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Deepika SaxenaEmail
deepikasaxena18@yahoo.co.in
| | Profile: I am studying for my bachelors degree in Computer Information Systems from AIT. I have a science background with a knowledge of C++. My hobbies are playing basket ball and I like computer programming. I am interested in designing websites, so I am learning PHP programming. Prof. Ashay Dharwadker's Courses (2): | Course | Semester | Grade | | | Information Systems | Fall 2003 | View | | | Database Systems | Fall 2003 | View | |
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Project ID: 4
Course: Database Systems
Topic: Internet Shopping Database
| Description: Group members are me and Kulmeet .We are planning to make an online_shopping database.
you can see kulmeets page for updates.I'll describe the tables of the database.
create database online_shopping;
create table product(pid integer not null, company_name char(20), description char(20), market_price integer, max_you_pay integer, item_name char(10), primary key(pid));
create table orders(oid integer not null, customer_name char(10), account_no integer, email_id char(20), age integer, sex char(10), mobile_no integer, date char(10), primary key(oid));
create table category(cid integer not null, category char(20), primary key(cid));
create table po(pid integer not null, oid integer not null, status char(10), primary key(pid, oid), foreign key(pid) references product, foreign key(oid) references orders);
create table pc(cid integer not null, pid integer not null, no_of_pieces integer, primary key(cid,pid), foreign key(cid) references category, foreign key(pid) references product);
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Seminar ID: 4
Course: Information Systems
Topic: Dennis Ritchie
| | Description: Dennis Ritchie works in the Computing Sciences Research Center of Bell Labs. He developed the C programming language and the UNIX operating system. When he joined in 1967, Bell Labs was a corporation jointly owned by American Telephone and Telegraph Company (AT&T) and its subsidiary, Western Electric. Its official name was Bell Telephone Laboratories, Inc. In 1984, Bell Telephone Laboratories Inc. was dissolved as a corporation and became an integrated unit of AT&T.
References:
Ritchie's Home Page
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Seminar ID: 16
Course: Database Systems
Topic: Error Correcting Codes
| Description: Consider a Hamming code to detect and correct for single-bit errors assuming each codeword contains a seven-bit data field, e.g. an ASCII character.
for example. Such a coding scheme requires four check bits since, with this scheme, the check bits occupy all bit positions that are powers of 2.
Such a code is thus known as an block code .
For example, the bit positions of the value 1001101 are:
Bit Position 11 10 9 8 7 6 5 4 3 2 1
Bit value 1 0 0 x 1 1 0 x 1 x x
The four bit positions marked with x are used for the check bits, which are derived as follows. The four-bit binary numbers corresponding to those bit positions having a binary 1 are added together using modulo 2 arithmetic and the four check bits are then the four-bit sum:
11 = 1011
7 = 0111
6 = 0110
3 = 0011
1001
The transmitted codeword is thus:
Bit Position 11 10 9 8 7 6 5 4 3 2 1
Bit value 1 0 0 1 1 1 0 0 1 0 1
http://www.cs.ucl.ac.uk/staff/S.Bhatti/D51-notes/node33.html
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Research Note ID: 2
Course: Database Systems
Topic: Data Mining
| | Description: Data Mining is the process of finding new and potentially useful knowledge from a database.It ia an old concept used for finding data in effective manner Data mining is also a process of information extraction activity whose goal is to discover hidden facts contained in databases. Using a combination of machine learning, statistical analysis, modeling techniques and database technology, data mining finds patterns and subtle relationships in data and infers rules that allow the prediction of future results. Typical applications include market segmentation, customer profiling, fraud detection, evaluation of retail promotions, and credit risk analysis.
References:
http://www.twocrows.com/about-dm.htm
http://www.kDnuggets.com
http://www.digimine.com |
Research Note ID: 27
Course: Database Systems
Topic: concurrency
| Description: CONCURRENCY IN DATABASES :
In my opinion this term means that there are many transations made to access the same database at same time.It means that there are n number of transactions at a time on same database.For example, lets take our my students database which anybody can easily use to make transactions at a time.By transactions what i intend to mean is the data entry done by the users.In a huge database some concurrency control mechanism is required to prevent the concurrent transactions from interfering with one another.
The problems faced when there is no concurrency control are:
1. Lost update.
2. Uncommited dependency.
3. Inconsistent Analysis
These problems arise as time schedule are not serializable-i.e., not equivalent to some serial schedule involving the same transactions.
The most used approach for solving such problems is by locking.There are two basic types of locks, shared (S) and exclusive (X) .These locks ensure serializability.This is done by acquiring an S lock on everything updated and acquire an X lock on things updated, and keep all locks until end-of-transaction.A serializable schedule implies that if A and B are any two transactions in a schedule, then eiher A can see B's output or vice versa.This protocol can lead to a deadlocks which can be removed by removing all of its locks.
http://citeseer.nj.nec.com/context/508689/0.html
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Last updated on Thursday, 20th November 2003, 01:32:43 PM.
Prof. Ashay Dharwadker
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