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Transaction Time
In temporal databases, transaction time (TT) is the time during which a fact stored in the database is considered to be true. As of December 2011, ISO/IEC 9075, Database Language SQL:2011 Part 2: SQL/Foundation included clauses in table definitions to define "system-versioned tables" (that is, transaction-time tables). In a database table transaction interval is often represented as an interval allowing the system to "remove" entries by using two table-columns ''StartTT'' and ''EndTT''. The time interval is closed at its lower bound and open at its upper bound. When the ending transaction time is unknown, it may be considered as "Until Changed". Academic researchers and some RDBMS have represented "Until Changed" with the largest timestamp supported or the keyword "forever". This convention is not technically precise. The term was coined by Richard T. Snodgrass and his doctoral student Ilsoo Ahn. See also * Valid time In temporal databases, valid time (VT) is the time perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Database
A temporal database stores data relating to time instances. It offers temporal data types and stores information relating to past, present and future time. Temporal databases could be uni-temporal, bi-temporal or tri-temporal. More specifically the temporal aspects usually include valid time, transaction time or decision time. * Valid time is the time period during which a fact is true in the real world. * Transaction time is the time at which a fact was recorded in the database. * Decision time is the time at which the decision was made about the fact. Uni-temporal A uni-temporal database has one axis of time, either the validity range or the system time range. Bi-temporal A bi-temporal database has two axes of time: * valid time * transaction time or decision time Tri-temporal A tri-temporal database has three axes of time: * valid time * transaction time * decision time This approach introduces additional complexities. Temporal databases are in contrast to current databa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2011
File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrates the independence of South Sudan, the world's newest country; the 2011 Tōhoku earthquake and tsunami devastates Eastern Japan and kills nearly 20,000 people; Minecraft is released and goes on to become the best-selling video game; the 2011 Norway attacks mark the rise of white supremacist terrorism across the west; The U.S. national security team gathered in the White House Situation Room to monitor the progress of Operation Neptune Spear that killed Al-Qaeda leader Osama bin Laden; Anti-government protests called the Arab Spring arose in 2010–2011, and as a result, many governments were overthrown in the Middle East and Northern Africa., 300x300px, thumb rect 0 0 200 200 Occupy movement rect 200 0 400 200 Killing of Muammar Gaddaf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Bound
In mathematics, particularly in order theory, an upper bound or majorant of a subset of some preordered set is an element of that is greater than or equal to every element of . Dually, a lower bound or minorant of is defined to be an element of that is less than or equal to every element of . A set with an upper (respectively, lower) bound is said to be bounded from above or majorized (respectively bounded from below or minorized) by that bound. The terms bounded above (bounded below) are also used in the mathematical literature for sets that have upper (respectively lower) bounds. Examples For example, is a lower bound for the set (as a subset of the integers or of the real numbers, etc.), and so is . On the other hand, is not a lower bound for since it is not smaller than every element in . The set has as both an upper bound and a lower bound; all other numbers are either an upper bound or a lower bound for that . Every subset of the natural numbers has a lowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Bound
In mathematics, particularly in order theory, an upper bound or majorant of a subset of some preordered set is an element of that is greater than or equal to every element of . Dually, a lower bound or minorant of is defined to be an element of that is less than or equal to every element of . A set with an upper (respectively, lower) bound is said to be bounded from above or majorized (respectively bounded from below or minorized) by that bound. The terms bounded above (bounded below) are also used in the mathematical literature for sets that have upper (respectively lower) bounds. Examples For example, is a lower bound for the set (as a subset of the integers or of the real numbers, etc.), and so is . On the other hand, is not a lower bound for since it is not smaller than every element in . The set has as both an upper bound and a lower bound; all other numbers are either an upper bound or a lower bound for that . Every subset of the natural numbers has a lowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard T
Richard is a male given name. It originates, via Old French, from Frankish language, Old Frankish and is a Compound (linguistics), compound of the words descending from Proto-Germanic language, Proto-Germanic ''*rīk-'' 'ruler, leader, king' and ''*hardu-'' 'strong, brave, hardy', and it therefore means 'strong in rule'. Nicknames include "Richie", "Dick (nickname), Dick", "Dickon", "Dickie (name), Dickie", "Rich (given name), Rich", "Rick (given name), Rick", "Rico (name), Rico", "Ricky (given name), Ricky", and more. Richard is a common English, German and French male name. It's also used in many more languages, particularly Germanic, such as Norwegian, Danish, Swedish, Icelandic, and Dutch, as well as other languages including Irish, Scottish, Welsh and Finnish. Richard is cognate with variants of the name in other European languages, such as the Swedish "Rickard", the Catalan "Ricard" and the Italian "Riccardo", among others (see comprehensive variant list below). People ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valid Time
In temporal databases, valid time (VT) is the time period during which a database fact is valid in the modeled reality. As of December 2011, ISO/IEC 9075, Database Language SQL:2011 Part 2: SQL/Foundation included clauses in table definitions to define "application-time period tables" (that is, valid-time tables). ''Valid time'' was coined by Richard T. Snodgrass and his doctoral student.Richard T. Snodgrass and Ilsoo Ahn, "Temporal Databases," IEEE Computer 19(9), September, 1986, pp. 35-42. In a database table valid time is often represented by two extra table-columns ''StartVT'' and ''EndVT''. The time interval is closed at its lower bound and open at its upper bound. Example: Valid time is the time for which a fact is true in the real world. In the example above, the Person table gets two extra fields, Valid-From and Valid-To, specifying when a person's address was valid in the real world. On April 4, 1975, John's father proudly registered his son's birth. An official will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decision Time
Decision may refer to: Law and politics *Judgment (law), as the outcome of a legal case *Landmark decision, the outcome of a case that sets a legal precedent * ''Per curiam'' decision, by a court with multiple judges Books * ''Decision'' (novel), a 1983 political novel by Allen Drury * ''The Decision'' (novel), a 1998 book in the ''Animorphs'' series Sports *Decision (baseball), a statistical credit earned by a baseball pitcher * Decisions in combat sports *Decisions (professional wrestling), by which a wrestler scores a point against his opponent Film and TV * ''Decision'' (TV series), an American anthology TV series * ''The Decision'' (play), by the 20th-century German dramatist Bertolt Brecht * ''The Decision'' (TV special), in which NBA player LeBron James announced that he would switch teams * "The Decision" (song), by English indie rock band Young Knives Music Albums * ''Decisions'' (George Adams and Don Pullen album), 1984 * ''Decisions'' (The Winans album), 1987 Songs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Database
A temporal database stores data relating to time instances. It offers temporal data types and stores information relating to past, present and future time. Temporal databases could be uni-temporal, bi-temporal or tri-temporal. More specifically the temporal aspects usually include valid time, transaction time or decision time. * Valid time is the time period during which a fact is true in the real world. * Transaction time is the time at which a fact was recorded in the database. * Decision time is the time at which the decision was made about the fact. Uni-temporal A uni-temporal database has one axis of time, either the validity range or the system time range. Bi-temporal A bi-temporal database has two axes of time: * valid time * transaction time or decision time Tri-temporal A tri-temporal database has three axes of time: * valid time * transaction time * decision time This approach introduces additional complexities. Temporal databases are in contrast to current databa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Management Systems
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. A database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an application ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
