field (redirected from field of study)

field, in algebra

field, in algebra, set of elements (usually numbers) that may be combined under the operations of addition and multiplication so that it constitutes an additive group, the nonzero elements form a multiplicative group, and multiplication distributes over addition. The set of real numbers (see number) and the set of complex numbers are both examples of fields.

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field, in physics

field, in physics, region throughout which a force may be exerted; examples are the gravitational, electric, and magnetic fields that surround, respectively, masses, electric charges, and magnets. The field concept was developed by M. Faraday based on his investigation of the lines of force that appear to leave and return to a magnet at its poles (see flux, magnetic). Fields are used to describe all cases where two bodies separated in space exert a force on each other. The alternative to postulating a field is to assume that physical influences can be transmitted through empty space without any material or physical agency. Such action-at-a-distance, especially if it occurs instantaneously, violates both common sense and certain modern theories, notably relativity, which posits that nothing can travel faster than light. In a field description, rather than body A directly exerting a force on body B, body A (the source) creates a field in every direction around it and body B (the detector) experiences the field that exists at its position. If a change occurs at the source, its effect propagates outward through the field at a constant speed and is felt at the detector only after a certain delay in time. The field is thus a kind of "middleman" for transmitting forces. Each type of force (electric, magnetic, nuclear, or gravitational) has its own appropriate field; a body experiences the force due to a given field only if the body itself it also a source of that kind of field. The reciprocity implied by Newton's third law of motion (equal action and reaction) is thus preserved. If two bodies exert a mutual force, they possess potential energy that depends on their relative positions; it is natural to regard this energy as residing in the field the bodies create.

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field

In physics, a region in which each point is affected by a force. Objects fall to the ground because they are affected by the force of earth's gravitational field (see gravitation). A paper clip, placed in the magnetic field surrounding a magnet, is pulled toward the magnet, and two like magnetic poles repel each other when one is placed in the other's magnetic field. An electric field surrounds an electric charge; when another charged particle is placed in that region, it experiences an electric force that either attracts or repels it. The strength of a field, or the forces in a particular region, can be represented by field lines; the closer the lines, the stronger the forces in that part of the field. See also electromagnetic field.

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field

A physical unit of data that is one or more bytes in size. A collection of fields make up a record. A field also defines a unit of data on a source document, screen or report. Examples of fields are NAME, ADDRESS, QUANTITY and AMOUNT DUE.

The field is the common denominator between the user and the computer. When you interactively query and update your database, you reference your data by field name.

There are several terms that refer to the same unit of storage as a field. A data element is the logical definition of the field, and a data item is the actual data stored in the field. For each data element, there are many fields in the database that hold the data items.

The Basic Unit of Storage

Technically, data elements describe the logical unit of data, fields are the actual storage units, and data items are the individual instances of the data elements as in this example. In everyday language, all three terms are used interchangeably. It's only when you read technical documentation on database management that you run across the proper use of these terms.

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field

1. Sport a limited or marked off area, usually of mown grass, on which any of various sports, athletic competitions, etc., are held

2. Earth Sciences an area that is rich in minerals or other natural resources

3. Hunting the mounted followers that hunt with a pack of hounds

4. Sport

a. all the runners in a particular race or competitors in a competition

b. the runners in a race or competitors in a competition excluding the favourite

5. Cricket the fielders collectively, esp with regard to their positions

6. the area within which an object may be observed with a telescope, microscope, etc.

7. Physics

a. See field of force

b. a region of space that is a vector field

c. a region of space under the influence of some scalar quantity, such as temperature

8. Maths a set of entities subject to two binary operations, addition and multiplication, such that the set is a commutative group under addition and the set, minus the zero, is a commutative group under multiplication and multiplication is distributive over addition

9. Maths logic the set of elements that are either arguments or values of a function; the union of its domain and range

10. Computing

a. a set of one or more characters comprising a unit of information

b. a predetermined section of a record

11. in the field Military in an area in which operations are in progress

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Field

John. 1782--1837, Irish composer and pianist, lived in Russia from 1803: invented the nocturne

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field [fēld]

(computer science)

A specified area, such as a group of card columns or a set of bit locations in a computer word, used for a particular category of data.

(electricity)

That part of an electric motor or generator which produces the magnetic flux which reacts with the armature, producing the desired machine action.

(electronics)

One of the equal parts into which a frame is divided in interlaced scanning for television; includes one complete scanning operation from top to bottom of the picture and back again.

(geology)

A region or area with a particular mineral resource, for example, a gold field.

(geophysics)

That area or space in which a particular geophysical effect, such as gravity or magnetism, occurs and can be measured.

(mathematics)

An algebraic system possessing two operations which have all the properties that addition and multiplication of real numbers have.

(medicine)

The area in which surgery is taking place, bounded on all sides by sterilized tissue or drapes. Also known as sterile field.

(optics)

field of view

(physics)

An entity which acts as an intermediary in interactions between particles, which is distributed over part or all of space, and whose properties are functions of space coordinates and, except for static fields, of time; examples include gravitational field, sound field, and the strain tensor of an elastic medium.

The quantum-mechanical analog of this entity, in which the function of space and time is replaced by an operator at each point in space-time.

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(data, database)

field - An area of a database record, or graphical user interface form, into which a particular item of data is entered. Example usage: "The telephone number field is not really a numerical field", "Why do we need a four-digit field for the year?". A database column is the set of all instances of a given field from all records in a table.