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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
The correct spelling is database software instead of database softwear. Database software is a utility or software program. It is used to make databases and manage and edit the information that is kept in them.
Were was World War 1 triggered?
World War I had many causes, but the primary cause was the assasination of Archduke Franz Ferdinand of Austria while in Sarejevo on June 28, 1914.
In the context of computer programming and database management, an SQL client is a software application or tool that allows users to connect to a database server and execute SQL queries against the database.
The SQL client provides an interface for users to enter SQL commands, execute those commands against the database, and view the results. Some examples of SQL clients include MySQL Workbench, Microsoft SQL Server Management Studio, and Oracle SQL Developer.
SQL clients are commonly used by database administrators, software developers, data analysts, and other professionals who work with databases. They are essential tools for managing and manipulating data in relational databases.
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What does primary key mean in database form?
In a Database, more specifically a relational model, columns of one table that relate to columns of another table are called "key columns".
There are two types of "key" columns. Foreign key and Primary Key.
The Primary key of a table is usually a column within a table that contains unique data which cannot be duplicated. Think of it as a "unique identifier" column. You can actually create an array of key columns in a table to represent a unique series of values as well. (so PKey 1,2,3 are unique and no group of PKey's 1,2,3 will be the same, even though sometimes any one of those columns may contain a single value that has been duplicated, the consolidated value of all 3 will never be replicated).
The Primary key of table A is linked to the Primary key of Table B for instance. Table B's Primary Key in this relationship is then called a "Foreign Key", meaning "The Primary Key of the OTHER table".
That's a pretty basic understanding of how they work. There is a little bit more involved but this is the gist of it.
What are class diagrams in UML?
Class diagram is UML diagram describing static structure of a system on the (lowest) level of classifiers (classes, interfaces, etc.). It shows system's classifiers, their attributes, and the relationships between classifiers.
The following nodes and edges are typically drawn in a UML Class diagram:
- Class
- Interface
- Interface Realization
- Required Interface
- Association
- Generalization
- Dependency
Difference between an entity class and an entity instance?
"An entity is a person, place, event, or thing about which data is collected...An instance is an occurence of an entity." - Systems Analysis & Design (4th) - Dennis
An example of this would be STUDENT as the entity while JACK SMITH is an instance of that entity.
If an entity is an individual "person, place, event, or thing about which data is collected", then an entity is an instance. Linguistically, entity is just another word for a single thing ("The existence of a thing as contrasted with its attributes.", Merriam-Webster's On-line Dictionary). Entities that have the same attributes are grouped in what are best called entity classes (it doesn't make sense to refer to a collection of entities as an entity). Entity and entity class are data modeling terms. The corresponding object modeling terms are object and class, albeit that a class typically has operations, which are foreign to an entity class.
What are the properties of relations in database management?
1.each row must have unique(pk)in a relation.
2.database must have a unique name.
3.each column must have unique name.
What is High-level nature of hierarchical network and relational database management system?
A Relational Database Management System (RDBMS) is a Database Management System (DBMS) that is based on the relational model as introduced by E. F. Codd. Most popular commercial and open source databases currently in use are based on the relational model.A short definition of an RDBMS may be a DBMS in which data is stored in the form of tables and the relationship among the data is also stored in the form of tables.
Network topology is the physical interconnections of the elements (links, nodes, etc.) of a computer network. A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more other nodes in the network and the mapping of these links and nodes in a graph results in a geometrical shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flows between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
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What does sorry having problems with database mean?
It means that there is an issue with a data base which has information in it, so they can not help you at the moment.
redundancy means back up
so a built in redundancy in a computer is like a 2nd C: drive in case the first fails it can be switched instantly, also a 2nd power supply to minimize downtime.
in a factory this could mean having 2 sets of control boards inside a machine so if one breaks down the other can be used while the broken one is repaired or replaced.
What is the c programmind code for simpsons one third rule to evaluate integrals?
#include<stdio.h>
#include<conio.h>
#include<math.h>
#define f(x) (sin(x*x))
void main()
{
float a,b,h,x,s,n,aaa,h1,h2,p=0.0,p1=0.0,pp,sum,k,i=0.0;
int j=1,co;
clrscr();
printf("\n Plese Enter lower limit :");
scanf("%f",&a);
printf("\n Plese Enter upper limit :");
scanf("%f",&b);
printf("\n Plese Enter the number of Intervales::");
scanf("%f",&n);
h=(b-a)/n; //Calculiting the value of h
printf("The ..................=%f",h);
x=a+h;
s=f(a)+f(b); //Calculiting the First term & last term
while(j<n)
{
if((j%2)==0) //checking even and odd terms
i=i+(2*f(x)); //Calculiting the even terms
else
i=i+(4*f(x)); //Calculiting the odd terms
x=x+h;
j++;
}
i=(h/3)*(i+s); //putting all data in to the formula
printf("\nThe value of the integral is %f",i);
// part is for Error calculation
h1=b-h; h2=a+h;
pp=(7*(f(h2)+f(h1)));
sum=a-h;
k=b+h;
x=a+(2*h);
for(co=2;co<n-2;co++)
{
if(co%2==0)
p=p+(f(x));
else
p1=p1+(f(x));
x=x+h;
}
aaa=(-(h/90))*( ( f(sum)+f(k) )-4*(s) +7*( f(h1) )-(8*p)+(8*p1) );
printf("\nThe Error is= %f",aaa);
getch();
}
How do you manipulate a data in a database?
You can manipulate data in a database by using the DML - Data Manipulation Language statements. These include:
- Insert
- Update and
- Delete
By using these 3 statements you can manipulate the data in a database.
List the importance of security and data verification?
- To make sure the source data are well defined, documented.
- To ensure data accuracy.
- To ensure data completeness.
- To ensure data consistency.
- To ensure the reliability of the data collected.
What are the advantages and disadvantages of binary trees?
1. This makes the Tree more complex.
as we need to keep the record of node's Predecessor and successor
2. Postorder traversal is too complex and there might be changes of errors when
both the child are not present & both values of nodes pointer to their
Predecessor.
-Snehal Javheri
What does a sort mean in a database?
Sort refers to the action wherein the data fetched from a database table is ordered as per a specific criteria. The default order of sort is Ascending and the user can do a descending sort by using the keyword DESC after the order by keyword.
Ex: select * from employee_details order by employee_num desc
If the above statement is executed data will be displayed in descending order of employee numbers.
What are the measures to secure and maintain data integrity?
these are some measures to secure and main5ain data integrity Software Restrictions: passwords, encryption, virus protection,
firewall; physical access restrictions: biometric systems, guards,
locks; fire/water proof cabinets; archiving; backup and recovery
procedures; propriety data and software.
this cam from the cxc sullybus for 2011
Distinct features of queue and stack?
A stack is a data structure in which last item inserted is taken out first . That's why they are known as LIFO (last in first out). Inserting an item in stack is termed as push and taking an item out from stack I s termed as pop. Some applications of stack are : Polish notation, reversing string, backtracking , quick sort algorithm etc. The queue is a linear data structure where operations od insertion and deletion are performed at separate ends also known as front and rear. Queue is a FIFO structure that is first in first out. Whenever a new item is added to queue, rear pointer is used. and the front pointer is used when an item is deleted from the queue.
What are the duties of database administrator?
A database administrator is a person who works in IT and who has a bachelor's degree in computer science, information technology or engineering. The duties involve designing and developing databases, improving performance of databases and system monitoring.
Because it uniquely identifies each record in that table, No two records can have the exact same entry in the field designated as the primary key.
