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QUEL Query Languages
QUEL is a relational database query language, based on tuple relational calculus, with some similarities to SQL. It was created as a part of the Ingres DBMS effort at University of California, Berkeley, based on Codd's earlier suggested but not implemented ''Data Sub-Language ALPHA''. QUEL was used for a short time in most products based on the freely available Ingres source code, most notably in an implementation called POSTQUEL supported by POSTGRES. Eugene Wong of Ingres was the creator of QUEL. As Oracle and IBM DB2 gained market share in the early 1980s, Ingres and other companies supporting QUEL moved to SQL. QUEL continues to be available as a part of the Ingres DBMS, although no QUEL-specific language enhancements have been added for many years. Usage QUEL statements are always defined by ''tuple variables'', which can be used to limit queries or return result sets. Consider this example, taken from one of the first original Ingres papers: range of E is EMPL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Query Language
A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. A well known example is the Structured Query Language (SQL). Types Broadly, query languages can be classified according to whether they are ''database'' query languages or ''information retrieval'' query languages. The difference is that a database query language attempts to give factual answers to factual questions, while an information retrieval query language attempts to find documents containing information that is relevant to an area of inquiry. Other types of query languages include: * Full-text. The simplest query language is treating all terms as bag of words that are to be matched with the postings in the inverted index and where subsequently ranking models are applied to retrieve the most relevant documents. Only tokens ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugene Wong
Eugene Wong (born December 24, 1934, in Nanjing, China) is a Chinese-American computer scientist and mathematician. Wong's career has spanned academia, university administration, government and the private sector. Together with Michael Stonebraker and a group of scientists at IBM, Wong is credited with pioneering database research in the 1970s from which software developed by IBM, Microsoft, and Oracle descends. Wong retired in 1994, since then holding the title of Professor Emeritus of Electrical Engineering and Computer Sciences at University of California, Berkeley. The IEEE, as part of an award citation, wrote that Wong "is known for the extraordinary breadth of his accomplishments" and "for leadership in national and international engineering research and technology policy, for pioneering contributions in relational databases." Ingres In 1973, Michael Stonebraker and his colleague Eugene Wong, having read Edgar F. Codd's work regarding the relational data model, began t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Query Languages
A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. A well known example is the Structured Query Language (SQL). Types Broadly, query languages can be classified according to whether they are ''database'' query languages or ''information retrieval'' query languages. The difference is that a database query language attempts to give factual answers to factual questions, while an information retrieval query language attempts to find documents containing information that is relevant to an area of inquiry. Other types of query languages include: * Full-text. The simplest query language is treating all terms as bag of words that are to be matched with the postings in the inverted index and where subsequently ranking models are applied to retrieve the most relevant documents. Only tokens ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Management Systems
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS 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 associated with the database. Before digital storage and retrieval of data have become widespread, index cards were used for data storage in a wide range of applications and environments: in the home to record and store recipes, shopping lists, contact information and other organizational data; in business to record presentation notes, project research and notes, and contact information; in schools as flash card ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relational Calculus
The relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that is part of the relational model for databases and provide a declarative way to specify database queries. The raison d'être of relational calculus is the formalization of query optimization, which is finding more efficient manners to execute the same query in a database. The relational calculus is similar to the relational algebra, which is also part of the relational model: While the relational calculus is meant as a declarative language that prescribes no execution order on the subexpressions of a relational calculus expression, the relational algebra is meant as an imperative language: the sub-expressions of a relational algebraic expression are meant to be executed from left-to-right and inside-out following their nesting. Per Codd's theorem, the relational algebra and the domain-independent relational calculus are logically equivalent. Example A relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relational Algebra
In database theory, relational algebra is a theory that uses algebraic structures for modeling data and defining queries on it with well founded semantics (computer science), semantics. The theory was introduced by Edgar F. Codd. The main application of relational algebra is to provide a theoretical foundation for relational databases, particularly query languages for such databases, chief among which is SQL. Relational databases store tabular data represented as relation (database), relations. Queries over relational databases often likewise return tabular data represented as relations. The main purpose of relational algebra is to define Operator (mathematics), operators that transform one or more input relations to an output relation. Given that these operators accept relations as input and produce relations as output, they can be combined and used to express complex queries that transform multiple input relations (whose data are stored in the database) into a single output rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D4 (programming Language)
Dataphor is an open-source truly-relational database management system (RDBMS) and its accompanying user interface technologies, which together are designed to provide highly declarative software application development. The Dataphor Server has its own storage engine or it can be a virtual, or federated, DBMS, meaning that it can utilize other database engines for storage. Dataphor has been praised for its adherence to relational principles, more closely so than any SQL product. Overview The stated purpose of Dataphor is to attempt to raise the bar of automation when building and maintaining complex software applications. Originally referred to as a framework, Dataphor provides more of a software development platform, complete with its own programming and user interface paradigms. Dataphor is broadly divided into two components: the Dataphor Server, and the Dataphor Frontend. The purpose of the Dataphor Server is to provide a standardized language and runtime for the definiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stored Procedure
A stored procedure (also termed prc, proc, storp, sproc, StoPro, StoredProc, StoreProc, sp, or SP) is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary. Uses for stored procedures include data-validation (integrated into the database) or access-control mechanisms. Furthermore, stored procedures can consolidate and centralize logic that was originally implemented in applications. To save time and memory, extensive or complex processing that requires execution of several SQL statements can be saved into stored procedures, and all applications call the procedures. One can use nested stored procedures by executing one stored procedure from within another. Stored procedures may return result sets, i.e., the results of a SELECT statement. Such result sets can be processed using cursors, by other stored procedures, by associating a result-set locator, or by applications. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Database
Oracle Database (commonly referred to as Oracle DBMS, Oracle Autonomous Database, or simply as Oracle) is a proprietary multi-model database management system produced and marketed by Oracle Corporation. It is a database commonly used for running online transaction processing (OLTP), data warehousing (DW) and mixed (OLTP & DW) database workloads. Oracle Database is available by several service providers on-premises, on-cloud, or as a hybrid cloud installation. It may be run on third party servers as well as on Oracle hardware ( Exadata on-premises, on Oracle Cloud or at Cloud at Customer). Oracle Database uses SQL for database updating and retrieval. History Larry Ellison and his two friends and former co-workers, Bob Miner and Ed Oates, started a consultancy called Software Development Laboratories (SDL) in 1977, later Oracle Corporation. SDL developed the original version of the Oracle software. The name ''Oracle'' comes from the code-name of a CIA-funded proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACM SIGMOD Conference
SIGMOD is the Association for Computing Machinery's Special Interest Group on Management of Data, which specializes in large-scale data management problems and databases. The annual ACM SIGMOD Conference, which began in 1975, is considered one of the most important in the field. While traditionally this conference had always been held within North America, it took place in Paris in 2004, Beijing in 2007, Athens in 2011, and Melbourne in 2015. The acceptance rate of the ACM SIGMOD Conference, averaged from 1996 to 2012, was 18%, and it was 17% in 2012. In association with SIGACT and SIGAI, SIGMOD also sponsors the annual ACM Symposium on Principles of Database Systems (PODS) conference on the theoretical aspects of database systems. PODS began in 1982, and has been held jointly with the SIGMOD conference since 1991. Each year, the group gives out several awards to contributions to the field of data management. The most important of these is the SIGMOD Edgar F. Codd Innovations Awa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Stonebraker
Michael Ralph Stonebraker (born October 11, 1943) is an American computer scientist specializing in database, database systems. Through a series of academic prototypes and commercial startups, Stonebraker's research and products are central to many relational databases. He is also the founder of many database companies, including Actian, Ingres Corporation, Illustra, Paradigm4, StreamBase Systems, Tamr, Vertica, VoltDB and Hopara, and served as chief technical officer of Informix Corporation, Informix. For his contributions to database research, Stonebraker received the 2014 Turing Award, often described as "the Nobel Prize for computing." Stonebraker's career can be broadly divided into two phases: his time at University of California, Berkeley when he focused on relational database management systems such as Ingres (database), Ingres and Postgres, and, starting in 2001, at Massachusetts Institute of Technology (MIT) where he developed more novel data management techniques such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
