PHP interview questions

PHP Questions : 1 How many ways we can pass the variable through the navigation
between the pages?
Answer : 
  • GET/QueryString
  • POST
Questions : 2 What is the difference between ereg_replace() and eregi_replace()?
Answer :  eregi_replace() function is identical to ereg_replace() except that
this ignores case distinction when matching alphabetic
characters.eregi_replace() function is identical to ereg_replace()
except that this ignores case distinction when matching alphabetic
characters.
Questions : 3 What are the different functions in sorting an array?
Answer :  Sort(), arsort(),
asort(), ksort(),
natsort(), natcasesort(),
rsort(), usort(),
array_multisort(), and
uksort().
Questions : 4 How can we know the count/number of elements of an array?
Answer :  2 ways
a) sizeof($urarray) This function is an alias of count()
b) count($urarray)
Questions : 5 what is session_set_save_handler in PHP?
Answer :  session_set_save_handler() sets the user-level session storage functions which are used for storing and retrieving data associated with a session. This is most useful when a storage method other than those supplied by PHP sessions is preferred. i.e. Storing the session data in a local database.
Questions : 6 How can I know that a variable is a number or not using a
JavaScript?
Answer :  bool is_numeric ( mixed var)
Returns TRUE if var is a number or a numeric string, FALSE otherwise.or use isNaN(mixed var)The isNaN() function is used to check if a value is not a number.
Questions : 7 List out some tools through which we can draw E-R diagrams for
mysql.
Answer :  Case Studio
Smart Draw
Questions : 8 How can I retrieve values from one database server and store them
in other database server using PHP?
Answer :  we can always fetch from one database and rewrite to another. here
is a nice solution of it.$db1 = mysql_connect(“host”,”user”,”pwd”)
mysql_select_db(“db1”, $db1);
$res1 = mysql_query(“query”,$db1);$db2 = mysql_connect(“host”,”user”,”pwd”)
mysql_select_db(“db2”, $db2);
$res2 = mysql_query(“query”,$db2);At this point you can only fetch records from you previous ResultSet,
i.e $res1 – But you cannot execute new query in $db1, even if you
supply the link as because the link was overwritten by the new db.so at this point the following script will fail
$res3 = mysql_query(“query”,$db1); //this will failSo how to solve that? take a look below.
$db1 = mysql_connect(“host”,”user”,”pwd”)
mysql_select_db(“db1”, $db1);
$res1 = mysql_query(“query”,$db1);
$db2 = mysql_connect(“host”,”user”,”pwd”, true)
mysql_select_db(“db2”, $db2);
$res2 = mysql_query(“query”,$db2);
So mysql_connect has another optional boolean parameter which
indicates whether a link will be created or not. as we connect to the
$db2 with this optional parameter set to ‘true’, so both link will
remain live.
now the following query will execute successfully.
$res3 = mysql_query(“query”,$db1);
Questions : 9 List out the predefined classes in PHP?
Answer :  Directory
stdClass
__PHP_Incomplete_Class
exception
php_user_filter
Questions : 10 How can I make a script that can be bi-language (supports
English, German)?
Answer :  You can maintain two separate language file for each of the
language. all the labels are putted in both language files as variables
and assign those variables in the PHP source. on runtime choose the
required language option.
Questions : 11 What are the difference between abstract class and interface?
Answer :  Abstract class: abstract classes are the class where one or more
methods are abstract but not necessarily all method has to be abstract.
Abstract methods are the methods, which are declare in its class but not
define. The definition of those methods must be in its extending class.Interface: Interfaces are one type of class where all the methods are
abstract. That means all the methods only declared but not defined. All
the methods must be define by its implemented class.
Questions : 12 How can we send mail using JavaScript?
Answer :  JavaScript does not have any networking capabilities as it is
designed to work on client site. As a result we can not send mails using
JavaScript. But we can call the client side mail protocol mailto
via JavaScript to prompt for an email to send. this requires the client
to approve it.
Questions : 13 How can we repair a MySQL table?
Answer :  The syntex for repairing a MySQL table is
REPAIR TABLENAME, [TABLENAME, ], [Quick],[Extended]
This command will repair the table specified if the quick is given the
MySQL will do a repair of only the index tree if the extended is given
it will create index row by row
Questions : 14 What are the advantages of stored procedures, triggers, indexes?
Answer :  A stored procedure is a set of SQL commands that can be compiled and
stored in the server. Once this has been done, clients don’t need to
keep re-issuing the entire query but can refer to the stored procedure.
This provides better overall performance because the query has to be
parsed only once, and less information needs to be sent between the
server and the client. You can also raise the conceptual level by having
libraries of functions in the server. However, stored procedures of
course do increase the load on the database server system, as more of
the work is done on the server side and less on the client (application)
side.Triggers will also be implemented. A trigger is effectively a type of
stored procedure, one that is invoked when a particular event occurs.
For example, you can install a stored procedure that is triggered each
time a record is deleted from a transaction table and that stored
procedure automatically deletes the corresponding customer from a
customer table when all his transactions are deleted.Indexes are used to find rows with specific column values quickly.
Without an index, MySQL must begin with the first row and then read
through the entire table to find the relevant rows. The larger the
table, the more this costs. If the table has an index for the columns in
question, MySQL can quickly determine the position to seek to in the
middle of the data file without having to look at all the data. If a
table has 1,000 rows, this is at least 100 times faster than reading
sequentially. If you need to access most of the rows, it is faster to
read sequentially, because this minimizes disk seeks.
Questions : 15 What is the maximum length of a table name, database name, and
fieldname in MySQL?
Answer :  The following table describes the maximum length for each type of
identifier.

Identifier Maximum Length
(bytes)
Database 64
Table 64
Column 64
Index 64
Alias 255

There are some restrictions on the characters that may appear in
identifiers:

 

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