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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

What is valid data?

Before your program makes use of any data gathered from outside the program, whether by user input, file input, or reading from a database, you should validate that information - you need to check to make sure it is the correct type and format of data before you feed it in to your program.

If your program expected a number but was given a string, bad things would likely happen.

People who disregard validation leave themselves open to errors, crashes, and buffer overflows.

What are the different between stack and queue?

  • A stack is generally First In, Last Out, and a queue is First In First Out.
  • Item can be added or removed only at one end in stack and in a queue insertion at the rear and deletion from the front.
  • The basic operation of stack are 'push' and 'pop', on other hand of queue are 'enque' and 'dequeue'.

What is the Establishment in the nation?

the Establishment Clause prohibits the government from creating an official or established church, preferring one religion over another, or benefiting believers instead of nonbelievers

Do you have a table without columns?

You cannot have a table without columns. Columns are what make up the structure of a table. It would be like a house without walls.

Write a short note on table creation?

table is created to store the information in rows and coloums

in table creation it consist of two types

cell spacing

cellpadsing

cell spacing is define as the distance between two cell

cell pading is define as the distance between cell and the wall

the creation of table <tr>

the creation of table heading is <th>

to create a row <td>

an example program

<table>

<tr>

<th>heading 1</th>

<th>heading 2</th>

</tr>

<td>data 1</td>

<td>data 2</td>

</tr>

<tr>

<td>data 3</td>

<td>data 4</td>

</tr>

</table>

How you write x to the power 2?

write the character x, the place a small numeral two on the upper right corner of x.

if needed to write on ms word then holding ALT key press 2 5 3(no space in between) on your keyboard. ALT +253

Ho big is a megabyte?

1 megabyte equals

8,388,608 bits

1,048,576 bytes

1,024 kilobytes

1 megabyte

0.0009765625 gigabytes

0.0000009536 terabytes

0.0000000009 petabytes

What term refers to a collection of related records?

Database system is collection of data .Also Database system refers to a collection of related records.

What can you use to duplicate a file or program?

Right-click the file/program, click "Copy", right-click where you want the duplicated file/program to go, and click "Paste". ------ Or to duplicate a program you can use Installrite http://www.epsilonsquared.com/

Which is not a feature of access reports?

Runs natively on any Macintosh computer made in the last 20 years, is easy to program by ordinary people who do know what they want and how to get it done, is the most popular database program for the customers / users point of view.

Pick one of the above!!!!!!!!!!!!!!!!!!!!!!!!!

A full node is a node with two children Prove that the number of full nodes plus one is equal to the number of leaves in a binary tree?

Let N = the number of nodes, F = number of full nodes, L = the

number of leaves, and H = the number of nodes with one child (or half nodes).

The total number of nodes in a binary tree equals N = F + H + L.

Because each full node is incident on two outgoing edges, each half node is

incident on one outgoing edge, and each leaf is incident on no outgoing edge it

follows that the total number of edges in a binary tree equals 2F + H. It is also

true that the total number of edges in a tree equals N 1. Thus,

2F + H = N 1

H = N 1 2F

Subbing this value of H into N = F + H + L gives,

N = F + N 1 2F + L

N N + 1 = F + L

F + 1 = L

How many unique values can you assign in a 3 byte alphanumeric field?

There are 26 alphabetic characters (a-z) and 10 numeric (0-9) which together form 36 alphanumeric characters. If you include capital letters, then you have 62 (36 + 26) alphanumeric characters.

62 * 62 * 62 = 238,328

How many mahasagar?

1. Hind mahasagar

2. Prashant mahagar

3 atlantica

4.arcktica

5.antarktica

What are attributes and entities in database system management?

Entities are the things you're keeping track of. In an video rental database, you keep track of customers, invoices, titles, copies, etc. These are represented in tables where the rows are individual instances of a customer or title. The columns are the attributes, the things that tell us about the instance in the row. The customer's name, address, city, balance, etc. are attributes that help identify the customer. An invoice's attributes might be price, number, date, paid/unpaid, etc. Databases link entities/tables so that a customer, described by his attributes, can be associated with his invoices, describe by his attributes and selected by the invoices 'unpaid' column. "Here's your bills for the last month, Mr. Smith."

Explain the difference between a weak and a strong entity set?

An entity set that does not possess sufficient attributes to form a primary key is called a weak entity set. One that does have a primary key is called a strong entity set.

The discriminator (or partial key) of a weak entity set is the set of attributes that distinguishes among all the entities of a weak entity set

The existence of a weak entity set depends on the existence of a identifying entity set. It must relate to the identifying entity set via a total, one-to-many relationship set from the identifying to the weak entity set

We depict a weak entity set by double rectangles in E-R diagram. We underline the discriminator of a weak entity set with a dashed line in E-R diagram.

How can the base class data be accessed from database directly using derived class?

In order to access a base class member the base class member must be declared protected or public. Private data is only accessible to members of the same class and to friends of the class. I'm not entirely sure what you mean by accessing from a database. A derived class does not require a database in order to access its base class members, it only requires protected access at the very least. Note that although you can declare derived classes to be friends of their base classes and thus allow private access, it would be an unusual design since base classes should never know anything about any of their derivatives.

Is there a central database for medical records?

With regard to hospital institutions, at this point in time, there is not a central data

base for medical records; however, by 2014 institutions (hospitals and private physician

practices) are being strongly encouraged to attain an electronic health (medical) record. By

acquiring an electronic health record, this will aide in the facilitation of acquiring a central

data base in the not too distant future.

How do you validate and retrieve data from database?

How do you validate and retrieve data from database?" How do you validate and retrieve data from database?"