by define() directive,
like define (“MYCONSTANT”, 500);
like define (“MYCONSTANT”, 500);
THE DIFFERENT TYPES OF ERRORS IN PHP?
PMA00:26
1. Notices: These are trivial, non-critical errors that PHP
encounters while executing a script – for example, accessing a variable
that has not yet been defined
2. Warnings: These are more serious errors – for example, attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.
3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP’s default behavior is to display them to the user when they take place.
Internally, these variations are represented by twelve different error types
2. Warnings: These are more serious errors – for example, attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.
3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP’s default behavior is to display them to the user when they take place.
Internally, these variations are represented by twelve different error types
What’s the special meaning of __sleep and __wakeup?
PMA00:25
__sleep returns the array of all the variables than need to be saved,
while __wakeup retrieves them.
while __wakeup retrieves them.
What is the difference between $age and $$age
PMA00:24
They are both variables. But $age is a variable with a fixed name.
$$age is a variable who’s name is stored in $age. For example,
if $age contains “var”, $$age is the same as $var.
$test = ‘abcd';
is equivalent to
$holder = ‘test';
$$holder = ‘abcd';
$test = ‘abcd';
is equivalent to
$holder = ‘test';
$$holder = ‘abcd';
How many values can the SET function of MySQL take?
PMA22:42
MySQL set can take zero or more values but at the maximum it can
take 64 values
take 64 values
What is the maximum size of a file that can be uploaded using PHP and how can we change this?
PMA22:41
By default the maximum size is 2MB.
can change the size
setup at php.ini
upload_max_filesize = 12M
can change the size
setup at php.ini
upload_max_filesize = 12M
How can we encrypt the username and password using PHP?
PMA22:38
The functions in this section perform encryption and decryption
| encryption | decryption |
| AES_ENCRYT() | AES_DECRYPT() |
| ENCODE() | DECODE() |
| DES_ENCRYPT() | DES_DECRYPT() |
| ENCRYPT() | Not available |
| MD5() | Not available |
| OLD_PASSWORD() | Not available |
| PASSWORD() | Not available |
| SHA() or SHA1() | Not available |
| Not available | UNCOMPRESSED_LENGTH() |
count the elements of an array?
PMA22:37
sizeof($array) – This function is an alias of count()
count($urarray) – This function returns the number of elements in an array.
count($urarray) – This function returns the number of elements in an array.