Field (computer science)

In computer science, data that has several parts, known as a record, can be divided into fields. Relational databases arrange data as sets of database records, also called rows. Each record consists of several fields; the fields of all records form the columns.

In object-oriented programming, field (also called data member or member variable) is the data encapsulated within a class or object. In the case of a regular field (also called instance variable), for each instance of the object there is an instance variable: for example, an Employee class has a Name field and there is one distinct name per employee. A static field (also called class variable) is one variable, which is shared by all instances.

Fixed length

Fields that contain a fixed number of bits are known as fixed length fields. A four byte field for example may contain a 31 bit binary integer plus a sign bit (32 bits in all). A 30 byte name field may contain a persons name typically padded with blanks at the end. The disadvantage of using fixed length fields is that some part of the field may be wasted but space is still required for the maximum length case. Also, where fields are omitted, padding for the missing fields is still required to maintain fixed start positions within a record for instance.

Field (mathematics)

In mathematics, a field is one of the fundamental algebraic structures used in abstract algebra. It is a nonzero commutative division ring, or equivalently a ring whose nonzero elements form an abelian group under multiplication. As such it is an algebraic structure with notions of addition, subtraction, multiplication, and division satisfying the appropriate abelian group equations and distributive law. The most commonly used fields are the field of real numbers, the field of complex numbers, and the field of rational numbers, but there are also finite fields, algebraic function fields, algebraic number fields, p-adic fields, and so forth.

Any field may be used as the scalars for a vector space, which is the standard general context for linear algebra. The theory of field extensions (including Galois theory) involves the roots of polynomials with coefficients in a field; among other results, this theory leads to impossibility proofs for the classical problems of angle trisection and squaring the circle with a compass and straightedge, as well as a proof of the Abel–Ruffini theorem on the algebraic insolubility of quintic equations. In modern mathematics, the theory of fields (or field theory) plays an essential role in number theory and algebraic geometry.

Dial

Dial may refer to:

Mechanical device

DIAL

Other

Dial (band)

Dial is a progressive rock band based in the Netherlands.

History

Dial was founded in late 2003 by Liselotte Hegt, Rommert van der Meer and Kristoffer Gildenlöw. Early on, the band was pure a hobby but after Kristoffer's departure from Swedish prog metal band Pain of Salvation in early 2006, the band headed towards a more serious destiny.

In summer 2006, the band went to Austria to record their debut album Synchronized together with producer Devon Graves (of Deadsoul Tribe and Psychotic Waltz). This album was released in May 2007 through Prog Rock Records (US).

Line-up

External links

Rotary dial

A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing. It is used when initiating a telephone call to transmit the destination telephone number to a telephone exchange.

On the rotary dial, the digits are arranged in a circular layout so that a finger wheel may be rotated with one finger from the position of each digit to a fixed stop position, implemented by the finger stop, which is a mechanical barrier to prevent further rotation. When released at the finger stop, the wheel returns to its home position by spring action at a speed regulated by a governor device. During this return rotation, the dial interrupts the direct electrical current of the telephone line (local loop) a specific number of times for each digit and thereby generates electrical pulses which the telephone exchange decodes into each dialed digit. Each of the ten digits are encoded in sequences of up to ten pulses. For this reason, the method is sometimes called decadic dialling.