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Database Programming
Databases are collections of tables that maintain and display information, often collaboratively; this information can be used for interaction with an application or gaining general knowledge. Questions about database engines and modifying or using them belong in this category.
8,803 Questions
Are there different types of skateboards?
Yes there are good brands of boards such as element, baker, birdhouse, active and DVS.
Is a system for reservation just like in hotels, restaurants, flight reservations to insure your needs.
What are the applications of waterfall process model?
1)whenever we are developing a small application we go for waterfall model.
2)when we have a short term project.
3)when we are sure that the requirement never changes.
These are the stages in which we adopt the waterfall model.
Write the algorithm to find the largest number of three number?
To determine the largest of any group of numbers, we must first determine the largest of any two numbers. For that we use the following simple algorithm:
If number A is greater than number B, then return number A otherwise return number B.
In C++ we can encode this algorithm using the following template function:
T& max( T& a, T& b) { return( a>b?a:b ); }
Using this one basic function we can build more complex functions to return the largest of any quantity of numbers. For instance, to return the largest of any three numbers, we would use the following:
T& max( T& a, T& b, T& c ) { return( max( max( a, b ), c )); }
To return the largest of any four numbers, we would use the following:
T& max( T& a, T& b, T& c, T& d) { return( max( max( a, b, c ), d )); }
We could continue in this fashion, but there is a much simpler approach: place all the values in a vector and return the maximum value of the vector. The following example demonstrates this with a vector containing 10 random values:
#include
#include
#include
template
T& max(T& a, T& b ) { return( a>b?a:b ); }
template
T max( std::vector
{
std::vector
int iResult = *it;
while( ++it != v.end() )
iResult = max( iResult, *it );
return( iResult );
}
int main()
{
srand(( unsigned ) time( NULL ));
std::vector
printf( "Array: " );
for( std::vector
{
*it = rand() % 100 + 1;
printf( "%d ", *it );
}
printf( "\n");
printf( "Largest: %d\n", max(v) );
return( 0 );
}
Can weak entity be converted into strong entity?
The primary key of a weak entity set is formed by taking the primary key of the strong entity set on which its existence depends (see Mapping Constraints) plus its discriminator.
A strong entity set has a primary key. All tuples in the set are distinguishable by that key. A weak entity set has no primary key unless attributes of the strong entity set on which it depends are included. Tuples (a particular row) in a weak entity set are partitioned according to their relationship with tuples in a strong entity set. Tuples within each partition are distinguishable by a discriminator, which is a set of attributes.
What is the difference between tree search and graph search?
A graph is a set of vertices which are connected to each other via a set of edges.
A tree is a special type of hierarchical graph in which each node may have exactly one "parent" node and any number of "child" nodes, where a parent node is one level closer to the root and a child node is one level further away from the root.
How many memory variables can be defined in Foxpro?
The same as in other programming languages. A place to store a value. A variable may be of different types, including logical, string, numeric, or date.
Here is an example that uses a variable:
x = 5
? "The square root of", x, " is ", sqrt(x).
In FoxPro, it isn't necessary to declare variables. It is safer, though, in order to avoid conflicts between different modules, to declare the variable (usually with the LOCAL keyword if you use Visual FoxPro, or PRIVATE if you use the old FoxPro 1.x or 2.x).
All variables are of a type which in some languages is called "variant", that is, the type can change at runtime.
There Are Two main types of data. Qualitative data are expressed As numbers, obtained by counting or measuring. Another type of data is called an inference.An inference is a logical interpretation based on prior knowledge or experience.
An individual object of a certain class. While a class is just the type definition, an actual usage of a class is called "instance". Each instance of a class can have different values for its instance variables
A case or occurance of something.
7 Why is binary code suitable for use with computers?
Binary is well suited for computers because it only needs two symbols to represent numbers a 1 and a 0. In a computer a circuit can be in 2 states on and off hence in the simplest implementation"on" represents a 1 and "off" a 0.
Draw the data flow diagram of hotel management?
Maybe it does not exist just for hotel management. However, you may want to take a look at the more widespread general DFD design tools such as the free Dia (http://live.gnome.org/Dia) or the commercial Visio (http://en.wikipedia.org/wiki/Microsoft_Visio).
Differences between b tree and b tree?
Answer:
Binary tree is a tree data structure in which each node has at most two children. Typically the first node is known as the parent and the child nodes are called left and right.
A B-tree is a tree data structure that keeps data sorted and allows searches, insertions, deletions, and sequential access in logarithmic amortized time. The B-tree is a generalization of a binary search tree in that more than two paths diverge from a single node. Unlike self-balancing binary search trees, the B-tree is optimized for systems that read and write large blocks of data. It is most commonly used in databases and filesystems.
How is java both a programming language and a platform?
By using Navite Interface we write this type of code
What is the first in first out data structure?
In computer programming, first-in first-out (short FIFO) describes a data structure which implements a chronological order, such that when multiple elements are added to the data structure, the normal retrieval method returns the elements in the order in which they were added.
FIFO structures are often used to implement queues and buffers. The alternative commonly used chronological sorting container is LIFO, short for last-in first-out.
What are the disadvantages of file systems?
1)Limited Security
2)limited Data Sharing
3)Data Redundancy
4)Integrity Problems
How can you use hacking in c program?
That entirely depends on what you want it to do, however it is easy to send commands to the command line using subprocess.Popen(), read files and modify them or back them up using the built in open(), or delete files.
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The difference between Real data type and integer data type?
An integer data type is any type of number without a fractional part.
Signed vs unsigned of any data type refers to whether or not that data type can store negative numbers (numbers with a negative sign). The typical way to store the sign information for a number is to reserve one bit of information to do so.
For a signed 32-bit integer (a common integer size), this means that there are 31 bits available to hold information about the value of the number and 1 bit reserved for signifying negatives. This means that the range of data for a 32-bit signed integer is [-2147483648, 2147483647].
If you use an unsigned 32-bit integer, you can use that extra bit to store more positive number values. The range of data for a 32-bit unsigned integer is [0, 4294967295].
in short law FOR n bits
signed rang[-2n-1 -------- 2n-1 -1]
unsigned rang [0----------2n-1]
The main purpose of documentation is to keep records. Documentation is an integral part of all sectors of business and technology has simplified it.
What is java primitive data types?
Any data that is not stored as an object - like the integral data types (int, long, etc.), or boolean variables.
Any data that is not stored as an object - like the integral data types (int, long, etc.), or boolean variables.
Any data that is not stored as an object - like the integral data types (int, long, etc.), or boolean variables.
Any data that is not stored as an object - like the integral data types (int, long, etc.), or boolean variables.
What are the disadvantages and advantages of prototyping over system development life cycle?
Basically speaking, there are five advantages that prtotyping could bring about.
1) Provides functionality and interactions. Static high-fidelity mockup and wireframe are unable to convey animation. But a prototyping with interaction can do it pretty well.
2) Make actual communication with your boss, stockholders and users. The communication is necessary, the more they understand your design, the bigger the chance you can buy them in.
3) Detect errors earlier and save time and money. Trust me, any mistakes cost you less in prototyping stage than to be found in the later development stage.
4) Enhance collaboration within your team members internal. It can improve efficiency largely.
5) Involve user feedback and help to do multiple-test. It’s a key factor to iterate and update.
So, it's necessary to make prototypes before you develop actual products or websites. When it comes to prototyping, I would like to share one tool with you: Mockplus Cloud.
Mockplus Cloud - Connect your entire product design workflow.
As a brand-new collaboration tool for designers and developers, it goes far beyond design and workflow—allowing mobile designers to create masterpieces. It allows you to upload your wireframes and visual designs from Photoshop, AdobeXD, and Sketch, and add them to your project folder.
A full set of features about prototyping, commenting, collaborating and design handoff enable you to create a product from the start to finish.
Hopefully, this helps.
It is up to the designer of the compiler to decide...
it can be something like this:
struct Type;
struct Block;
typedef struct Variable {
const char *name;
struct Type *type;
struct Block *block; /* refers to the block that is the scope of the variable */
int attributes; /* volatile, const, static etc */
} Variable;
Write a program in c to implement the depth first traversal?
#include <iostream.h>
#include <conio.h>
class graph
{
private:int n;
int **a;
int *reach;
int *pos;
public:graph(int k=10);
void create();
void dfs();
void dfs(int v,int label);
int begin(int v);
int nextvert(int v);
};
void graph::graph(int k)
{
n=k;
a=new int *[n+1];
reach=new int[n+1];
pos=new int [n+1];
for(int i=1;i<=n;i++)
pos[i]=0;
for(int j=1;j<=n;j++)
a[j]=new int[n+1];
}
void graph::create()
{
for(int i=1;i<=n;i++)
{
cout<<"Enter the "<<i<<"th row of matrix a:
";
for(int j=1;j<=n;j++)
cin>>a[i][j];
}
for(int k=1;k<=n;k++)
reach[k]=0;
}
void graph::dfs()
{
int label=0;
for(int i=1;i<=n;i++)
if(!reach[i])
{
label++;
dfs(i,label);
}
cout<<"
The contents of the reach array is:
;
for(int j=1;j<=n;j++)
cout<<reach[j]<<" ";
}
void graph::dfs(int v,int label)
{
cout<<v<<" ";
reach[v]=label;
int u=begin(v);
while(u)
{
if(!reach[u])
dfs(u,label);
u=nextvert(v);
}
}
int graph::begin(int v)
{
if((v<1)&&(v>n))
cout<<"Bad input
";
else
for(int i=1;i<=n;i++)
if(a[v][i]==1)
{
pos[v]=i;
return i;
}
return 0;
}
int graph::nextvert(int v)
{
if((v<1)&&(v>n))
cout<<"Bad input
";
else
for(int i=pos[v]+1;i<=n;i++)
if(a[v][i]==1)
{
pos[v]=i;
return i;
}
return 0;
}
void main()
{
clrscr();
int x;
cout<<"Enter the no of vertices:
";
cin>>x;
graph g(x);
g.create();
cout<<"dfs is.....";
g.dfs();
getch();
}
What are the drawbacks of current commercial databases?
With a DBMS, you lose the intrinsic control of data management that exists in an integrated software solution. For instance, if you were to write a program in C++, you have the option to directly control how your program's data is handled by the actual memory on the host computer, how that memory is addressed and allocated and cached stored on the disk, even on a bit by bit level if you so choose.
On the programming layer, you also have direct control over how
different tasks will operate on your data as well. So instead of creating related tables in a relational system and using SQL to manipulate that data you can create routines that will directly manipulate the data to your exact specifications.
So, instead of building tables you may store you data in a linked list or binary tree, which if you're good, could show very, very significant improvements for tasks such as searching and sorting. A DBMS does mostly the same task, however they've devised a very general way of organizing data that works generally for all problems. If you build a custom data solution instead of taking direct routes you can find ways to optimize your code in a way that cuts through the structure and performs tasks just not possible on a DBMS.
However, considering the amount of work that goes into creating an integrated data solution and the strong likelihood that information theory experts/gods who actually work for database companies like Oracle are way, way better programmers then you, there is probably no significant advantage to not using a DBMS unless the ammount of data you are handleing is very small.
PS: I recommend postgresql. People will try to tell you how great mysql is, but its because they're weak. PGSQL is the best DB you can get for nothing in the world. Good luck.
What are the advantage of database?
In every field of work there is a need of maintaining database to store records . The major advantages of the DBMS are the speed , flexibility, ease , and that it can be stored anywhere. Also the data is very consistent and integrated.
Is it possible to have a completely graphical programming language?
Almost any computer language can do GUI manipulations if provided by a GUI library. Some can be add-ons because the language itself does not have a direct method of doing GUI drawing, etc.
Languages such as C and C++ for example do not have a native GUI interface because they are not tied directly to a machine architecture or to an operating systems platform. However, that is not to say that they cannot do GUI manipulations; it just isn't built into the language, but there are 3rd party add-ons that do the manipulations for you.
Other languages, such as C# and Java, have built-in gUI libraries that work the same way regardless of the Operating System they are on. In that way they support GUI operators natively, without the use of an add-on GUI library.
