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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 the difference between Database and databank?
Databank (usually a device) containing several databases.
What advantages of QBE compared to SQL?
QBE is an advantage over SQL as it is a visual technique allowing non-experts to do searches, as it is simple to understand.
What is another name for a file allocation unit?
another name for a file allocation unit is a cluster.
What is the ATM Block diagram?
in ATM Block diagram there is user who can insert his card then enter pin no. request goes to bank get approval then insert amount then get result
attributes for entity ATM
1.user ID
2. password(pin no.)
3. amount
What might a bank use a database for?
To store detail of customers,
how much they have in the bank,
what their billing address is,
the account name,
account type,
sort code,
account number,
and more like them above.
Disadvantages of computerized payroll system?
The primary disadvantage of a computerized payroll system is human error. A computer is only as good as the person inputting the information.
What is the purpose of the payroll system?
The payroll program is run at a specific point in time, not only to calculate an employee's basic remuneration but also any special payments, overtime payments or bonuses that must be effected for the period in question
What is the theoretical fastest transfer rate for a 10mbps connection in kB?
10 MegaBits Per Second * 1000 would equal 10,000 KiloBits Per Second or 10,000,000 Bits Per Second
Why must the primary key of a parent table be determined before the foreign key in the child table?
Because the foreign key is copied from the primary key of the parent table
What difference between data warehouse and traditional database used OLTP?
{| |+ Differences |- | Data warehouse database OLTP database Designed for analysis of business measures by categories and attributes Designed for real time business operations. Optimized for bulk loads and large, complex, unpredictable queries that access many rows per table. Optimized for a common set of transactions, usually adding or retrieving a single row at a time per table. Loaded with consistent, valid data; requires no real time validation Optimized for validation of incoming data during transactions; uses validation data tables. Supports few concurrent users relative to OLTP Supports thousands of concurrent users. |}
http://www.geekinterview.com/question_details/15800
CheckPoint Chapter 2 Programming Problem?
System-Level Requirements Example
Consider the Paint the Room program, in which you developed what are often called system-level requirements-the basis for all subsequent analysis and design steps. The following steps will take these system-level requirements and refine them into a detailed blueprint for the program.
Up to this point, you have identified the processes the program must perform, but you have not given any consideration to exactly how the processes work together to solve the problem. At this point, you must generate a description of the processing using pseudocode, a natural language description of the processing the application must perform.
The natural place to start is the system-level requirements you identified in the Input-Process-Output (IPO) chart. Determine how the processes work together: Once you have determined the top-level logic, you can then design each of the individual processes. It is this step-wise refinement process that allows you to conceptualize a vague problem into increasing levels of details in order to actually generate a working program. This point is important because the step-wise refinement pattern is used throughout the entire program development-each new piece of information is based on, and is a refinement of, the information uncovered in the previous step.
For this week's CheckPoint, you will refine the IPO table into a complete design, as demonstrated on pp. 33 and 36 of Extended Prelude to Programming: Concepts and Design (2nd ed.). Refer also to the Input and Output Process Example in Appendix B to see how more detailed analysis and design relates to the previously constructed IPO chart.
The following information demonstrates all the items you need to develop for your programming assignments and for the final project.
Analysis
Process:
1. Get user input
2. Find room area
3. Divide room area
4. Multiply gallons
5. Prompt for ounces
6. Display total
price (real: 0-100)
squareFeetPerGal (real: 0-1000)
width (real: 0-100)
length (real: 0-100)
height (real: 0-100)
Input:
Output:
total_cost (real: > 0)
Design
Main Module
Declare price as real
Declare squareFeetPerGal as real
Declare width as real
Declare length as real
Declare height as real
Declare totalArea as real
Declare gallonsNeeded as real
Declare outputPrompt as string
Declare totalCost as real
Get user input
Find room area
Divide room area
Multiply gallons
Display total
End Main Module
Input Data Module
Write, "What is the price per gallon of paint?"
Input price
Write, "How many square feet does each gallon cover?"
Input square_feet_per_gal
Write, "What is the height of the walls?"
Input height
Write, "What is the width of the walls?"
Input width
Write, "What is the length of the walls?"
Input length
End Input Data Module
Find Room Area Module
Declare sideArea as real
Declare frontBackArea as real
Declare ceilingArea as real
sideArea = 2*(length * height)
frontBackArea = 2*(width * height)
ceilingArea = width * length
totalArea = sideArea + frontBackArea + ceilingArea
End Find Room Area Module
A table is in 2NF when it is in 1NF and it includes no partial dependencies. However a table in 2NF may still have transitive dependencies, i.e., dependencies based on attributes that are not part of the primary key.
What are roles of data administrator in database environment?
http://pkirs.utep.edu/cis4365/Tutorials/Database%20Administration/8.00700/1_multipart_xF8FF_2_tutorial.htm
What are Problems of manual systems?
Accuracy, Ability to reliably update data and take action on trigger events Time it takes to manage the data time it takes to retrieve the data, make updates, ect. Ability to share the data. and the time it takes to share the data. As an example someone in another office needs to know something about a customer. Now they would need to call you, wastes everybodies time. The person should be able to lookup the data in the amount of time it takes to dial the phone.
What is completeness constraint?
Completeness Constraint. * The Completeness Constraint addresses the issue of whether or not an occurrence of a Supertype must also have a corresponding Subtype occurrence. * The Total Specialization Rule specifies that this is the case. This is diagrammed with a double line from the Supertype to the circle as shown here. * The Partial Specialization Rule is the one we have followed thus far in the notes (single line to the circle) -- no such constraint exists. You can have a Supertype named VEHICLE and a Subtype named AUTO, but an occurrence of a vehicle need not be an automobile.
The Greek letter sigma is used to denote a selection operation:
select * from foo
where bar = 10;
When is database not a database?
a database is information storing system where you can store information organized. you can make table for different categories and different topic. you also can relate different type of data each other by using some unique key. ( www.databizsofware.com ) Now a days every database are based on relational database system. each table hold different yet interrelated information. they stay connected with each other by unique key.
isitak
databizsoftware.com
What is a client module in DBMS?
The clients are the various apps that run on top of the DBMS-both user written apps and built in apps.Clients are also known as front ends in DBMS.For example when we use our gmail account for mailing etc. then we basically send and retrieve information from client machines of Google Database.
A functional dependency X --> Y is full functional dependency if removal of any attribute 'k' from X means that the dependency does not hold any more.
Full functional dependency is minimal in size (contain non-redundant data)
In a relation R , attribute B of R is fully functionallydependent on an attribute or set of attributes A of R , if B is functionally dependent on A, but not functionally dependent on any proper subset of A.
OR
AàB is a fully functionally dependency, if removal of any attribute X from A would result into the cancellation of dependency. i.e. (A-{X})-->B does not hold.
