey 642Los Angeles 611Orlando Fig. 22.2Table formed by selecting department and location data from the Employee table.

Relational Database Model Primary key uniquely identifies each row –Rule of Entity Integrity Composite primary key Lines connecting tables –Relationships One-to-many relationship Foreign key –Join multiple tables –Rule of Referential Integrity

8 Employee Staff_IDNameDepartment 123AhmadGraphic 456ArdenHR 789ZikryEngineering 222SafiaEngineering 111HendraFinance Department Graphic HR Engineering Finance Primary Key Foreign Key When these two tables are linked, Department is a foreign key in table Employee. Data in Department column may be repeatable. Department is a primary key in table Department. Data in Department column must be unique.

9 Relational Database Overview: Books.mdb Database

10 Relational Database Overview: Books.mdb Database

11 Relational Database Overview: Books.mdb Database

12 Relational Database Overview: Books.mdb Database

13 Relational Database Overview: Books.mdb Database

14 Relational Database Overview: Books.mdb Database

15 Relational Database Overview: Books.mdb Database Fig Table relationships in Books.mdb Foreign key- can appears many times in its own table Appears exactly once as primary key of other table

16 SQL (Structured Query Language)

17 Basic SELECT Query SELECT * FROM tableName –SELECT * FROM Authors –SELECT authorID, lastName FROM Authors

18 Basic SELECT Query

19 WHERE Clause Specify selection criteria for query –SELECT columnName1, columnName2, … FROM tableName WHERE criteria SELECT title, editionNumber, copyright FROM Titles WHERE copyright > 1999 –LIKE Pattern matching –Asterisk ( * ) »SELECT authorID, firstName, lastName FROM Authors WHERE lastName LIKE ‘D*’ –Question mark ( ? ) »SELECT authorID, firstName, lastName FROM Authors WHERE lastName LIKE ‘?I*’

20 WHERE Clause

21 WHERE Clause

22 WHERE Clause

23 ORDER BY Clause Arranged in ascending or descending order –SELECT columnName1, columnName2, … FROM tableName ORDER BY column ASC SELECT authorID, firstName, lastName FROM Authors ORDER BY lastName ASC –SELECT columnName1, columnName2, … FROM tableName ORDER BY column DESC SELECT authorID, firstName, lastName FROM Authors ORDER BY lastName DESC

24 ORDER BY Clause

25 ORDER BY Clause

26 ORDER BY Clause SELECT authorID, firstName, lastName FROM Authors ORDER BY lastName, firstName

27 ORDER BY Clause

28 ORDER BY Clause SELECT isbn, title, editionNumber, copyright, price FROM Titles WHERE title LIKE ‘*How to Program’ ORDER BY title ASC

29 Merging Data from Multiple Tables: INNER JOIN Normalize databases –Ensure database does not store data redundantly –SELECT columnName1, columnName2, … FROM table1 INNER JOIN table2 ON table1, columnName = table2.columnName –SELECT firstName, lastName, isbn FROM Authors INNER JOIN AuthorISBN ON Authors.authorID = AuthorISBN.authorID ORDER BY lastName, firstName

30 Merging Data from Multiple Tables: INNER JOIN

31 Fig (1 of 1)

32 Joining Data from Tables Authors, AuthorISBN, Titles and Publishers

33 Joining Data from Tables Authors, AuthorISBN, Titles and Publishers

34 INSERT Statement Inserts new row in table –INSERT INTO tableName ( columnName1, columnName2, …, columnNameN ) VALUES ( value1, value2, …, valueN ) –INSERT INTO Authors ( firstName, lastName ) VALUES ( ‘Sue’, ‘Smith’ )

35 INSERT Statement

36 UPDATE Statement Modifies data in a table –UPDATE tableName SET columnName1 = value1, columnName2 = value2, …, columnNameN = valueN WHERE criteria –UPDATE Authors SET lastName = ‘Jones’ WHERE lastName= ‘Smith’ AND lastName=‘Sue’

37 UPDATE Statement

38 DELETE Statement Removes data from a table –DELETE FROM tableName WHERE criteria –DELETE FROM Authors WHERE lastName=‘Jones’ AND firstName=‘Sue’

39 DELETE Statement

40 MySQL Multi-user and multi-threaded RDBMS server Uses SQL to interact with and manipulate data Supports various programming languages Access tables from different databases Handle large databases The next chapter explains the usage of MySQL with PHP.