Technology Questions

IUnknown as an interface of a COM object. Every COM object has to support IUnknown, besides optionally adding other interfaces.

IUnknown is made of QueryInterface, AddRef and Release.

Oracle Real Application Clusters (RAC) is a software component we can add to a high-availability solution that enables users on multiple machines to access a single database with increased performance. RAC comprises two or more Oracle database instances running on two or more clustered machines and accessing a shared storage device via cluster technology. To support this architecture, the machines that host the database instances are linked by a high-speed interconnect to form the cluster. Oracle RAC offers features in the following areas:

- Scalability

- Availability

- Load balancing

- Failover

To insert a NULL, move -1 to the null indicator

To insert a valid value, move 0 to the null indicator

.Net allows developers to write program logic in at least 25 languages. The classes written in one language can be used by other languages in .Net. This service of .Net is possible through CTS which ensure the rules related to data types that all language must follow. It provides set of types that are used by all .NET languages and ensures .NET language type compatibility.

Android Application Architecture has the following components:
* Services – like Network Operation
* Intent - To perform inter-communication between activities or services
* Resource Externalization - such as strings and graphics
* Notification signaling users - light, sound, icon, notification, dialog etc.
* Content Providers - They share data between applications

<?php
$file = fopen("file.txt","r");
?>

Generating random passwords in PHP can be done in multiple ways depending on how much security the application demands:-

Md5 function can be passed one parameter as uniqid() function which in turn generates a random number. Passing the parameter as TRUE in uniqid() adds additional uniqueness.

<?php
   $passwd = md5(uniqid(rand(), true));
   Echo $passwd;
?>

User defined data-types in SQL is an extension to the base SQL server data-types by provision of a descriptive name.

We use them to format the database and segregate specific repetitions of rows and columns in the database.