PHP Interview question 14

51) List out some tools through which we can draw E-R diagrams for mysql.

Ans :      Case Studio

Smart Draw

52) How can I retrieve values from one database server and store them in other database server using PHP?

Ans :      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);

53)  List out the predefined classes in PHP?

Ans :      Directory

stdClass

__PHP_Incomplete_Class

exception

php_user_filter

                 

54) How can I make a script that can be bi-language (supports English, German)?

Ans :      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.

55) What are the difference between abstract class and interface?

Ans :      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.