how database system deal with database applications

May 2, 2010

ANS-The DBMS is an important component of the database environment.

This environment also includes different types of hardware and software,

people who perform different functions within the environment, procedures

designed to accomplish desired activities, and data.

The data constitute the database’s central component through which information is generated.

Let me emphasize that the main purpose of the database environment is to help an organization

to perform its mission and to achieve its goals.

The Database Environment Components

Note that the database administrator writes and enforces the procedures and standards

that are then used by designers, analysts, programmers, and end users.

The end users use the application programs created by analysts and programmers.

Note: Analysts wear two hats. They are end users in that they perform analysis

based on the application programs.

And they help produce application programs by collaborating with programmers

to define the parameters of the applications.

In turn, the application programs make use of the DBMS, which manages the data.

Note also that the database designer and the database administrator perform their jobs

through the interface – that would be shown on the computer.

The interface is the gateway to the database, which resides within the hardware.

Finally, the System Administrator manages the entire system.

The modern database‑and‑applications development software is so easy to use that

many people can quickly learn to implement a simple database and develop simple

applications within a week or so, without giving design a thought.

As data and reporting requirements become more complex,

those same people will simply (and quickly!) produce the required add-ons.

That’s how data redundancies and all their attendant anomalies develop,

thus reducing the “database” and its applications to a status worse than useless.

Good applications can’t overcome bad database designs.

The existence of a DBMS does not guarantee good data management,

nor does it ensure that the database will be able to generate correct and timely information.

Ultimately, the end user and the designer decide what data will be stored in the database.

Since most current DBMSes are based on the relational model, the relational model’s

conceptual simplicity could be compared to the hierarchical and network models.

Because the entity relationship model’s representation – through the ERD –

is the basis for database design.

Database design is a process that, in effect, yields a detailed database blueprint.

This blueprint, usually in the form of an E-R diagram or ERD,

is used as the basis for database implementation.

A database created without the benefit of a detailed blueprint is unlikely to be satisfactory.

Would you think it smart to build a house without the benefit of a blueprint?

So why would you want to create a database without a blueprint?

(Perhaps it would be OK to build a chicken coop without a blueprint,

but would you want your house to be built the same way?)


May 2, 2010


The playhead moves through the Timeline to indicate the current frame displayed on the Stage. The Timeline header shows the frame numbers of the animation. To display a frame on the Stage, you move the playhead to the frame in the Timeline.

B. Symbols: A symbol is a graphic, button, or movie clip that you create in Flash. Symbols automatically become part of the library for the current document. You create the symbol only once; you can then reuse it throughout your document or in other documents. There are three types of symbols: Buttons, Graphics, and Movieclips

C. Tweening: Tweened animation is an effective way to create movement and changes over time while minimizing file size. In tweened animation, Flash stores only the values for keyframes. Flash can create two types of tweened animation, motion tweening and shape tweening.

D. Actionscript: Macromedia Flash’s programming language. Based on Javascript.

E. Frame rate: The frames-per-second rate (FPS) that the animation plays. Flash’s default frame rate is 12 FPS. A rate that’s too slow will look choppy; a rate that’s too fast blurs the details.

F. Library panel: The Library panel is where you store and organize symbols created in Flash, as well as imported files, including bitmap graphics, sound files, and video clips.

G.Masking:– Masking is revealing portion of your picture or graphic in the layer below.

While surfing through net you might have come across lots of beautiful Flash effects such as ripple effect , some wording with sky background or glitter bordering an object, and wondered “How? What is the logic behind this”. The answer for all this is masking.

H. sensitive Property Inspector

Depending on what is currently selected, the Property inspector displays information and settings for the current document, text, symbol, shape, bitmap, video, group, frame, or tool. When two or more different types of objects are selected, the Property inspector displays the total number of objects selected

I.Bandwidth profiler. The Bandwidth Profiler is a tool that allows you to view reports of how your Flash file would load over a network connection of a certain speed. In order to use this, use Flash to open an SWF file (not the FLA file used to create it), and then click Control->Debug to either select a connection speed or create a custom profile for a connection speed.

J.Frame Label:- When the viewer presses the Submit button, you want Flash to jump to either the error message or the confirmation message, depending on what is entered in the text field. Labeling a frame helps you reference it in ActionScript easily. This is helpful for sending the playhead to a specific frame.

Write a function that responds to a click anywhere on the page by displaying an alert dialog. Display the event name if the user held Shift during the mouse click. Display the element name that triggered the event if the user held Ctrl during the mouse click. (Answer in Java Language)

May 2, 2010



<title>Mouse Events Example</title>

<script type=”text/javascript”>

function handleEvent(oEvent) {

var oTextbox = document.getElementById(“txt1”);

oTextbox.value += “\n    button down is ” +


var arrKeys = [];

if (oEvent.ctrlKey) {



oTextbox.value += “\n    keys down are ” + arrKeys;





<P>Use your mouse to click and double click the red square.</p>

<div style=”width: 100px; height: 100px; background-color: red”



<P><textarea id=”txt1″ rows=”15″ cols=”50″></textarea></p>



replace command for visual foxpro

May 2, 2010


what is website

May 2, 2010

A Web site is a related collection of World Wide Web (WWW) files that includes a beginning file called a home page. A company or an individual tells you how to get to their Web site by giving you the address of their home page. From the home page, you can get to all the other pages on their site. For example, the Web site for IBM has the home page address of (The home page address actually includes a specific file name like index.html but, as in IBM’s case, when a standard default name is set up, users don’t have to enter the file name.) IBM’s home page address leads to thousands of pages. (But a Web site can also be just a few pages.)

Since site implies a geographic place, a Web site can be confused with a Web server. A server is a computer that holds the files for one or more sites. A very large Web site may be spread over a number of servers in different geographic locations. IBM is a good example; its Web site consists of thousands of files spread out over many servers in world-wide locations. But a more typical example is probably the site you are looking at, We reside on a commercial space provider’s server with a number of other sites that have nothing to do with Internet glossaries.

A synonym and less frequently used term for Web site is “Web presence.” That term seems to better express the idea that a site is not tied to specific geographic location, but is “somewhere in cyberspace.” However, “Web site” seems to be used much more frequently.

You can have multiple Web sites that cross-link to files on each others’ sites or even share the same files.

Explain the JDB in depth & command line

May 2, 2010

jdb helps you find and fix bugs in Java language programs.



The Java Debugger, jdb, is a simple command-line debugger for Java classes. It is a demonstration of the Java Platform Debugger Architecture that provides inspection and debugging of a local or remote Java Virtual Machine.

Starting a jdb Session

There are many ways to start a jdb session. The most frequently used way is to have jdb launch a new Java Virtual Machine (VM) with the main class of the application to be debugged. This is done by substituting the command jdb for java in the command line. For example, if your application’s main class is MyClass, you use the following command to debug it under JDB:

% jdb MyClass

When started this way, jdb invokes a second Java VM with any specified parameters, loads the specified class, and stops the VM before executing that class’s first instruction.

Another way to use jdb is by attaching it to a Java VM that is already running. A VM that is to be debugged with jdb must be started with the following options:

Option purpose
-Xdebug Enables debugging support in the VM
-Xrunjdwp:transport=dt_socket,server=y,suspend=n Loads in-process debugging libraries and specifies the kind of connection to be made.

For example, the following command will run the MyClass application, and allow jdb to connect to it at a later time.

% java -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=n MyClass

You can then attach jdb to the VM with the following commmand:

% jdb -attach 8000

Note that “MyClass” is not specified in the jdb command line in this case because jdb is connecting to an existing VM instead of launching a new one.

There are many other ways to connect the debugger to a VM, and all of them are supported by jdb. The Java Platform Debugger Architecture has additional documentation on these connection options.

Basic jdb Commands

The following is a list of the basic jdb commands. The Java debugger supports other commands which you can list using jdb’s help command.

help, or ?

The most important jdb command, help displays the list of recognized commands with a brief description.


After starting jdb, and setting any necessary breakpoints, you can use this command to start the execution the debugged application. This command is available only when jdb launches the debugged application (as opposed to attaching to an existing VM).


Continues execution of the debugged application after a breakpoint, exception, or step.


Displays Java objects and primitive values. For variables or fields of primitive types, the actual value is printed. For objects, a short description is printed. See thedump command below for getting more information about an object.

NOTE: To display local variables, the containing class must have been compiled with the javac -g option.

print supports many simple Java expressions including those with method invocations, for example:

  • print MyClass.myStaticField
  • print myObj.myInstanceField
  • print i + j + k (i, j, k are primities and either fields or local variables)
  • print myObj.myMethod() (if myMethod returns a non-null)
  • print new java.lang.String(“Hello”).length()


For primitive values, this command is identical to print. For objects, it prints the current value of each field defined in the object. Static and instance fields are included.

The dump command supports the same set of expressions as the print command.


List the threads that are currently running. For each thread, its name and current status are printed, as well as an index that can be used for other commands, for example:

4. (java.lang.Thread)0x1 main      running

In this example, the thread index is 4, the thread is an instance of java.lang.Thread, the thread name is “main”, and it is currently running,


Select a thread to be the current thread. Many jdb commands are based on the setting of the current thread. The thread is specified with the thread index described in the threads command above.


where with no arguments dumps the stack of the current thread. where all dumps the stack of all threads in the current thread group. where threadindexdumps the stack of the specified thread.

If the current thread is suspended (either through an event such as a breakpoint or through the suspend command), local variables and fields can be displayed with the print and dump commands. The up and down commands select which stack frame is current.


Breakpoints can be set in jdb at line numbers or at the first instruction of a method, for example:

  • stop at MyClass:22 (sets a breakpoint at the first instruction for line 22 of the source file containing MyClass)
  • stop in java.lang.String.length (sets a breakpoint at the beginnig of the method java.lang.String.length)
  • stop in MyClass.<init> (<init> identifies the MyClass constructor)
  • stop in MyClass.<clinit> (<clinit> identifies the static initialization code for MyClass)

If a method is overloaded, you must also specify its argument types so that the proper method can be selected for a breakpoint. For example, “MyClass.myMethod(int,java.lang.String)”, or “MyClass.myMethod()”.

The clear command removes breakpoints using a syntax as in “clear MyClass:45”. Using the clear or command with no argument displays a list of all breakpoints currently set. The cont command continues execution.


The step commands advances execution to the next line whether it is in the current stack frame or a called method. The next command advances execution to the next line in the current stack frame.


When an exception occurs for which there isn’t a catch statement anywhere in the throwing thread’s call stack, the VM normally prints an exception trace and exits. When running under jdb, however, control returns to jdb at the offending throw. You can then use jdb to diagnose the cause of the exception.

Use the catch command to cause the debugged application to stop at other thrown exceptions, for example: “catch” or “catch mypackage.BigTroubleException. Any exception which is an instance of the specifield class (or of a subclass) will stop the application at the point where it is thrown.

The ignore command negates the effect of a previous catch command.

NOTE: The ignore command does not cause the debugged VM to ignore specific exceptions, only the debugger.

Command Line Options

When you use jdb in place of the Java application launcher on the command line, jdb accepts many of the same options as the java command, including -D, -classpath, and -X<option>.

The following additional options are accepted by jdb:

-sourcepath <dir1:dir2:…>

Uses the given path in searching for source files in the specified path. If this option is not specified, the default path of “.” is used.

-attach <address>

Attaches the debugger to previously running VM using the default connection mechanism.


Launches the debugged application immediately upon startup of jdb. This option removes the need for using the run command. The debuged application is launched and then stopped just before the initial application class is loaded. At that point you can set any necessary breakpoints and use the cont to continue execution.


Pass option to the Java virtual machine, where option is one of the options described on the reference page for the java application launcher. For example, -J-Xms48m sets the startup memory to 48 megabytes.

Other options are supported for alternate mechanisms for connecting the debugger and the VM it is to debug. The Java Platform Debugger Architecture has additionaldocumentation on these connection alternatives.

When Objects Are Created and Destroyed

May 2, 2010

An object is typically created using an allocation expression. The newInstance() methods of the Class or java.lang.reflect.Contructor class can also be used to create an instance of a class. In either case, the storage needed for the object is allocated by the system.

When a class is instantiated, a special kind of method called a constructor is invoked. A constructor for a class does not have its own name; instead it has the same name as the class of which it is a part. Constructors can have parameters, just like regular methods, and they can be overloaded, so a class can have multiple constructors. A constructor does not have a return type. The main purpose of a constructor is to do any initialization that is necessary for an object and java does not provide any way to explicitly destroy an object. Instead, an object is automatically destroyed when the garbage collector detects that it is safe to do so. The idea behind garbage collection is that if it is possible to prove that a piece of storage will never be accessed again, that piece of storage can be freed for reuse. This is a more reliable way of managing storage than having a program explicitly deallocate its own storage. Explicit memory allocation and deallocation is the single largest source of programming errors in C/C++. Java eliminates this source of errors by handling the deallocation of memory for you.

Java’s garbage collector runs continuously in a low priority thread. You can cause the garbage collector to take a single pass through allocated storage by calling System.gc().

Garbage collection will never free storage before it is safe to do so. However, garbage collection usually does not free storage as soon as it would be freed using explicit deallocation. The logic of a program can sometimes help the garbage collector recognize that it is safe to free some storage sooner rather than later. Consider the following code:

class G {

byte[] buf;

String readIt(FileInputStream f) throws IOException {

buf = new byte[20000];

int length =;

return new String(buf, 0, 0, length);



The first time readIt() is called, it allocates an array that is referenced by the instance variable buf. The variable buf continues to refer to the array until the next time that readIt() is called, when buf is set to a new array. Since there is no longer any reference to the old array, the garbage collector will free the storage on its next pass. This situation is less than optimal. It would be better if the garbage collector could recognize that the array is no longer needed once a call to readIt() returns. Defining the variable buf as a local variable in readIt() solves this problem:

class G {

String readIt(FileInputStream f) throws IOException {

byte[] buf;

buf = new byte[20000];

int length =;

return new String(buf, 0, 0, length);



Now the reference to the array is in a local variable that disappears when readIt() returns. After readIt() returns, there is no longer any reference to the array, so the garbage collector will free the storage on its next pass.

Just as a constructor is called when an object is created, there is a special method that is called before an object is destroyed by the garbage collector. This method is called a finalizer ; it has the namefinalize(). A finalize() method is similar to a destructor in C++. The finalize() method for a class must be declared with no parameters, the void return type, and no modifiers. A finalizer can be used to clean up after a class, by doing such things as closing files and terminating network connections.

If an object has a finalize() method, it is normally called by the garbage collector before the object is destroyed. A program can also explicitly call an object’s finalize() method, but in this case, the garbage collector does not call the method during the object destruction process. If the garbage collector does call an object’s finalize() method, the garbage collector does not immediately destroy the object because the finalize() method might do something that causes a variable to refer to the object again.[2] Thus the garbage collector waits to destroy the object until it can again prove it is safe to do so. The next time the garbage collector decides it is safe to destroy the object, it does so without calling the finalizer again. In any case, a finalize() method is never called more than once for a particular object.

[2] A finalize() method should not normally do something that results in a reference to the object being destroyed, but Java does not do anything to prevent this situation from happening.

The garbage collector guarantees that the thread it uses to call a finalize() method will not be holding any programmer-visible synchronization locks when the method is called. This means that afinalize() method never has to wait for the garbage collector to release a lock. If the garbage collector calls a finalize() method and the finalize() method throws any kind of exception, the garbage collector catches and ignores the exception.

Working with templates

May 2, 2010

Templates are prototypes for different types of documents. Templates are sort of like blank forms. They don’t necessarily contain text, though. A template might contain only a collection of the particular fonts and format styles for a particular type of document, or it might contain all the text of, say, your boilerplate contract.

Whenever you create a document, WordPerfect uses a template. The blank document that you see when you start WordPerfect is based on a standard template called wp12us.wpt. If you create a document by clicking the New Blank Document button on the toolbar (the one that looks like a blank page with the corner turned down) or by pressing Ctrl+N, WordPerfect again uses that standard template. If you start a new document by choosing File, New from Project, however, WordPerfect explicitly asks you what kind of template to use.

Using templates

There’s not much in the standard template — at least, not much as it comes out of the box from WordPerfect (you can change it, though). Mostly, the standard template contains the initial paragraph, character, and page formatting that WordPerfect uses for your documents. If you have to change your fonts and other formatting every time you create a new document, you probably should edit the standard template.

Here’s how to use a template other than the standard one:

1. Choose File, New from Project.

The PerfectExpert dialog box appears. WordPerfect has so many templates that they’re divided into categories.

2. In the pull-down list at the top of the dialog box, click a template category.

You should probably stick with WordPerfect’s standard list. So if WordPerfect doesn’t show up in this box, click the down arrow and scroll up and down the list until you find it. It’s usually close to the top.

3. In the list of templates just below the pull-down list, click the template that you want to use.

Each template has a brief description at the bottom of the dialog box.

4. Click the Create button.

Some templates kick off a PerfectExpert to guide you through creating a document. If nothing appears to happen when you click Create, that’s probably what’s going on. Arousing and invoking Experts takes some time.

Some of the templates contain PerfectScript macros to provide an added level of customization. Because macros can sometimes be used to spread viruses, WordPerfect warns you before you create the new document. In fact, based on dire warnings in the message box, you may think it’s crazy not to disable the macros before continuing. However, if you know that the template came from WordPerfect and is not something you or someone added, you should feel comfortable clicking the No button (to not disable the macros). If you decide to disable the macros, automated tasks that the template would normally do probably won’t operate correctly.

Creating a normal template

In addition to using prebuilt templates, you can create your own. Perhaps they won’t be as fancy as the WordPerfect ones, with dialog boxes and PerfectExperts and stuff, but they can end up pretty fancy and customized for your needs.

To create a regular template, follow these steps:

1. Choose File, New from Project.

2. Click the Options button in the PerfectExpert dialog box.

3. Choose the Create WP Template item in the list.

A template is created that will look just like a document. If you have a prototype document that you’ve already created, you can include it in your document by choosing Insert, File.

4. Customize the template.

Consider the following ways to set up your template:

• Add or modify styles in the template, so that any documents you create from the template have those same style settings.

• Set up headers or footers, margins, or any custom page layout setting.

• Add boilerplate text or graphics, such as a letterhead or a signature line, that will appear in each document you create based on the template.

5. Choose File, Save.

6. Type a description and name for your template and select a category.

The Template name is the name your template will have on disk. The Template category is where your template will live in the PerfectExpert dialog box’s template groupings; those are the names in the drop-down list at the top of the PerfectExpert dialog box.

7. Click OK to save the template.

Editing templates works the same way: Select the template, but instead of clicking Create WP Template in the PerfectExpert dialog box (Step 3), click Options and select Edit WP Template. Edit to your heart’s content. When you’re finished, choose File, Save.

Definition of to-do list

May 2, 2010

ToDoList is a rare form of task management tool, one that allows you to repeatedly sub-divide your tasks into more manageable pieces whilst still presenting a clean and intuitive user experience.

ToDoList has been in continuous development for the last 6 years and is an ongoing project.

Your tasklists are stored in XML which provides many opportunities for advanced formatting and printing using stylesheets.

ToDoList’s flexible design makes it ideal for both IT related projects as well as more general GTD uses.

We welcome feature requests and respond promptly to all reports of bugs or unexpected behaviour.

Latest ToDoList Release (6.0)

This is the latest formal (non-beta) release. To install ToDoList simply unzip this link into any folder and then double-click the resultant program icon.

Install Project Server 2007 in Windows Server 2008 (single-server installation)

May 2, 2010

This article discusses the requirements and steps for installing Microsoft Office Project Server 2007 in a stand-alone Windows Server 2008 environment. It covers a new installation of Project Server 2007 on the Windows Server 2008 operating system and does not cover upgrading from Windows Server 2003.

Overview of setting up Project Server 2007 on Windows Server 2008

Project Server 2007, Windows SharePoint Services 3.0, and Office SharePoint Server 2007 RTM versions are not supported on Windows Server 2008. Installing updated versions of Project Server 2007, Windows SharePoint Services 3.0, and Office SharePoint Server 2007 is required for installation on Windows Server 2008. Installing Project Server 2007 RTM without updates causes a program compatibility issue with Office SharePoint Server 2007.


Updated versions of Project Server 2007, Windows SharePoint Services 3.0, and Office SharePoint Server 2007 include Service Pack 1, Infrastructure Updates, Cumulative Updates, and Service Pack 2.

System requirements

Before installing Office Project Server 2007 on Windows Server 2008, verify that the computer meets the hardware and software requirements listed in this section.

Hardware requirements

Component        Minimum            Recommended


2.5 gigahertz (GHz)

Note:   An Intel Itanium 2 processor is required for Windows Server 2008 for Itanium-Based Systems

Dual processors that are each 3 GHz or faster


1 gigabyte (GB)

2 GB


NTFS file system–formatted partition with a minimum of 3 GB of free space

NTFS file system–formatted partition with 3 GB of free space plus adequate free space for your Web sites


DVD-ROM drive

DVD drive or the source copied to a local or network-accessible drive


1024 × 768

1024 × 768 or higher resolution monitor


56 kilobits per second (Kbps) connection between client computers and server

56 Kbps or faster connection between client computers and server

Software requirements

Office Project Server 2007 has the following software requirements. Because Office Project Server 2007 is built on Windows SharePoint Services 3.0, the requirements that apply to Windows SharePoint Services 3.0 also apply to Office Project Server 2007.

Operating system

We highly recommend that you apply all critical updates. You can use the following editions of Windows Server 2008:

The Windows Server 2008 Standard operating system

The Windows Server 2008 Enterprise operating system

The Windows Server 2008 Datacenter operating system

The Windows Web Server 2008 operating system

The Windows Server 2008 for Itanium-Based Systems operating system

The 64-bit edition of the Windows Server 2008 Standard operating system without Hyper-V

The 64-bit edition of the Windows Server 2008 Enterprise operating system without Hyper-V

The 64-bit edition of the Windows Server 2008 Datacenter operating system without Hyper-V

Web browser

Internet Explorer 7.0 with the most recent service packs.

Windows SharePoint Services 3.0 or Office SharePoint Server with recent updates

Windows Server 2008 requires an updated version of Office SharePoint Server 2007 and Windows SharePoint Services 3.0.

Application Server role

The Application Server role must be installed on the computer.

Internet Information Services 7.0

The Web Server (IIS) role must be installed on the computer with the Application Server Foundation and Web Server (IIS) Support role services.

Microsoft .NET Framework 3.0

Installing the Application Server role installs the Microsoft .NET Framework 3.0 by default on Windows Server 2008.

Add server roles

Navigate to the Server Manager in Windows Server 2008, and then click Roles.

Click Add Roles and select the Application Server and Web Server (IIS) roles.

When prompted in the Add Roles Wizard to Add features required for Application Server, click Add Required Features, and then click Next to continue in the Add Roles Wizard dialog box.

In the Add Roles Wizard – Select Role Services dialog box, select Web Server (IIS) Support, and verify that the Application Server Foundation box is selected.

Click Next to begin the installation process.

Install Project Server 2007 on Windows Server 2008

Navigate to the local setup directory and run setup.exe.

In the Enter Product Key page, type the 25-character product key, and then click continue.

On the Installation Types page, click Basic to start the installation.

On the page that appears when the installation is complete, select Run the SharePoint Products and Technologies Configuration Wizard now and then click Close. You must run the SharePoint Products and Technologies Wizard to automatically complete the required provisioning steps.

On the Welcome to SharePoint Products and Technologies page, click Next.

A confirmation dialog box appears stating that the following services must be restarted or reset during the configuration:

Internet Information Services

SharePoint Administration Service

SharePoint Timer Service

Click Yes to continue. A progress indicator appears.

When configuration is complete, the Configuration Successful page will appear. Click Finish.

The Manage Project Web Access page appears and will list the Project Web Access instance that is being provisioned. Click the Refresh Status button from time to time to check whether the Project Web Access instance has been provisioned. When it has been provisioned, click the URL to go to the Project Web Access home page.