|
Data Dictionary
A data dictionary, or metadata repository, as defined in the ''IBM Dictionary of Computing'', is a "centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format". ''Oracle Corporation, Oracle'' defines it as a collection of tables with metadata. The term can have one of several closely related meanings pertaining to databases and database management systems (DBMS): * A document describing a database or collection of databases * An integral software component, component of a Database management system, DBMS that is required to determine its structure * A piece of middleware that extends or supplants the native data dictionary of a DBMS Documentation The terms ''data dictionary'' and ''data repository'' indicate a more general software utility than a catalogue. A ''catalogue'' is closely coupled with the DBMS software. It provides the information stored in it to the user and the DBA, but it is mainly accessed by the vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Column (database)
In a relational database, a column is a set of data values of a particular type, one value for each row of a table.The term "column" also has equivalent applications in other, more generic contexts. See e.g., Flat file database, Table (information). A column may contain text values, numbers, or even pointers to files in the operating system. Columns typically contain simple types, though some relational database systems allow columns to contain more complex data types, such as whole documents, images, or even video clips. A column can also be called an attribute. Each row would provide a data value for each column and would then be understood as a single structured data value. For example, a database that represents company contact information might have the following columns: ID, Company Name, Address Line 1, Address Line 2, City, and Postal Code. More formally, a row is a tuple containing a specific value for each column, for example: (1234, 'Big Company Inc.', '123 East ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portability (software)
Portability may refer to: *Portability (social security), the portability of social security benefits *Porting, the ability of a computer program to be ported from one system to another in software engineering **Software portability, the portability of a piece of software to alternative platforms *Telephone number portability (other) keeping one telephone number while switching one's account to another telephony provider *Portlet, user interface software components that are managed and displayed in a web portal * Portability of the estate tax exclusion amount regarding Estate tax in the United States In the United States, the estate tax is a federal tax on the transfer of the estate of a person who dies. The tax applies to property that is transferred by will or, if the person has no will, according to state laws of intestacy. Other transfe ... See also * Portable (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foreign Key
A foreign key is a set of attributes in a table that refers to the primary key of another table, linking these two tables. In the context of relational databases, a foreign key is subject to an inclusion dependency constraint that the tuples consisting of the foreign key attributes in one relation, R, must also exist in some other (not necessarily distinct) relation, S; furthermore that those attributes must also be a candidate key in S. In other words, a foreign key is a set of attributes that a candidate key. For example, a table called TEAM may have an attribute, MEMBER_NAME, which is a foreign key referencing a candidate key, PERSON_NAME, in the PERSON table. Since MEMBER_NAME is a foreign key, any value existing as the name of a member in TEAM must also exist as a person's name in the PERSON table; in other words, every member of a TEAM is also a PERSON. Summary The table containing the foreign key is called the child table, and the table containing the candidate ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Library
In computing, a library is a collection of resources that can be leveraged during software development to implement a computer program. Commonly, a library consists of executable code such as compiled functions and classes, or a library can be a collection of source code. A resource library may contain data such as images and text. A library can be used by multiple, independent consumers (programs and other libraries). This differs from resources defined in a program which can usually only be used by that program. When a consumer uses a library resource, it gains the value of the library without having to implement it itself. Libraries encourage software reuse in a modular fashion. Libraries can use other libraries resulting in a hierarchy of libraries in a program. When writing code that uses a library, a programmer only needs to know how to use it not its internal details. For example, a program could use a library that abstracts a complicated system call so that the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Form (programming)
In component-based programming (Visual Basic, .NET WinForms, Gambas, Delphi, Lazarus etc.), a form is a representation of a GUI window. A form contains components and controls, typically including "OK" and "Cancel" buttons; these objects provide a high-level abstraction of standard or custom widgets which are typically much easier to manipulate than the GUI's underlying API. At design time, visual controls (buttons, text boxes, and the like) and non-visual components (timers, database connections, layout aids, and so on) are placed on the form. These controls and components are positioned and sized interactively, and their properties and event handlers are set with a special editor typically laid out as a grid. At runtime, automatically generated code creates instances of these controls and components, and sets their properties. Historically, forms were often implemented as screens on a block-oriented terminal connected to a mainframe computer. HTML forms are conceptually v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menu (computing)
In user interface design, a menu is a list of options presented to the user. Navigation A user chooses an option from a menu by using an input device. Some input methods require linear navigation: the user must move a cursor or otherwise pass from one menu item to another until reaching the selection. On a computer terminal, a reverse video bar may serve as the cursor. Touch user interfaces and menus that accept codes to select menu options without navigation are two examples of non-linear interfaces. Some of the input devices used in menu interfaces are touchscreens, keyboards, mice, remote controls, and microphones. In a voice-activated system, such as interactive voice response, a microphone sends a recording of the user's voice to a speech recognition system, which translates it to a command. Types of menus A computer using a command line interface may present a list of relevant commands with assigned short-cuts (digits, numbers or characters) on the screen. Ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid Application Development
Rapid application development (RAD), also called rapid application building (RAB), is both a general term for adaptive software development approaches, and the name for James Martin's method of rapid development. In general, RAD approaches to software development put less emphasis on planning and more emphasis on an adaptive process. Prototypes are often used in addition to or sometimes even instead of design specifications. RAD is especially well suited for (although not limited to) developing software that is driven by user interface requirements. Graphical user interface builders are often called rapid application development tools. Other approaches to rapid development include the adaptive, agile, spiral, and unified models. History Rapid application development was a response to plan-driven waterfall processes, developed in the 1970s and 1980s, such as the Structured Systems Analysis and Design Method (SSADM). One of the problems with these methods is that they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Framework
In computer programming, a software framework is a software abstraction that provides generic functionality which developers can extend with custom code to create applications. It establishes a standard foundation for building and deploying software, offering reusable components and design patterns that handle common programming tasks within a larger software platform or environment. Unlike libraries where developers call functions as needed, frameworks implement inversion of control by dictating program structure and calling user code at specific points, while also providing default behaviors, structured extensibility mechanisms, and maintaining a fixed core that accepts extensions without direct modification. Frameworks also differ from regular applications that can be modified (like web browsers through extensions, video games through mods), in that frameworks are intentionally incomplete scaffolding meant to be extended through well-defined extension points and followin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Database
A distributed database is a database in which data is stored across different physical locations. It may be stored in multiple computers located in the same physical location (e.g. a data centre); or maybe dispersed over a computer network, network of interconnected computers. Unlike Parallel computing, parallel systems, in which the processors are tightly coupled and constitute a single database system, a distributed database system consists of loosely coupled sites that share no physical components. System administrators can distribute collections of data (e.g. in a database) across multiple physical locations. A distributed database can reside on organised network servers or blockchain (database), decentralised independent computers on the Internet, on corporate intranets or extranets, or on other organisation Computer network, networks. Because distributed databases store data across multiple computers, distributed databases may improve performance at end-user worksites by all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Query Optimization
Query optimization is a feature of many relational database management systems and other databases such as NoSQL and graph databases. The query optimizer attempts to determine the most efficient way to execute a given query by considering the possible query plans. Generally, the query optimizer cannot be accessed directly by users: once queries are submitted to the database server, and parsed by the parser, they are then passed to the query optimizer where optimization occurs. However, some database engines allow guiding the query optimizer with hints. A query is a request for information from a database. It can be as simple as "find the address of a person with Social Security number 123-45-6789," or more complex like "find the average salary of all the employed married men in California between the ages 30 to 39 who earn less than their spouses." The result of a query is generated by processing the rows in a database in a way that yields the requested information. Since data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
