Interview Questions

Constraints enable the RDBMS to enforce the integrity of the database automatically, without the need to create triggers, rule or defaults.

Types of Constraints: NOT NULL, CHEQUE, UNIQUE, PRIMARY KEY, FOREIGN KEY.

array_flip exchange the keys with their associated values in array ie. Keys becomes values and values becomes keys.

<?php
$arrayName    = array("course1"=>"php","course2"=>"html");
$new_array    = array_flip($arrayName);
print_r($new_array);
?>

OUTPUT :

Array
(
[php]     => course1
[html]    => course2
)

Use case diagram, activity diagram, Collaboration diagram. 

Use case diagram :

It describes the business environment. Its primary goal is to show the series of events and actions within any given process that will be performed by an actor.  

Activity diagram:

The activity diagram is important because it gives an outline of the work flow within the business as well as the activities and action completed. 

For instance with a company, there is likely to be more than one department. In such a case each department, will have different access levels to the system. 

So if there’s a Medical, HR and Accounts team they will only have access to screens that relate to each. 

The activity diagram will highlight the differences within the departments which will be very helpful for developers when they are designing and coding. 

Collaboration diagram:

A collaboration diagram, also called a communication diagram or interaction diagram, is an illustration of the relationships and interactions among software objects in the Unified Modeling Language (UML). The concept is more than a decade old although it has been refined as modeling paradigms have evolved. 

Wrapping is also called as packing or boxing.

Storing the data inside the object as private data which can accessed outside the class only by using methods.

There are mainly four type of JDBC drivers available. They are:

Type 1 : JDBC-ODBC Bridge Driver - A JDBC-ODBC bridge provides JDBC API access via one or more ODBC drivers. Note that some ODBC native code and in many cases native database client code must be loaded on each client machine that uses this type of driver. Hence, this kind of driver is generally most appropriate when automatic installation and downloading of a Java technology application is not important. For information on the JDBC-ODBC bridge driver provided by Sun.

Type 2: Native API Partly Java Driver- A native-API partly Java technology-enabled driver converts JDBC calls into calls on the client API for Oracle, Sybase, Informix, DB2, or other DBMS. Note that, like the bridge driver, this style of driver requires that some binary code be loaded on each client machine.

Type 3: Network protocol Driver- A net-protocol fully Java technology-enabled driver translates JDBC API calls into a DBMS-independent net protocol which is then translated to a DBMS protocol by a server. This net server middleware is able to connect all of its Java technology-based clients to many different databases. The specific protocol used depends on the vendor. In general, this is the most flexible JDBC API alternative. It is likely that all vendors of this solution will provide products suitable for Intranet use. In order for these products to also support Internet access they must handle the additional requirements for security, access through firewalls, etc., that the Web imposes. Several vendors are adding JDBC technology-based drivers to their existing database middleware products.

Type 4: JDBC Net pure Java Driver - A native-protocol fully Java technology-enabled driver converts JDBC technology calls into the network protocol used by DBMSs directly. This allows a direct call from the client machine to the DBMS server and is a practical solution for Intranet access. Since many of these protocols are proprietary the database vendors themselves will be the primary source for this style of driver. Several database vendors have these in progress.

All my bosses enchanted some skills worth learning. I have always used to learn something new from them along with my ex-boss.

The QA testing process that was followed in my last company where I worked was like this: First of all the Business Requirement Document was prepared as per the client’s requirement (with the muck-up screen shots). Then on the basis of the requirement document, Test Strategy, Test Plans and Test Cases were written in sequential order. Once the Build is made and deployed to the different testing environments where different types of testing were performed to check whether there are any defects.

Depreciation is a process of cost allocation, not valuation. In accounting, the term depreciation refers to the allocation of cost of a tangible asset to expense to the periods in which the asset is expected to be used to obtain the economic benefit.

In brief, Depreciation is fall in the value of assets due to wear and tear over a period of time, it is a loss.