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Apache CouchDB
Apache CouchDB is an open-source document-oriented NoSQL database, implemented in Erlang. CouchDB uses multiple formats and protocols to store, transfer, and process its data. It uses JSON to store data, JavaScript as its query language using MapReduce, and HTTP for an API. CouchDB was first released in 2005 and later became an Apache Software Foundation project in 2008. Unlike a relational database, a CouchDB database does not store data and relationships in tables. Instead, each database is a collection of independent documents. Each document maintains its own data and self-contained schema. An application may access multiple databases, such as one stored on a user's mobile phone and another on a server. Document metadata contains revision information, making it possible to merge any differences that may have occurred while the databases were disconnected. CouchDB implements a form of multiversion concurrency control (MVCC) so it does not lock the database file during writ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache Software Foundation
The Apache Software Foundation ( ; ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open-source software projects. The ASF was formed from a group of developers of the Apache HTTP Server, and incorporated on March 25, 1999. it includes approximately 1000 members. The Apache Software Foundation is a decentralized open source community of developers. The software they produce is distributed under the terms of the Apache License, a permissive open-source license for free and open-source software (FOSS). The Apache projects are characterized by a collaborative, consensus-based development process and an open and pragmatic software license, which is to say that it allows developers, who receive the software freely, to redistribute it under non-free terms. Each project is managed by a self-selected team of technical experts who are active contributors to the project. The ASF is a meritocracy, implying tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lotus Notes
HCL Notes (formerly Lotus Notes then IBM Notes) is a proprietary collaborative software platform for Unix ( AIX), IBM i, Windows, Linux, and macOS, sold by HCLTech. The client application is called Notes while the server component is branded HCL Domino. HCL Notes provides business collaboration functions, such as email, calendars, to-do lists, contact management, discussion forums, file sharing, websites, instant messaging, blogs, document libraries, user directories, and custom applications. It can also be used with other HCL Domino applications and databases. IBM Notes 9 Social Edition removed integration with the office software package IBM Lotus Symphony, which had been integrated with the Lotus Notes client in versions 8.x. Lotus Development Corporation originally developed "Lotus Notes" in 1989. IBM bought Lotus in 1995 and it became known as the Lotus Development division of IBM. On December 6, 2018, IBM announced that it was selling a number of software products to H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CERN
The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Geneva, on the France–Switzerland border. It comprises #Member states and budget, 24 member states. Israel, admitted in 2013, is the only full member geographically out of Europe. CERN is an official United Nations General Assembly observers#Intergovernmental organizations, United Nations General Assembly observer. The acronym CERN is also used to refer to the laboratory; in 2023, it had 2,666 scientific, technical, and administrative staff members, and hosted about 12,370 users from institutions in more than 80 countries. In 2016, CERN generated 49 Byte#Multiple-byte units, petabytes of data. CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research – consequently, numer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Create, Read, Update And Delete
In computer programming, create, read, update, and delete (CRUD) are the four basic operations (actions) of persistent storage. CRUD is also sometimes used to describe user interface conventions that facilitate viewing, searching, and changing information using computer-based forms and reports. History The term ''C.R.U.D'' was likely first popularized in 1983 by James Martin in his book ''Managing the data-base environment''. Conceptual Data can be put in a ''location/area'' of a storage mechanism. * The fundamental feature of a storage location is that its ''content'' is both ''readable'' and ''updatable''. * Before a storage location can be read or updated it needs to be ''created''; that is allocated and initialized with content. * At some later point, the storage location may need to be ''destructed''; that is finalized and deallocated. Together these four operations make up the basic operations of storage management known as CRUD: ''Create'', ''Read'', ''Update'' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertext Transfer Protocol
HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser. Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP version, named 0.9. That version was subsequently developed, eventually becoming the public 1.0. Development of early HTTP Requests for Comments (RFCs) started a few years later in a coordinated effort by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), with work later moving to the IETF. HTTP/1 was finalized and fully documented (as version 1.0) in 1996. It evolved ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Map (higher-order Function)
In many programming languages, map is a higher-order function that applies a given function to each element of a collection, e.g. a list or set, returning the results in a collection of the same type. It is often called ''apply-to-all'' when considered in functional form. The concept of a map is not limited to lists: it works for sequential containers, tree-like containers, or even abstract containers such as futures and promises. Examples: mapping a list Suppose there is list of integers , 2, 3, 4, 5/code> and would like to calculate the square of each integer. To do this, first define a function to square a single number (shown here in Haskell): square x = x * x Afterwards, call: >>> map square , 2, 3, 4, 5 which yields , 4, 9, 16, 25/code>, demonstrating that map has gone through the entire list and applied the function square to each element. Visual example Below, there is view of each step of the mapping process for a list of integers X = , 5, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associative Array
In computer science, an associative array, key-value store, map, symbol table, or dictionary is an abstract data type that stores a collection of (key, value) pairs, such that each possible key appears at most once in the collection. In mathematical terms, an associative array is a function with ''finite'' domain. It supports 'lookup', 'remove', and 'insert' operations. The dictionary problem is the classic problem of designing efficient data structures that implement associative arrays. The two major solutions to the dictionary problem are hash tables and search trees..Dietzfelbinger, M., Karlin, A., Mehlhorn, K., Meyer auf der Heide, F., Rohnert, H., and Tarjan, R. E. 1994"Dynamic Perfect Hashing: Upper and Lower Bounds". SIAM J. Comput. 23, 4 (Aug. 1994), 738-761. http://portal.acm.org/citation.cfm?id=182370 It is sometimes also possible to solve the problem using directly addressed arrays, binary search trees, or other more specialized structures. Many programmin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Array Data Structure
In computer science, an array is a data structure consisting of a collection of ''elements'' (value (computer science), values or variable (programming), variables), of same memory size, each identified by at least one ''array index'' or ''key'', a collection of which may be a tuple, known as an index tuple. An array is stored such that the position (memory address) of each element can be computed from its index tuple by a mathematical formula. The simplest type of data structure is a linear array, also called a one-dimensional array. For example, an array of ten 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as ten Word (data type), words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index ''i'' has the address 2000 + (''i'' × 4). The memory address of the first element of an array is called first address, foundation address, or base address. Because the mathematical conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-Version Concurrency Control
Multiversion concurrency control (MCC or MVCC), is a non-locking concurrency control method commonly used by database management systems to provide concurrent access to the database and in programming languages to implement transactional memory. Description Without concurrency control, if someone is reading from a database at the same time as someone else is writing to it, it is possible that the reader will see a half-written or inconsistent piece of data. For instance, when making a wire transfer between two bank accounts if a reader reads the balance at the bank when the money has been withdrawn from the original account and before it was deposited in the destination account, it would seem that money has disappeared from the bank. Isolation is the property that provides guarantees in the concurrent accesses to data. Isolation is implemented by means of a concurrency control protocol. The simplest way is to make all readers wait until the writer is done, which is known as a read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloudant
Cloudant is an IBM software product, which is primarily delivered as a cloud-based service. Cloudant is a non-relational, distributed database service of the same name. Cloudant is based on the Apache-backed CouchDB project and the open source BigCouch project. Cloudant's service provides integrated data management, search, and analytics engine designed for web applications. Cloudant scales databases on the CouchDB framework and provides hosting, administrative tools, analytics and commercial support for CouchDB and BigCouch. Cloudant's distributed CouchDB service is used the same way as standalone CouchDB, with the added advantage of data being redundantly distributed over multiple machines. Cloudant was acquired by IBM from the start-up company of the same name. The acquisition was announced on February 24, 2014, The acquisition was completed on March 4 of that year. By March 31, 2018, Cloudant Shared Plan will be retired and migrated to IBM Cloud. History Cloudant was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BigCouch
BigCouch is an open-source, highly available, fault-tolerant, clustered & API-compliant version of Apache CouchDB, which was maintained by Cloudant. On January 5, 2012, Cloudant announced they would contribute the BigCouch horizontal scaling framework into the CouchDB project. The merge was completed in July 2013. Cloudant announced in June 2015 that they were no longer supporting BigCouch. BigCouch allows users to create clusters of CouchDBs that are distributed over an arbitrary number of servers. While it appears to the end-user as one CouchDB instance, it is in fact one or more nodes in an elastic cluster, acting in concert to store and retrieve documents, index and serve views, and serve CouchApps. Clusters behave according to concepts outlined in Amazon's Dynamo paper, namely that each node can accept requests, data is placed on partitions based on a consistent hashing algorithm, and quorum protocols are for read/write operations. It relies on Erlang and the Open Telecom Pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
