Lecture 9 - Stateful Web

Question 1

What does PDO stand for?

Answer 1

PHP Data Object

Question 2

To configure the PDO to throw an exception any time there’s a failure?

Answer 2

Use the PDO’s setAttribute() method

Question 3

What is the exec() method used for?

Answer 3

Queries can be sent to a MYSQL database using it.

Question 4

What does PDO do?

Answer 4

Identifies that the connection to a database has been established

Question 5

If PHP cannot handle PDO, what will it do?

Answer 5

Throws a php exception

Question 6

What does the try-catch statement do?

Answer 6

try {
do something
}
catch (Exception type $e){
handle exception
}

Question 7

What does this code do?

Answer 7

This function returns a PHP Data Object (PDO)

Question 8

IF this PDO code can’t be performed, what happens?

Answer 8

PHP will throw an exception

Question 9

What does PHP do with a database once a connection is no longer needed?

Answer 9

It automatically disconnects

Question 10

How do you force PHP to close a connection?

Answer 10

$pdo = null

Question 11

How do you connect to a database with procedural php?

Answer 11

$variable_name = mysql_connect(hostname, username, password);

Question 12

How do you close a connection to a mysql database with procedural php?

Answer 12

mysql_close();

Question 13

What must be do before answering a query?

Answer 13

Establish a database connection

Question 14

What are the best practices of querying a database?

Answer 14

Establish a connection at the start of the php script

During development, leave clues in case of issues when passing queries to the server. (relevant error messages)

Question 15

Name three sql queries

Answer 15

DELETE, INSERT, UPDATE

Question 16

PDO Method: How do we create a table?

Answer 16

$sql = ‘CREATE TABLE jokes(id INT NOT NULLAUTO_INCREMENT PRIMARY KEY,
joketext TEXT,
jokedate DATE NOT NULL,
)

$pdo->exec($sql)

Question 17

PDO Method: How do we update a table?

Answer 17

$sql = ‘UPDATE joke SET jokedate = “2012” WHERE joke text LIKE “%chicken%”;

$affectedRows = $pdo ->exec($sql)

Question 18

PDO Method: How do we SELECT?

Answer 18

$sql = 'SELECT * FROM tablename'; 
$result = $pdo->query($sql);

Question 19

What makes SELECT queries different from other queries?

Answer 19

They produce results

Question 20

Procedural Method: How do we send SQL queries through php?

Answer 20

$variable_name = mysqli_query(sql statement);

Example:
$variable_name = mysqli_query(SELECT*FROM customers);

Question 21

What would the result set of a query contain?

Answer 21

A list of all the entries returned from the query

Question 22

Which PHP functions are needed to connect to the database using procedural php?

Answer 22

mysqli_connect()
mysql_set_chart()
mysqli_select_db()

Question 23

What does mysqli_connect() do?

Answer 23

Connects to the database

Question 24

What does mysql_set_chartset() do?

Answer 24

Indicates the character set to be used for
communications between PHP and the DB

Must match the character set used by HTML pages,
DB and its tables

Question 25

What does mysql_select_db() do?

Answer 25

Indicates the database to be used for queries.

Question 26

How would you add a new joke from a user, using php?

Answer 26

if (isset($_GET['addjoke'])) { include 'form.html.php'; exit()

Question 27

When deleting a record, how will we identify which once we want removed?

Answer 27

By it's ID

Question 28

Can vars in the main script be accessed or edited from an included file?

Answer 28

Yes. is can cause issues likes overwrites. Functions can protect you from this happening.

Question 29

What is a function's scope?

Answer 29

Variables created inside a function exist only in that function

Question 30

Can vars from the mains script by accessed from within functions?

Answer 30

No.

Question 31

How can we mitigate issues that function and global variable scope can cause?

Answer 31

Keep track of var names and scripts Keep track of which variables work within which scripts

Question 32

What are the two ways we can use vars in a function?

Answer 32

Importing a variable using the $GLOBALS array

Question 33

What is the magic quotes function?

Answer 33

- Causes as many issues as it solves - Only works in some circumstances - Functionality depends on site's character encoding - Adds backslashes to escape characters expected in a sql query, even if it's just plain text - We still need to work with it for now

Question 34

How do we import a variable to a function?

Answer 34

Using the global statement you can import more than one variable. If you modify an imported variable inside the function, it's value is modified outside the function.

Question 35

If you edit an imported variable inside a function, is it affected outside the function?

Answer 35

Yes, the value is modified outside the function as well

Question 36

How do we use the $GLOBALS array?

Answer 36

Access with $GLOBALS['variable_name]

Question 37

What is the advantage to using the $GLOBALS array?

Answer 37

Keeps variables with a function scope separate

Question 38

Name some super global arrays

Answer 38

``` $_GET $_POST $_COOKIE $_FILES $_REQUEST $_SERVER $_SESSION $_ENV ```

Question 39

Why do we have a stateful web?

Answer 39

Most programs preserve some state when they are closed. There was a need for similar functionality in dynamic sites

Question 40

What does HTTP stand for?

Answer 40

HyperText Transfer Protocol

Question 41

What is HTTP responsible for?

Answer 41

Handling Requests

Question 42

What are the limitations of HTTP?

Answer 42

It is a stateless technology Provides no user tracking

Question 43

What is the solution to the limitations of HTTP?

Answer 43

Cookies...and cream

Question 44

What is a Php cookie?

Answer 44

A name-value pair associated with a given website

Question 45

Where is a cookie stored?

Answer 45

On the client side and limited to 4kb of data

Question 46

Once the cookie is set, all following requests of the site will include what?

Answer 46

the cookie for that site

Question 47

When does a cookie expire?

Answer 47

When it becomes out of date or the browser is closed.

Question 48

Can cookies be accessed from any website?

Answer 48

Only the website that issued them

Question 49

How do we create a cookie?

Answer 49

Use the setcookie() function

Question 50

Do cookies behave the same way in all browsers?

Answer 50

No

Question 51

What is the one necessary parameter of a cookie?

Answer 51

The name

Question 52

What info will be kept int he cookie?

Answer 52

The value The expiry time

Question 53

How would we set the cookie to expire in one hour

Answer 53

time() + 3600

Question 54

The setcookie() function's domain allows you to:

Answer 54

Restrict the cookie's access to a specific domain.

Question 55

How do we limit the cookie requests to only be sent over a secure connection?

Answer 55

Use 'secure'

Question 56

httpOnly is used for what?

Answer 56

If set to 1, tells browser to prevent JavaSCript code on the site from seeing the cookie being sent

Question 57

What are the limitations of cookies?

Answer 57

Browsers limit the number and size of cookies per website Browsers delete old cookies to make space for new ones

Question 58

What is the max size of a cookie?

Answer 58

4kb

Question 59

What do we use if we need more space than a cookie can provide?

Answer 59

A session

Question 60

What one value is stored in the browser to allow for a session?

Answer 60

The session ID, stored as a cookie.

Question 61

When a session is started, what does PHP generate?

Answer 61

PHP generates a randon session ID, a reference to that session, and its stored data

Question 62

Where is the value of the session set?

Answer 62

The special $_SESSION array

Question 63

What happens if an existing session ID is found when starting a session?

Answer 63

PHP restores the variables that belong to that session

Question 64

How do we set a session variable in the special $_SESSION array?

Answer 64

$ ..._...SESSION... [...' name...'] = value

Question 65

How do we remove a variable from the current session?

Answer 65

unset SESSION name