7/30/2019 PHP_part_1

1/14

2008 Pearson Education, Inc. All rights reserved.

1

23

PHP

http://www.uml.org/

7/30/2019 PHP_part_1

2/14

2008 Pearson Education, Inc. All rights reserved.

2

23.1 Introduction

23.2 PHP Basics

23.3 String Processing and Regular Expressions23.3.1 Comparing Strings

23.3.2 Regular Expressions

23.4 Form Processing and Business Logic

23.5 Connecting to a Database

23.6 Using Cookies

23.7 Dynamic Content

23.8 Operator Precedence Chart

23.9 Wrap-Up

23.10 Web Resources

http://www.uml.org/

7/30/2019 PHP_part_1

3/14

2008 Pearson Education, Inc. All rights reserved.

3

23.1 Introduction

PHP, or PHP: Hypertext Preprocessor, hasbecome one of the most popular server-side

scripting languages for creating dynamic web

pages.

PHP is open source and platform independent

implementations exist for all major UNIX, Linux,

Mac and Windows operating systems. PHP also

supports a large number of databases.

http://www.uml.org/

7/30/2019 PHP_part_1

4/14

2008 Pearson Education, Inc. All rights reserved.

4

23.2 PHP Basics

The power of the web resides not only in serving content to users, butalso in responding to requests from users and generating web pageswith dynamic content.

PHP code is embedded directly into XHTML documents, thoughthese script segments are interpreted by a server before beingdelivered to the client.

PHP script file names end with .

In PHP, code is inserted between the scripting delimiters and. PHP code can be placed anywhere in XHTML markup, as long as

the code is enclosed in these delimiters.

http://www.uml.org/

7/30/2019 PHP_part_1

5/14

2008 Pearson Education, Inc. All rights reserved.

5

23.2 PHP Basics (Cont.)

Variables are preceded by a and are created the first time they areencountered.

PHP statements terminate with a semicolon ( ).

Single-line comments which begin with two forward slashes ( ) or apound sign ( ). Text to the right of the delimiter is ignored by theinterpreter. Multiline comments begin with delimiter and end withdelimiter .

When a variable is encountered inside a double-quoted ( ) string,PHP interpolates the variable. In other words, PHP inserts thevariables value where the variable name appears in the string.

All operations requiring PHP interpolation execute on the server

before the XHTML document is sent to the client.

http://www.uml.org/

7/30/2019 PHP_part_1

6/14

2008 Pearson Education,Inc. All rights reserved.

61

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

Outline

Delimiters

enclosing PHP

script

Declares and

initializes a PHP

variable

Interpolates the variable

so that its value will be

output to the XHTML

document

http://www.uml.org/

7/30/2019 PHP_part_1

7/14 2008 Pearson Education, Inc. All rights reserved.

7

23.2 PHP Basics (Cont.)

Type conversions can be performed using function. This function takes two argumentsa variablewhose type is to be changed and the variables new type.

Function returns the current type of itsargument.

Calling function can result in loss of data. Forexample, doubles are truncated when they are convertedto integers.

When converting from a string to a number, PHP uses thevalue of the number that appears at the beginning of the

string. If no number appears at the beginning, the stringevaluates to .

The concatenation operator ( ) combines multiple strings.

http://www.uml.org/

7/30/2019 PHP_part_1

8/14

2008 Pearson Education,Inc. All rights reserved.

81

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

Outline

(1 of 3)

Automatically declares a string

Automatically declares a double

Automatically declares an integer

Outputs the type of$testString

23

http://www.uml.org/

7/30/2019 PHP_part_1

9/14

2008 Pearson Education,Inc. All rights reserved.

923

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

Outline

(2 of 3)

Modifies $testString

to be a double

Modifies $testString

to be an integerModifies $testString

to be a string

43

http://www.uml.org/

7/30/2019 PHP_part_1

10/14

2008 Pearson Education,Inc. All rights reserved.

1043

44

45

46

47

48

49

50

51

52

53

54

Outline

(3 of 3)

Temporarily casts

$data as a double

and an integer

Concatenation

http://www.uml.org/

7/30/2019 PHP_part_1

11/14 2008 Pearson Education, Inc. All rights reserved.

11

23.2 PHP Basics (Cont.)

Function creates a named constant. It takes twoargumentsthe name and value of the constant. An

optional third argument accepts a boolean value that

specifies whether the constant is case insensitive

constants are case sensitive by default.

Uninitialized variables have the value , which has

different values, depending on its context. In a numeric

context, it evaluates to . In a string context, it evaluates

to an empty string ( ).

1

http://www.uml.org/

7/30/2019 PHP_part_1

12/14

2008 Pearson Education,Inc. All rights reserved.

121

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Outline

(1 of 3)

Creates the namedconstant VALUE with a

value of 5

Equivalent to $a = $a * 2

1328

http://www.uml.org/

7/30/2019 PHP_part_1

13/14

2008 Pearson Education,Inc. All rights reserved.

1328

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

Outline

(2 of 3)Uses a comparison operatorwith a variable and an integer

Uninitialized variable$num evaluates to 0

1453

http://www.uml.org/

7/30/2019 PHP_part_1

14/14

2008 Pearson Education,Inc. All rights reserved.

1453

54

55

56

57

58

59

60

61

62

Outline

(3 of 3)

$str is converted to an

integer for this operation

http://www.uml.org/