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Database Trigger
A database trigger is procedural code that is automatically executed in response to certain Event (computing), events on a particular Table (database), table or View (database), view in a database. The trigger is mostly used for maintaining the Database integrity, integrity of the information on the database. For example, when a new record (representing a new worker) is added to the employees table, new records should also be created in the tables of the taxes, vacations and salaries. Triggers can also be used to log historical data, for example to keep track of employees' previous salaries. Triggers in DBMS Below follows a series of descriptions of how some popular DBMS support triggers. Oracle In addition to triggers that fire (and execute PL/SQL code) when data is modified, Oracle Database, Oracle 10g supports triggers that fire when schema-level objects (that is, tables) are modified and when user logon or logoff events occur. Schema-level triggers * After Creation * Bef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Procedural Code
Procedural programming is a programming paradigm, classified as imperative programming, that involves implementing the behavior of a computer program as Function (computer programming), procedures (a.k.a. functions, subroutines) that call each other. The resulting program is a series of steps that forms a hierarchy of calls to its constituent procedures. The first major procedural programming languages appeared –1964, including Fortran, ALGOL, COBOL, PL/I and BASIC. Pascal (programming language), Pascal and C (programming language), C were published –1972. Computer processors provide hardware support for procedural programming through a stack register and instructions for Subroutine#Jump to subroutine, calling procedures and returning from them. Hardware support for other types of programming is possible, like Lisp machines or Java processors, but no attempt was commercially successful. Development practices Certain software development practices are often employed with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Firebird (database Server)
Firebird and fire bird may refer to: Mythical birds * Phoenix (mythology), sacred firebird found in the mythologies of many cultures ** Fenghuang, sometimes called Chinese phoenix * Vermilion bird, one of the four symbols of the Chinese constellation representing fire * Bennu, Egyptian firebird * Huma bird, Persian firebird * Firebird (Slavic folklore) Automobiles * Pontiac Firebird, American pony car * General Motors Firebird, series of concept cars Aviation * AAM-A-1 Firebird, an American air-to-air missile of the 1940s * Chengdu J-10 (NATO reporting name: Firebird), a Chinese combat aircraft * Northrop Grumman Firebird, an American recon/surveillance aircraft * CargoLogicAir, a defunct British airline (callsign: FIREBIRD) Film and television * ''Firebird'' (film), a 2021 film directed by Peeter Rebane * ''The Firebird'' (1934 film), a murder mystery directed by William Dieterle * ''The Firebird'' (1952 film), a musical drama film directed by Hasse Ekman * "Fireb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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] |
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Primary Key
In the relational model of databases, a primary key is a designated attribute (column) that can reliably identify and distinguish between each individual record in a table. The database creator can choose an existing unique attribute or combination of attributes from the table (a natural key) to act as its primary key, or create a new attribute containing a unique ID that exists solely for this purpose (a surrogate key). Examples of natural keys that could be suitable primary keys include data that is already by definition unique to all items in the table such as a national identification number attribute for person records, or the combination of a very precise timestamp attribute with a very precise location attribute for event records. More formally, a primary key is a specific choice of a minimal set of attributes that uniquely specify a tuple ( row) in a relation (table). A primary key is a choice of a candidate key (a minimal superkey); any other candidate key is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Recursion (computer Science)
In computer science, recursion is a method of solving a computational problem where the solution depends on solutions to smaller instances of the same problem. Recursion solves such recursion, recursive problems by using function (computer science), functions that call themselves from within their own code. The approach can be applied to many types of problems, and recursion is one of the central ideas of computer science. Most computer programming languages support recursion by allowing a function to call itself from within its own code. Some functional programming languages (for instance, Clojure) do not define any looping constructs but rely solely on recursion to repeatedly call code. It is proved in computability theory that these recursive-only languages are Turing complete; this means that they are as powerful (they can be used to solve the same problems) as imperative languages based on control structures such as and . Repeatedly calling a function from within itse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Delete (SQL)
In the database structured query language ( SQL), the DELETE statement is used to remove one or more records from a table. A subset may be defined for deletion using a condition, otherwise all records are removed. Some database management systems (DBMSs), like MySQL MySQL () is an Open-source software, open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A rel ..., allow deletion of rows from multiple tables with one DELETE statement (this is sometimes called multi-table DELETE). Examples Delete rows from table ''pies'' where column ''flavor'' equals ''Lemon Meringue'': DELETE FROM pies WHERE flavor='Lemon Meringue'; Delete rows in ''trees'', if the value of ''height'' is smaller than 80. DELETE FROM trees WHERE height < 80; Delete all rows from ''mytable'': [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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XPath
XPath (XML Path Language) is an expression language designed to support the query or transformation of XML documents. It was defined by the World Wide Web Consortium (W3C) in 1999, and can be used to compute values (e.g., strings, numbers, or Boolean values) from the content of an XML document. Support for XPath exists in applications that support XML, such as web browsers, and many programming languages. The XPath language is based on a tree representation of the XML document, and provides the ability to navigate around the tree, selecting nodes by a variety of criteria. In popular use (though not in the official specification), an XPath expression is often referred to simply as "an XPath". Originally motivated by a desire to provide a common syntax and behavior model between XPointer and XSLT, subsets of the XPath query language are used in other W3C specifications such as XML Schema, XForms and the Internationalization Tag Set (ITS). XPath has been adopted by a num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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XQuery
XQuery (XML Query) is a query language and functional programming language designed to query and transform collections of structured and unstructured data, primarily in the form of XML. It also supports text data and, through implementation-specific extensions, other formats like binary and relational data. The language was developed by the XML Query working group of the W3C, with version 1.0 becoming a W3C Recommendation in January 2007. XQuery development is closely coordinated with the development of XSLT by the XSL Working Group. Both groups jointly maintain XPath, a shared component of XQuery and XSLT. XQuery extends XPath with features like FLWOR (For, Let, Where, Order by, Return) expressions, making it semantically similar to SQL but optimized for hierarchical rather than relational data. XQuery 3.1, published in March 2017, added support for JSON and introduced maps, arrays, and additional higher-order functions, significantly expanding the language's cap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Sedna (database)
Sedna is an open-source database management system that provides native storage for XML data. The distinctive design decisions employed in Sedna are (i) schema-based clustering storage strategy for XML data and (ii) memory management based on layered address space.Ilya Taranov et al. Sedna: native XML database management system (internals overview). In ACM SIGMOD '10: Proceedings of the 36th international conference on Association for Computing Machinery's Special Interest Group on Management of Data, pages 1037-1045, New York, NY, USA, 2010. ACM. Data organization Data organization in Sedna is designed with the goal of providing a balance in performance between XML queries and updates execution. The two primary design decisions in data organization in Sedna are: # ''Direct'' pointers are used to represent XML node relationships such as parent, child, and sibling ones. Unlike relational-based approaches that require performing joins for traversing an XML document, trav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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SQLite
SQLite ( "S-Q-L-ite", "sequel-ite") is a free and open-source relational database engine written in the C programming language. It is not a standalone app; rather, it is a library that software developers embed in their apps. As such, it belongs to the family of embedded databases. It is the most widely deployed database engine, as it is used by several of the top web browsers, operating systems, mobile phones, and other embedded systems. Many programming languages have bindings to the SQLite library. It generally follows PostgreSQL syntax, but does not enforce type checking by default. This means that one can, for example, insert a string into a column defined as an integer. Although it is a lightweight embedded database, SQLite implements most of the SQL standard and the relational model, including transactions and ACID guarantees. However, it omits many features implemented by other databases, such as materialized views and complete support for triggers and AL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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SQL PL
SQL PL stands for Structured Query Language Procedural Language and was developed by IBM as a set of commands that extend the use of SQL in the IBM Db2 (DB2 UDB Version 7) database system. It provides procedural programmability in addition to the querying commands of SQL. It is a subset of the SQL Persistent Stored Modules (SQL/PSM) language standard. As of DB2 version 9, SQL PL stored procedures can run natively inside the DB2 process (inside the DBM1 address space, more precisely) instead of being fenced in an external process. In DB2 version 9.7 IBM also added a PL/SQL front-end to this infrastructure (called "SQL Unified Runtime Engine"), meaning that procedural SQL using either the ISO standard or Oracle's syntax compile to bytecode running on the same engine in DB2. See also * IBM Db2 * Comparison of relational database management systems The following tables compare general and technical information for a number of relational database management systems. Please see the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |