0
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
DFD diagram for hostel management system?
Please follow the URL given below to get the file for DFD of Hostel Management System.I hope this will be useful to you guys. All the best for your projects.For further details contact me at my email ajit.mohapatra@gmail.com
http://rapidshare.com/files/299589924/DFD.docx
Introduction of hotel management system?
Management control systems in hotels implement the ways that lighting is set in a hotel. The control systems also gets feedback from customers and uses that to make improvements for the hotel.
What type of money was used in the 1500's?
It depends on what country/state you are talking about and also who was the ruler at the time. Each new monarch/pope of an area had coins minted with their face or insignia. New coins came out constantly. In Italy gold and silver were used in the form of crowns but in books from the time period there are references of pennies, shillings, farthings and even notes of credit; which were just pieces of paper endorsed by a official. There are mentions of the doubloon also.
An individual trained in the design and building of databases is called a database?
A database designer or database administrator.
Advantages of electronic data processing?
Electronic Data Processing (EDP)
can refer to the use of automated methods to process commercial data. Typically, this uses relatively simple, repetitive activities to process large volumes of similar information. For example: stock updates applied to an inventory, banking transactions applied to account and customer master files, booking and ticketing transactions to an airline's reservation system, billing for utility services.
ADVANTAGES
1. speed
it operates the speed of electric flow which is measured in billions and trillionth of a second. It is faster than any other machine designed to do similar works.
2. Accuracy
High speed processing by computer is accompanied by high accuracy results the electronic circuitry of computer is such that, when the machine are programmed correctly and when incoming data is error free, the accuracy of the output is relatively assured.
3Automatic operation
An electronic computer can carry out sequence of many data processing operations without human interaction, the various operations are executed by way of a stored computer program
4. Decision making capability
A computer can perform certain decision instruction automatically
5. Compact storage
Electronic data processing system have the ability to store large amounts of data in compact and easily retrievable form
6. Discipline imposes
THATS ALL.. HAHAHAHAHA.. soultaker_naruto28@yahoo.com
Difference between real time system versus on line systems?
The prime (and possibly only significant) difference is in the kernel scheduler, which determines which processes get run, with what priority, and for how long.
In a typical "ordinary" OS, the scheduler is some sort of "fair-use" implementation, which insures that no one process monopolizes all the resources if other processes are waiting for CPU time. That is, this kind of scheduler is optimized for interactive use, and the ability to make sure all applications run in a reasonable amount of time.
In a RT OS, all applications are given strict priorities, and the scheduler is designed to give certain characteristics to each priority rating. For instance, it is entirely possible for a RT scheduler to allocate all resources to a single process, and not give anything to any other process, until that process is complete (or does something like block on I/O wait). The based concept behind a RT OS is that certain process priorities are more important than others, and this importance is paramount over any concept of "fair" resource use. In essence, a RT OS prioritizes work in such a manner that certain processes can preempt others and hog resources in ways that a typical OS would consider extremely "unfair". RT OSes are typically optimized for embedded controllers, which are designed to require certain actions be completed immediately, regardless of other demands on the system.
What is a decision support database?
In simple terms it is a database that is used to provide information for a business to help it make decisions. It could be things like sales information on products, their costs of doing business in a particular location or anything like. They will use information that is provided to help make their decisions.
What are the 3 examples of electronic database?
There are examples of electronic databases used in the Public Sector. Firstly, there is the Police Database. The Police use a various amount of databases in order to help solve crime and track criminals. Secondly, there is a Library which stores the details of all books in stock, books borrowed, and members. Finally, there is a Hospital database. Hospitals use databases to track medicines, patients, doctors and schedules. Electronic Databases are now used in all forms of daily life. They allow reliable storage of data, and allow users to quickly obtain the required information from stored data.
Difference between foreign key and composite key?
primary key: primary creates a clustered index on the
column and it doesn't allow null values.
unique key: unique key creates non clustered index by
default.it allows "one null value".
foreign key: A foreign key (FK) is a column or combination
of columns used to establish and enforce a link between the
data in two tables.
Fore More information, you can visit this website:http://www.iyogibusiness.com
Blueprints are usually drawn by an architect. In some cases interior designers will also draw blueprints. The other group of people who regularly draw blueprints is students and apprentices of architecture.
What are the similarities between database and file based system?
These maybe appear to be similar but they have very important differences.
Data Base: It contains a collection of current status of the stored data. The structure is achieved by organising the data according to a data base model. Today, the most common model is the rational model. The most important task of on-line operational database system is to perform on-line transaction and query processing. So, these systems are named Online Transactional Processing (OLTP) systems. Moreover, database system support ad-hoc query and online transaction processing, can be used for other purposes such as data warehousing.
Data Warehouse: Data warehouse is a repository of information collected from multiple sources, such as different databases of a company in different places, which stored under a unified schema, over a history of time. Moreover, it is used for decision support and data analysis. It consists of a process of data cleaning, data integration, data transform, data loading, and data refreshing. Data warehouse is used for Online Analytical Processing (OLAP).
The major difference between OLTP and OLAP are summarised as follows:
OLTP is customer-oriented and it's used by clients, and clerks. But, OLAP is market-oriented and is used for data analysis by managers and analysts.
These have different content too, the first one has current data with detail. Furthermore, is easily used for getting decision; however, another one has large amount of historical data, which provides facilities for summarisation, and store information in different levels of granularity. Because of their huge volume, OLAP data are stored on multiple storage media.
The main similarity is that both of them are repositories of information, storage large amounts of data.
What are the different approaches to database design?
DBMS Three-Schema Architecture and Data Independence
WHAT IS DBMS ?
- To be able to carry out operations like insertion, deletion and retrieval, the database needs to be managed by a substantial piece of software; this software is usually called a Database Management System(DBMS).
- A DBMS is usually a very large software package that enables many different tasks including the provision of facilities to enable the user to access and modify information in the database.
- Data Description Languages (DDL) and Data Manipulation Languages (DML) are needed for manipulating and retrieving data stored in the DBMS. These languages are called respectively.
An architecture for database systems, called the three-schema architecture was proposed to help achieve and visualize the important characteristics of the database approach.
THE THREE-SCHEMA ARCHITECTURE:
The goal of the three-schema architecture is to separate the user applications and the physical database. In this architecture, schemas can be defined at 3 levels :
1. Internal level or Internal schema : Describes the physical storage structure of the database. The internal schema uses a physical data model and describes the complete details of data storage and access paths for the database.
2. Conceptual level or Conceptual schema : Describes the structure of the whole database for a community of users. It hides the details of physical storage structures and concentrates on describing entities, data types, relationships, user operations, and constraints. Implementation data model can be used at this level.
3. External level or External schema : It includes a number of external schemas or user views. Each external schema describes the part of the database that a particular user is interested in and hides the rest of the database from user. Implementation data model can be used at this level.
IMPORTANT TO REMEMBER :
Data and meta-data
- three schemas are only meta-data(descriptions of data).
- data actually exists only at the physical level.
Mapping
- DBMS must transform a request specified on an external schema into a request against the conceptual schema, and then into the internal schema.
- requires information in meta-data on how to accomplish the mapping among various levels.
- overhead(time-consuming) leading to inefficiencies.
- few DBMSs have implemented the full three-schema architecture.
DATA INDEPENDENCE
The disjointing of data descriptions from the application programs (or user-interfaces) that uses the data is called data independence. Data independence is one of the main advantages of DBMS. The three-schema architecture provides the concept of data independence, which means that upper-levels are unaffected by changes to lower-levels. The three schemas architecture makes it easier to achieve true data independence. There are two kinds of data independence.
- Physical data independence
* The ability to modify the physical scheme without causing application programs to be rewritten.
* Modifications at this level are usually to improve performance.
- Logical data independence
* The ability to modify the conceptual scheme without causing application programs to be rewritten.
* Usually done when logical structure of database is altered.
Logical data independence is harder to achieve as the application programs are usually heavily dependent on the logical structure of the data. An analogy is made to abstract data types in programming languages.
What is Cycle of data processing how does it work?
Data processing is a process in which raw data is converted in usable format or information
Data processing cycle - data is processed again and again to get desired or accurate results
for more details visit - http://www.relyservices.com
What type of Images of context diagram for railway reservation system?
first select train and time of train ,reaching area
What is electronic data processing?
The example of electronic data processing is the use of the computer in processing data.
What did the oracle of telemus prophesy?
He warned the Cyclops Polyphemus that the giant would lose his sight to a man named Odysseus.
What are the disadvantages of knowledge based systems?
These are the only two I can come up with:
**Inability to deliver the expected performance outcomes
**Usability: Some users are not capable enough to use automated tools to get required information.
If anyone has more disadvantages please let me know. Thanks
Examples of manual-mechanical data processing?
Yes or no, depending on what the task is. As an example, if you are inputting data into a computer via keyboard, magnetic tape, hard disk file transfer, or keypunch card, the task is completely mechanical.
On the other hand, if you are performing a data processing task related to reading a printed report and manually compiling data, it is not at all mechanical.
Which language is the most suitable for computer programming?
Binary code is the computers language.
For example you sent 300mb from Drive C:/user to D:/Data
The computer could end up transalting this to numbers us 0's and 1's.
