ITGS Syllabus

Monday, April 10, 2006

Topic 54

Key Terms by Chirag Garg

field, key field, record, search, query, sort, database management system, mail merge

Data that has several parts can be divided into fields.

For example, a computer may represent today's date as three distinct fields: the day, the month and the year. Thus, in computer science, things are divided into fields to make it easier for the user to recognize and use them while it also makes it easier for the person that is programming the clock simpler.

A key field is a field or set of fields of a database (typically a relational database) table which together form a unique identifier for a database record (a table entry). The aggregate of these fields is usually referred to simply as "the key".

Row —also called a record represents a single, implicitly structured data item in a table. In simple terms, a database table can be thought of as consisting of rows and columns or fields. Each row in a table represents a set of related data, and every row in the table has the same structure. For example, in a table that represents companies, each row would represent a single company.

Columns might represent things like company name, company street address, whether the company is publicly held, its VAT number, etc. In a table that represents the association of employees with departments, each row would associate one employee with one department. The implicit structure of a row, and the meaning of the data values in a row, requires that the row be understood as providing a succession of data values, one in each column of the table. The row is then interpreted as a relvar composed of a set of record, with each record consisting of the two items: the name of the relevant column and the value this row provides for that column. Each column expects a data value of a particular type. For example, one column might require a unique identifier, another might require text representing a person's name, and another might require an integer representing hourly pay in cents.

A search algorithm, broadly speaking, is an algorithm that takes a problem as input and returns a solution to the problem, usually after evaluating a number of possible solutions. Most of the algorithms studied by computer scientists that solve problems are kinds of search algorithms. The set of all possible solutions to a problem is called the search space. Brute-force search or "naïve"/uninformed search algorithms use the simplest, most intuitive method of searching through the search space, whereas informed search algorithms use heuristics to apply knowledge about the structure of the search space to try to reduce the amount of time spent searching.

There are different types of search methods used in computers:

An uninformed search algorithm is one that does not take into account the specific nature of the problem.

List search algorithms are perhaps the most basic kind of search algorithm. The goal is to find one element of a set by some key.

Tree search algorithms are the heart of searching techniques. These search trees of nodes, whether that tree is explicit or implicit.

Many of the problems in Tree search can be solved using SQL type searches. SQL typically works best on structured data. It offers one advantage over hierarchical type search in that it allows accessing the data in many different ways.

In general, a query is a form of questioning, in a line of inquiry. A query may also refer to:

- A precise request for information, typically keywords combined with Roolean operators and other modifiers, in the field of information retrieval.

- A database query, the standard way information is extracted from databases.

- Query language and database query language, ways of specifying a query.

- Command-Query Separation (CQS), a concept in object-oriented programming, especially in the Eiffel programming language.

- The question mark, especially as used by programmers (analogous to the use of "bang" for the exclamation mark).

- Query (Quaker), a question used for reflection and spiritual exercises among members of the Society of Friends.

- The formal name for a proposal letter (and perhaps accompanying materials) sent by an author to a literary agent or publisher to garner interest in a new work.

A database management system (DBMS) is a system or software designed to manage a database, and run operations on the data requested by numerous clients. Typical examples of DBMS use include accounting, human resources and customer support systems. DBMSs have more recently emerged as a fairly standard part of any company back office. A DBMS is a complex set of software programs that controls the organization, storage and retrieval of data in a database. A DBMS includes A modeling language, A database query language , & A transaction mechanism, that ideally would guarantee the ACID properties, in order to ensure data integrity, despite concurrent user accesses (concurrency control), and faults (fault tolerance).

Mail merge is a computer term describing the production of multiple (and potentially large numbers of) documents from a single template form and a structured data source. This technique is used to create personalized letters and pre-addressed envelopes or mailing labels for mass mailings from a database mailing list of names and addresses.
The procedure of mail merging is typically carried out using a word processing program. The template is a word processing document which contains fixed text that will be the same in each output document variables which act as placeholders to be replaced by text from the data source.


Key Terms by Isaku Oba

Spread sheet programs such as Microsoft Excel have been invented as a systematic method to input and store data. This allowed a more efficient way of storing numerical data, but it also allowed the user to convert the data easily into different formats such as graphs. These programs also allowed users to program equations and calculate new values. What was the significance of these automated functions in terms of daily life? The answer lies in the changes that these programs brought to office work. Before these programs were introduced, companies needed to hire specialized and organized workers who had ability to effectively collect data and reconstruct the bits and pieces into an understandable format.

People who had these skills were not that common at the time, and even the people who were skilled in these aspects took considerable amount of time to complete these tasks. Due to this fact, it was common before for companies to skip organization of data, and keep them in their original format. However, with the introduction of spread sheet programs, ordinary people with no skill were able to do this in a shorter period of time by completing a simple task of punching in numbers in rows and columns.

Thus the spread sheet programs succeeded in significantly increasing the process of office work, and providing more doable jobs for the general unskilled people.
However, the introduction of spread sheet programs was not all benefits which it brought in. It was said, prior to the public introduction of PCs that the public distribution of computers would increase the efficiency of jobs, and therefore decrease the time that workers had to work, for they could complete the same job in the same time. This proved not to be true as corporations gradually increased the amount of work required for their employees, as technology progressed.

This follows a trend of capitalism which was criticized by Karl Marks as an exploitation of the working class by middle class entrepreneurs. The example of spread sheet programs combined with past historical evidence shows that corporal interest is not to lessen the pressure of workers and lift them of their burden, but make them produce as much output as possible. Each time a new technology is introduced, corporate leaders use the cost for introduction of this technology as an excuse to not to lessen their employees’ work hours, where actually the cost is hardly enough to stop the corporate profit from increasing dramatically as technology advances.

This reveals a limitation in the capitalist system that is so accepted in the developed world. In a capitalist society, we consider seeking for profit and seeking economical success stepping on others an accepted idea, and as a result we let ourselves be exploited by greedy corporation, and also create a low working class which makes about 1/100th of what the top10 entrepreneurs make in total. This teaches us a lesson that we must not fall behind technology and let businesses use our ignorance about it as an advantage to maximize their profit while increasingly exploiting us


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