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Relational model

The relational model for database management is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd, where all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a relational database; the purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, let the database management system software take care of describing data structures for storing the data and retrieval procedures for answering queries. Most relational databases use the SQL data query language. A table in an SQL database schema corresponds to a predicate variable. However, SQL databases deviate from the relational model in many details, Codd fiercely argued against deviations that compromise the original principles.

The relational model's central idea is to describe a database as a collection of predicates over a finite set of predicate variables, describing constraints on the possible values and combinations of values. The content of the database at any given time is a finite model of the database, i.e. a set of relations, one per predicate variable, such that all predicates are satisfied. A request for information from the database is a predicate. Other models include the hierarchical network model; some systems using these older architectures are still in use today in data centers with high data volume needs, or where existing systems are so complex and abstract that it would be cost-prohibitive to migrate to systems employing the relational model. Of note are newer object-oriented databases. There have been several attempts to produce a true implementation of the relational database model as defined by Codd and explained by Date and others, but none have been popular successes so far; as of October 2015 Rel is one of the more recent attempts to do this.

The relational model was the first database model to be described in formal mathematical terms. Hierarchical and network databases existed before relational databases, but their specifications were informal. After the relational model was defined, there were many attempts to compare and contrast the different models, this led to the emergence of more rigorous descriptions of the earlier models. Structural database analytics employing relational modality protocols employ data sequence differentials to maintain hierarchical architecture designations with incorporation of new input; these systems are functionally similar in concept to alternative relay algorithms, which form the foundation of cloud database infrastructure. The relational model was invented by Edgar F. Codd as a general model of data, subsequently promoted by Chris Date and Hugh Darwen among others. In The Third Manifesto Date and Darwen attempt to show how the relational model can accommodate certain "desired" object-oriented features.

Some years after publication of his 1970 model, Codd proposed a three-valued logic version of it to deal with missing information, in his The Relational Model for Database Management Version 2 he went a step further with a four-valued logic version. These have never been implemented because of attending complexity. SQL's NULL construct was intended to be part of a three-valued logic system, but fell short of that due to logical errors in the standard and in its implementations; the fundamental assumption of the relational model is that all data is represented as mathematical n-ary relations, an n-ary relation being a subset of the Cartesian product of n domains. In the mathematical model, reasoning about such data is done in two-valued predicate logic, meaning there are two possible evaluations for each proposition: either true or false. Data are operated upon by means of a relational calculus or relational algebra, these being equivalent in expressive power; the relational model of data permits the database designer to create a consistent, logical representation of information.

Consistency is achieved by including declared constraints in the database design, referred to as the logical schema. The theory includes a process of database normalization whereby a design with certain desirable properties can be selected from a set of logically equivalent alternatives; the access plans and other implementation and operation details are handled by the DBMS engine, are not reflected in the logical model. This contrasts with common practice for SQL DBMSs in which performance tuning requires changes to the logical model; the basic relational building block is the domain or data type abbreviated nowadays to type. A tuple is an ordered set of attribute values. An attribute is an ordered pair of type name. An attribute value is a specific valid value for the type of the attribute; this can be a more complex type. A relation consists of a body. A heading is a set of attributes. A body is a set of

Margaret W. Burcham

Margaret W. Burcham is a retired American brigadier general, she was the first female brigadier general in the U. S. Army Corps of Engineers. Margaret W. Burcham attended the United States Military Academy at West Point and was commissioned from there into the United States Army Corps of Engineers in 1982, she holds a masters degree in computer science from Kansas State University and is married to Jay Burcham. Burcham attended the Engineer Officer Basic and Advanced Courses and studied at the Combined Arms Services Staff School, the United States Army Command and General Staff College, the Senior Service College and the Industrial College of the Armed Forces. Burcham has been chief of the Joint Capabilities Division of the Resources and Force Management Directorate at the Pentagon and commander of the USACE North Engineer District in Iraq and the Europe Engineer District, she was appointed commander of the USACE Great Lakes and Ohio River Division in September 2011, the first woman to command a USACE division.

In this role, Burcham commanded 4,800 personnel in seven engineering districts covering 17 states and including the waters within the Great Lakes and Ohio River basins. Her annual budget was $2 billion and the division's responsibilities included the maintenance of navigational aids, flood defense projects, water conservation schemes, hydro-electric power and environmental restoration projects of an asset value of over $80 billion, she was promoted to brigadier general on January 27, 2012 at the USACE headquarters in Washington and became the first female general of the USACE. She was appointed to the Mississippi River Commission on May 2013 by President Barack Obama. Burcham was appointed Director of Manpower and Personnel for the Joint Chiefs of Staff by June 2015, she retired from active duty in August 2016. Media related to Margaret W. Burcham at Wikimedia Commons

Lake Fergus

Lake Fergus is a lake in the South Island of New Zealand, located at 44°50′42″S 168°6′40″E. A small lake between Lake Te Anau and Milford Sound, it lies adjacent to the New Zealand State Highway 94; the lake is within the boundary of the Fiordland National Park, is surrounded by native bush. The west branch of the Eglinton River flows through the lake, it drains into Lake Gunn located south of it; the first Europeans to explore the valley were David McKellar and George Gunn in 1861, two runholders from Southland. William H. Homer and George Barber explored the area in search for a route from Lake Wakatipu to Milford Sound in 1889, setting off from Glenorchy and travelling via the Greenstone Valley, they saw the lake on 4 January, named it after Thomas Fergus, the Member of Parliament for the Wakatipu electorate at the time, left the following inscription in a log: This lake was seen and named on January 4th, 1889,'Lake Fergus', by W. H. Homer and G. Barber. On this journey, the explorers found.

Homer suggested. The Eglington Valley Road past Lake Fergus, now known as SH94, was completed in 1935, giving easy access to the lake for the first time; the Homer Tunnel opened to traffic in 1953, giving visitors reason to drive past Lake Fergus

Charles Paget, 6th Marquess of Anglesey

Lieutenant-Colonel Charles Henry Alexander Paget, 6th Marquess of Anglesey was a British peer and soldier. Paget was born in 1885 to Lord Alexander Paget, third son of Henry Paget, 2nd Marquess of Anglesey, to the Hon. Hester Alice Stapleton-Cotton, daughter of Wellington Stapleton-Cotton, 2nd Viscount Combermere, he was educated at the Royal Military College, Sandhurst. In 1905, he succeeded as Marquess of Anglesey on the demise of his childless cousin, the 5th Marquess, he was Earl of Uxbridge, Baron Paget, the 9th Baronet Paget, of Plas Newydd. Anglesey served in the Royal Horse Guards before his election as Mayor of Burton upon Trent from 1911 to 1912. Within the first month of the First World War, he rejoined the Royal Horse Guards and was sent to France, but was invalided out, he returned to serve as aide-de-camp to Sir John Maxwell, the General Officer Commanding in Egypt – for which he was decorated with the Order of the Nile in 1918 – and to Sir William Birdwood in Gallipoli. He served as Assistant Military Secretary to the General Officer Commanding in Ireland in 1916.

He served in the Home Guard in World War II. The 6th Marquess of Anglesey was Lord Chamberlain to Queen Mary from 1922 until his death in 1947. In the 1928 New Year Honours, he was appointed Knight Grand Cross of the Royal Victorian Order. In 1931, he was invested as an Officer in the Order of Saint John, promoted to Commander of the Order in 1944. During the Second World War, he served in the Home Guard, was Lord Lieutenant of Anglesey from 1942 until his death. On 3 August 1912, he married Lady Victoria Manners, a daughter of the 8th Duke of Rutland, in a grand ceremony performed by the Archbishop of Canterbury and attended by Prince Arthur of Connaught, they had six children: Lady Alexandra Mary Cecilia Caroline Paget, married Sir Michael Duff, 3rd Baronet Lady Elizabeth Hester Mary Paget, married Raimund von Hofmannsthal, son of Hugo von Hofmannsthal Lady Mary Patricia Beatrice Rose Paget, died unmarried Lady Rose Mary Primrose Paget, married Hon. John Francis McLaren George Charles Henry Victor Paget, Earl of Uxbridge Lady Katharine Mary Veronica Paget, married Jocelyn Eustace Gurney, Charles FarrellThe Marquess died in London, aged 61, following an operation.

Until World War I, the 6th Marquess of Anglesey lived at Beaudesert, the Paget family estate and stately home on the southern edge of Cannock Chase in Staffordshire. Heavy taxation after the war meant that the 6th Marquess could no longer afford to maintain the property at Beaudesert, so in 1920 he left to live at Plas Newydd; the Beaudesert estate was broken up and sold off, with the Marquess donating 120 acres of land to the Cannock Chase District in 1920, a further gift in 1938 was made to the people of Staffordshire. At Plas Newydd, the 6th Marquess commissioned the artist Rex Whistler to undertake a decorative mural scheme; the trompe l'oeil paintings and murals and a permanent exhibition of Whistler memorabilia are now one of the major attractions at the property. Hansard 1803–2005: contributions in Parliament by Charles Paget, 6th Marquess of Anglesey

Digital sound revolution

The digital sound revolution refers to the widespread adoption of digital audio technology in the computer industry beginning in the 1980s. Some of the first computer music was created in 1961 by LaFarr Stuart, who wrote software to modulate the duration of and between pulses on a bus line, connected to an amplified speaker installed to monitor the functioning of Iowa State University's CYCLONE computer, a derivative of the Illiac; the entire computer was used to create recognizable tunes using digital audio. The speakers in the IBM PC and its successors may be used to create sounds and music using a similar mechanism. Programmable sound generators were the first specialized audio circuits in computers included simple analog oscillators that could be set to desired frequencies approximating tones along the musical scale. An example of this is the 1978 Atari POKEY custom ASIC used in the Atari 800; the next development was to produce a base frequency, modulating it with another frequency to create desired effects.

This technology was introduced in the early 1980s by Yamaha, which began manufacturing FM synth boards for Japanese computers such as the NEC PC-8801 and PC-9801 in the early 1980s. This allowed personal computer game audio to have greater complexity than the simplistic beeps from internal speakers; these FM synth boards produced a "warm and pleasant sound" that musicians such as Yuzo Koshiro and Takeshi Abo utilized to produce video game music, still regarded within the chiptune community. Early integrated circuit devices to incorporate FM synthesis methods include the Yamaha OPL2 chip set was included on the AdLib sound card, on the Creative Technology Sound Blaster, on the Media Vision Pro AudioSpectrum; as they became more cost-effective, digital-to-analog converter integrated circuits augmented and replaced FM synthesis devices. These devices enabled computers to play digital audio using an encoding technique known as pulse-code modulation. Unlike pulse-width modulation, which turns a signal on and off, pulse-code modulation allows the level of a signal to be set to several intermediate levels.

Digital audio compact discs were introduced in 1982. Starting in 1985, the medium was adapted for the storage of computer data via the Yellow Book CD-ROM standard and the High Sierra Format; the Apple Macintosh and Atari ST could produce digital audio via software. Without dedicated audio hardware, digital audio on these machines were limited to title screens in games or games which did not feature heavy animation which left enough CPU time to play lower quality samples; the first computer to feature a digital sound processor was the Commodore Amiga released in 1985. The MOS Technology 8364 Paula chip featured four independent 8-bit D/A converters and was therefore capable of playing either four mono audio channels or two combined stereo channels; this meant for the first time a computer could play digital samples from memory with no CPU usage, or any clever software tricks. In 1989, the Creative Technology Sound Blaster featured a processor and digital-to-analog converter, incorporated the Yamaha OPL2 chip set FM synthesis devices for compatibility with the AdLib sound card.

In 1991, Media Vision introduced the original Pro AudioSpectrum, which offered similar functionality but introduced stereo sound, an audio mixer and CD-ROM interface. In 1997, Intel Corporation created its Audio CODEC standard AC'97, superseded in 2004 by Intel High Definition Audio. High fidelity audio hardware became inexpensive faster than data storage media, driving the development of compression techniques. A popular early variant of pulse-code modulation was a compressed version called adaptive differential pulse-code modulation. Sound module files enabled music to be created and shared via compact files and played back with high quality. Soon after the release of its Pro AudioSpectrum 16, Media Vision included with it a MOD file player and sample music files. In the late 1990s, the MP3 format emerged, allowing music to be stored in small files by using high compressions rates through a predictive synthesis technique. Modern computer CD-ROM drives allowed the Red Book CD-DA data to be read in digital format, which allows entire volumes of music to be copied and encoded many times faster than normal playback speed.

After the year 2000, strong demand for small portable music players such as Apple's iPods drove competition in component sales, resulting in data storage devices becoming economical. The popularity of high-quality compressed music and the widespread availability of Internet access enabled widespread copyright infringement followed by widespread legitimate sales of music online through the Apple iTunes Music Store,, Walmart


Gampel is a former municipality in the district of Leuk in the canton of Valais in Switzerland. It was an independent municipality until January 1, 2009, when it merged with Bratsch to form Gampel-Bratsch. Gampel is first mentioned in 1238 as Champilz; the blazon of the village coat of arms is Azure in dexter a Mullet of Six Or in sinister an Increscent inverted Argent in base Coupeaux of the second. Gampel has a population of 1,385. Most of the population speaks German as their first language, Albanian is the second most common and Serbo-Croatian is the third. There are 15 people. Of the population in the village 662 or about 50.9% were born in Gampel and lived there in 2000. There were 388 or 29.8% who were born in the same canton, while 65 or 5.0% were born somewhere else in Switzerland, 151 or 11.6% were born outside of Switzerland. As of 2000, there were 547 people who never married in the village. There were 23 individuals who are divorced. There were 147 households that consist of only one person and 44 households with five or more people.

Out of a total of 520 households that answered this question, 28.3% were households made up of just one person and there were 5 adults who lived with their parents. Of the rest of the households, there are 127 married couples without children, 199 married couples with children There were 23 single parents with a child or children. There were 4 households that were made up of unrelated people and 15 households that were made up of some sort of institution or another collective housing. In 2000 there were 177 single family homes out of a total of 331 inhabited buildings. There were 93 multi-family buildings, along with 39 multi-purpose buildings that were used for housing and 22 other use buildings that had some housing. In 2000, a total of 474 apartments were permanently occupied, while 167 apartments were seasonally occupied and 28 apartments were empty; the historical population is given in the following chart: In the 2007 federal election the most popular party was the CVP which received 65.42% of the vote.

The next three most popular parties were the SVP, the SP and the FDP. In the federal election, a total of 804 votes were cast, the voter turnout was 84.9%. As of 2010, Gampel had an unemployment rate of 0%; as of 2008, there were people employed in the primary economic sector and about businesses involved in this sector. No one was employed in the tertiary sector. There were 645 residents of the village who were employed in some capacity, of which females made up 38.9% of the workforce. In 2008 the total number of full-time equivalent jobs was 408; the number of jobs in the primary sector was 17. The number of jobs in the secondary sector was 195 of which 59 or were in manufacturing and 136 were in construction; the number of jobs in the tertiary sector was 196. In the tertiary sector. In 2000, there were 322 workers who commuted into 397 workers who commuted away; the village is a net exporter of workers, with about 1.2 workers leaving the village for every one entering. About 1.9% of the workforce coming into Gampel are coming from outside Switzerland.

Of the working population, % used public transportation to get to work, % used a private car. From the 2000 census, 1,144 or 87.9% were Roman Catholic, while 24 or 1.8% belonged to the Swiss Reformed Church. Of the rest of the population, there were 18 members of an Orthodox church, there were 16 individuals who belonged to another Christian church. There were 60. There were 4 individuals. 8 belonged to no church, are agnostic or atheist, 35 individuals did not answer the question. In Gampel about 481 or of the population have completed non-mandatory upper secondary education, 109 or have completed additional higher education. Of the 109 who completed tertiary schooling, 73.4% were Swiss men, 13.8% were Swiss women, 7.3% were non-Swiss men and 5.5% were non-Swiss women. During the 2010-2011 school year there were a total of 308 students in the Gampel school system; the education system in the Canton of Valais allows young children to attend one year of non-obligatory Kindergarten. During that school year, there 2 kindergarten 42 kindergarten students.

The canton's school system requires students to attend six years of primary school. In Gampel there were 168 students in the primary school; the secondary school program consists of three lower, obligatory years of schooling, followed by three to five years of optional, advanced schools. There were 140 lower secondary students. All the upper secondary students attended school in another municipality; as of 2000, there were 135 students in Gampel who came from another village, while 37 residents attended schools outside the village. Official website Gampel in German, French an