order by
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Curs Baze de date |
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CUPRINS pag
0. Introducere Aplicaţii tradiţionale bazate pe fişiere; limitări 3 1. Sisteme de Gestiune ale Bazelor de Date (SGBD) 1. 1. Istoric,comentarii 5 1. 2. Definirea sistemelor de gestiune a bazelor de date relaţionale 6 1. 3. Regulile luiCodd 7 1. 4. Criterii minimale de definire a unui SGBDR 10 1. 5. Abstractizarea datelor 12 1. 6. Scheme, corespondenţe şi instanţe 14 1. 7. Independenţa datelor 15 1. 8. Principalele componente ale unui SGBD 15 1. 9. Obiectivele unui SGBD 18 1.10.Funcţiunile unui SGBD 20 2. Modele de descriere a datelor şi modelarea conceptuală 2.1. Generalităţi, enumerări 25 2.2. Modelare E-R 2.2.1.Concepte de bază 27 2.2.2.Restricţii structurale 31 2.2.3. Chei 34 2.3. Modelul EE-R 2.3.1. Problemele modelului E-R 35 2.3.2. Superclase şi subclase ale tipurilor de entitate 36 2.3.3. Specializarea 37 2.3.4. Generalizarea 38 2.3.5. Condiţii impuse specializării şi generalizării 38 3. Algebra relaţionala 3.1. Structura relaţionala a datelor 3.1.1. Domeniu 38 3.1.2. Relaţie 39 3.1.3. Atribut 40 3.1.4. Operatorii modelului relaţional 41 3.2. Algebra relaţională şi extensiile sale 41 4. Limbaje de interogare comerciale (modelul relaţional) - SQL 4.1. Istoric, obiective 49 4.2. Clauze şi operatori SQL 4.2.1.Clauzele SELECT, FROM şi WHERE 50 4.2.2.Ordonarea tuplelor (clauza order by 55 4.2.3.Gruparea rezultatelor (clauza GROUP by 56 4.2.4.Interogări pe mai multe tabele 58 4.2.5.Subinterogări 59 4.2.6.Operatorii ANY şi ALL 62 4.2.7.Operatorul EXISTS 64 5. Normalizarea 5.1.Redundanţa informaţiilor şi anomalii de actualizare 66 5.2.Dependenţe funcţionale 69 5.3.Forme normale 5.3.1.Prima formă normală 72 5.3.2.A doua formă normală 74 5.3.3.A treia forma normală 76 5.3.4.Forma normală Boyce-Codd 76 6. Ghid de proiectare al bazelor de date relaţionale 6.1. Metodologia 6.1.1. Metodologia proiectării bazelor de date 80 6.1.2. Prezentarea metodologiei 80 6.1.3. Crearea modelului logic 82 6.2. Proiectarea logică a bazei de date – Exemplu 98 6.3. Utilizarea metodologiei de proiectare a bazelor de date relaţionale 101 6.3.1. Anexa. Documentarea tipurilor de entităţi în view-urile Locatari şi Cheltuieli 118 6.3.2. Anexa. Documentarea atributelor 119 6.3.3. Anexa. Documentarea tipurilor de relaţii din view-urile “Locatari” şi “Cheltuieli 120 6.3.4. Anexa. Documentarea domeniilor atributelor 121 6.3.5. Anexa Descrierea relaţiilor din view-urile “Locatari” şi “Cheltuieli 121 6.3.6. Anexa. Regulile date de întreprindere în cazul modelului “Locatari” şi “Cheltuieli 122 6.3.7. Anexa. Modelul global de date al sistemului Asociaţia de Locatari 122 7. Baze de date distribuite 7.1.Generaliăţi 124 7.2.Arhitectura unui SGBD distribuit 126 7.3.Proiectarea unei baze de date relaţionale distribuite 129 7.4.Alocarea datelor 130 7.5.Transparenţe în SGBDD 133 8. Securitate şi integritate 8.1. Integritate 142 8.2. Securitate 146 9. Tranzacţii şi concurenţă. 9.1.Tranzacţii 151 9.2. Proprietăţile tranzacţiilor 152 9.3. Controlul concurenţei 152 9.4. Tehnici optimiste 158 9.5. Controlul recuperării 159 Test de autoevaluare 162 . Baze de date |
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Baze de date Numar pagini: 161
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SQL |
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5.1. Comanda SELECT
5.1.1. Atributele comenzii SELECT 5.1.2. Operatori aritmetici 5.1.3. Aliasuri de coloane 5.1.4. Operatorul de concatenare 5.1.5. Convertirea valorilor Null cu ajutorul funcţiei NVL 5.1.6. Prevenirea selectării înregistrărilor duplicate 5.1.7. Clauza order by 5.1.8. Clauza WHERE 5.1.9. Operatori relaţionali 5.1.10. Operatori SQL 5.1.11. Operatorii logici 5.1.12. Funcţii 5.1.13. Funcţii referitoare la o singură înregistrare 5.1.14. Functii referitoare la mai multe înregistrari 5.1.15 Pseudo-coloana ROWNUM 5.1.16. Clauza GROUP by 5.1.17. Clauza HAVING 5.1.18. Regasirea datelor din doua sau mai multe tabele 5.1.19. Operatorii pentru mulţimi 5.1.20. Subinterogări şi operatorii ANY, ALL, EXISTS 5.1.21. Operaţii pe tabele ce conţin informaţii do structură arborescentă 5.2 Comanda INSERT 5.3. Comanda UPDATE 5.4. Comanda DELETE 5.5. Comanda TRUNCATE . Sql, comanda, select, aperatori, aritmetici, aliasuri, coloane, concatenare, convertire, valori, null, nvl, prevenire, inregistrari, duplicate, order by, where, clauza, relationali, logici, functii, rownum, group by, having, regasire, date, tabele, multimi, subinterogari, any, all, exists, structura, arborescenta, insert, update, delete, truncate |
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Baze de date Numar pagini: 42
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Descartes |
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In the Meditations, Descartes embarks upon what Bernard Williams
has called the project of 'Pure Enquiry' to discover certain, indubitable foundations for knowledge. by subjecting everything to doubt Descartes hoped to discover whatever was immune to it. In order to best understand how and why Descartes builds his epistemological system up from his foundations in the way that he does, it is helpful to gain an understanding of the intellectual background of the 17th century that provided the motivation for his work. Bibliography 1. Descartes, Ren_ A Discourse on Method, Meditations and Principles of Philosophy trans. John Veitch. The Everyman's Library, 1995. Descartes, Ren_ The Philosophical Writings of Descartes volume I and II ed. and trans. John Cottingham, R. Stoothoff and D. Murdoch. Cambridge, 1985. Frankfurt, Harry Demons, Dreamers and Madmen. Bobbs-Merrill, 1970. Curley, Edwin Descartes Against the Skeptics. Oxford, 1978. Vesey, Godfrey Descartes: Father of Modern Philosophy. Open University Press, 1971. Sorrell, Tom Descartes: Reason and Experience. Open University Press, 1982. The Oxford Companion to Philosophy ed. Ted Honderich. Oxford University Press, 1985. Cottingham, John Descartes. Oxford, 1986. Williams, Bernard Descartes: The Project of Pure Enquiry. Harmondsworth, 1978. Russell, Bertrand The History of Western Philosophy. George Allen and Unwin, 1961. 11. Kripke, Saul Naming and Necessity. Oxford 1980. . Descartes |
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Eating Disorders |
| Eating Disorders Anorexia Nervosa: A condition characterized by intense fear of gaining weight or becoming obese, as well as a distorted body image, leading to an excessive weight loss from restricting food intake and excessive exercise. Bulimia Nervosa: An eating disorder in which persistent overconcern with the body weight and shape leads to repeat episodes of bingeing (consuming large amounts of food in a short time) associated with induced vomiting. Those are the clinical definitions for eating disorders, the definitions that most people think of when they hear one of the two names. Unfortunately, that’s as far as their thoughts go. Almost no one thinks about what causes them, how the disorders are treated, or, most importantly, what it’s like to have one.............. Eating, disorders |
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Frued |
| 1. Freud defines three stages of sexuality, the oral, the anal and the oedipal stage. An infant in its oral stage learns that there is an external world through pleasure and pain. Human nature is governed by the pleasure principle. When the infant is being breast fed he/she feels pleasure and when pulled away from the breast the baby feels pain. The pleasure principle is a way of seeking pleasure in order to avoid pain. We can’t be happy all the time because three things threaten us. First of all our own bodies can’t handle too much pleasure at once, eventually our bodies get older and death is inevitable. Second, natural phenomenon’s get in our way, and third our relationships with others. We are emotionally dependent on others and when we take their words into consideration we become unhappy. Since we can’t be happy all the time we need to learn how to avoid pain. There are five ways we can avoid pain. We can become hedonistic and gain pleasure at all costs all the time. This way of avoiding pain isn’t really possible due to the fact that we wouldn’t be able to accomplish anything else in our lives. Second way of avoiding pain is by voluntary isolation. A person can take him/herself out of society and ................. Frued |
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Multiple Personality Disorder |
| More than two million cases can be found altogether in psychological and psychiatric records of multiple personality disorder also called dissociative identity disorder. It is often thought that multiple personality disorder is a trick, a bizarre form of "play-acting" that is committed by manipulative, attention-seeking individuals. It is not. Multiple personality disorder is a "disorder of hiding" wherein 80-90% of multiple personality disorder patients do not have a clue that they have the disorder. Most know that there is something wrong with them; many fear that they are crazy, but few know that they have a disorder.. Multiple, personality, disorder |
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Lord of the Flies by William Golding |
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Materialul contine rezumatul romanului cu scurte comentarii mai mult biografice.
"The novel Lord of the Flies by William Golding, an adventure and suspense story, is written in 1857. The story sets on an deserted Pacific coral island. A group of school boys are marooned on this island after a plane crash on a trip to Australia. The story begins with a large number of school boys on an uninhabited tropical island and two of the elder boys who have leadership qualities compete to achieve a semblance of order so as to survive.". Lord, of, the, flies, william, golding, short, rezumat, novel, summary, epitome, resume, book report |
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Narcissism |
| The so called ‘narcissistic personality disorder’ is a complex and often misunderstood disorder. The cardinal feature of the narcissistic personality is the grandiose sense of self importance, but paradoxically underneath this grandiosity the narcissist suffers from a chronically fragile low self esteem. The grandiosity of the narcissist, however, is often so pervasive that we tend to dehumanize him or her. The narcissist conjures in us images of the mythological character Narcissus who could only love himself, rebuffing anyone who attempted to touch him. Nevertheless, it is the underlying sense of inferiority which is the real problem of the narcissist, the grandiosity is just a facade used to cover the deep feelings of inadequacy. The Makeup of the Narcissistic Personality The narcissist’s grandiose behavior is designed to reaffirm his or her sense of adequacy. Since the narcissist is incapable of asserting his or her own sense of adequacy, the narcissist seeks to be admired by others. However, the narcissist’s extremely fragile sense of self worth does not allow him or her to risk any criticism. Therefore, meaningful emotional interactions with others are avoided. by simultaneously seeking the admiration of others and keeping them at a distance the narcissist is usually able to maintain the illusion of grandiosity .................. Narcissism |
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1984 - George Orwell |
| "Living in a society with limited freedom of expression is not, in any case, enjoyable. A Totalitarian society is a good example of such a society, because although it provides control for the people, it can deny them a great deal of freedom to express themselves. The fictional society in George Orwell’s 1984 also stands as a metaphor for a Totalitarian society. Communication, personal beliefs, and individual loyalty to the government are all controlled by the inner party which governs the people of Oceania in order to keep them from rebelling." . Book review, george orwell, 1984 |
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Anorexia And What Causes It |
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Eating disorders are not new. Anorexia Nervosa was first formally diagnosed in 1874, and the symptoms have been observed as far back as 300 years ago.(Walsh and Devlin 1) Although the condition has been known for centuries, it seems to be center stage now during the last decade or so.
What is behind Anorexia? Is it inherited? Is Anorexia caused by some type of mental illness, or maybe environmental pressures? Does culture play a role in whether or not someone suffers from Anorexia? These questions are not easily answered,as we know if we have had any family members or close friends who have suffered from Anorexia. It's not as easily diagnosed as the measles or chickenpox, where the doctor knows exactly what the cause is. We will discover that there is no one clearcut cause for Anorexia. According to Women's Health Weekly one research study collected blood from 200 families where at least two of the siblings were suffering from Anorexia, several of the test results suggest a possible link between Anorexia and a shared suseptability gene found in many of the siblings (10) . We must keep in mind that although this research is promising it is still as of yet incomplete data, which in essence makes it a theory. This by no means suggests that there is not a biological link, but that more research needs to be done. . Anorexia |
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Phobias |
| Everyone is afraid of something. Everyone experiences nervousness, anxiety and even in superior feelings around certain people. Some people possess these feelings so deeply that their fear is considered irrational. Even they realize that it is irrational and that they have a phobia. Millions of people suffer from phobias every day of their lives. The third largest psychological disorder in the United States is what psychologists have labelled a social phobia. A social phobia is the fear of social situations and the interactions with other people that can automatically bring on feelings of self-consciousness, judgement, evaluation, and scrutiny. They cannot overcome a social phobia without the patient first grasping exactly what triggers their fears, and then learning how to receive proper help. A social anxiety disorder or social phobia is the constant fear of being criticized or evaluated by other people. People with a social phobia are nervous, anxious, and afraid about many social situations. Simply attending a business meeting or going to a company party can be highly nerve wracking and intimidating. Although people with social anxiety want very much to be social with everyone else, their anxiety about not doing well in public is strong and hinders their best efforts. They freeze up when they meet new people, especially authority figures. They are particularly afraid that other people ............... Phobias |
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An Analysis of the Novel Candide by Voltaire |
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The novel Candide by Voltaire is a great peice of satire that makes fun
of the way people in medievil times thought. The book is about a man, Candide, and his misfortunes. Throughout the book Candide has countless things go wrong in order to show that this is not "the best of all possible worlds" Voltaire is trying to make a point through the exaggeration of the inhumanities of man in a humorous way. . Candide, voltaire, analysis |
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Bulimia Nervosa |
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Bulimia nervosa is defined as two or more episodes of binge eating (rapid consumption of a large amount of food, up to 5,000 calories) every week for at least three months. The binges are sometimes followed by vomiting or purging and may alternate with compulsive exercise and fasting. The symptoms can develop at any age from early adolescence to 40, but usually become clinically serious in late adolescence.
Bulimia is not as dangerous to health as anorexia, but it has many unpleasant physical effects, including fatigue, weakness, constipation, fluid retention, swollen salivary glands, erosion of dental enamel, sore throat from vomiting, and scars on the hand from inducing vomiting. Overuse of laxatives can cause stomach upset and other digestive troubles. Other dangers are dehydration, loss of potassium, and tearing of the esophagus. These eating disorders also occur in men and older women, but much less frequently. Women with diabetes, who have a high rate of bulimia, often lose weight after an eating binge by reducing their dose of insulin. According to recent research, this practice damages eye tissue and raises the risk of diabetic retinopathy, which can lead to blindness. . Bulimia, nervosa |
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