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Partition (database)
A partition is a division of a logical database or its constituent elements into distinct independent parts. Database partitioning refers to intentionally breaking a large database into smaller ones for scalability purposes, distinct from network partitions which are a type of network fault between nodes. In a partitioned database, each piece of data belongs to exactly one partition, effectively making each partition a small database of its own. Database partitioning is normally done for manageability, performance or availability reasons, or for load balancing. It is popular in distributed database management systems, where each partition may be spread over multiple nodes, with users at the node performing local transactions on the partition. This increases performance for sites that have regular transactions involving certain views of data, whilst maintaining availability and security. Partitioning enables distribution of datasets across multiple disks and query loads across mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adminer04
Adminer (formerly known as phpMinAdmin) is a tool for managing content in databases. It natively supports MySQL, MariaDB, PostgreSQL, SQLite, MS SQL, Oracle Database, Oracle, Elasticsearch and MongoDB. Adminer is distributed under Apache license (or GNU General Public License#Version 2, GPL v2) in a form of a single PHP file (around 470 KiB in size). Its author is Jakub Vrána who started to develop this tool as a light-weight alternative to phpMyAdmin, in July 2007. Adminer got some attention in 2008 when it made it to the CCA finals at SourceForge. Also, first webhosting providers started to include Adminer as MySQL managing tool into their portfolio of services. In 2012 Adminer got coverage on Linux.com for the second time. The project's priorities, according to its author, are (in this order): safety, user-friendliness, performance, functionality, and size. Features * Users log in specifying the destination server and providing the user name and password (which is stored duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bigtable
Bigtable is a fully managed wide-column and key-value NoSQL database service for large analytical and operational workloads as part of the Google Cloud portfolio. History Bigtable development began in 2004.. It is now used by a number of Google applications, such as Google Analytics, web indexing, MapReduce, which is often used for generating and modifying data stored in Bigtable, Google Maps,. Google Books search, "My Search History", Google Earth, Blogger.com, Google Code hosting, YouTube, and Gmail. Google's reasons for developing its own database include scalability and better control of performance characteristics. Apache HBase and Cassandra are some of the best known open source projects that were modeled after Bigtable. Bigtable offerHBaseanCassandra compatible APIs On May 6, 2015, a public version of Bigtable was made available as a part of Google Cloud under the name Cloud Bigtable. As of April 2024, Bigtable manages over 10 Exabytes of data and serves more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Table (database)
In a database, a table is a collection of related data organized in Table (information), table format; consisting of Column (database), columns and row (database), rows. In relational databases, and flat file databases, a ''table'' is a set of data elements (values) using a model of vertical column (database), columns (identifiable by name) and horizontal row (database), rows, the cell (database), cell being the unit where a row and column intersect. A table has a specified number of columns, but can have any number of rows. Each row is identified by one or more values appearing in a particular column subset. A specific choice of columns which uniquely identify rows is called the primary key. "Table" is another term for relation (database), "relation"; although there is the difference in that a table is usually a multiset (bag) of rows where a relation is a set (computer science), set and does not allow duplicates. Besides the actual data rows, tables generally have associated wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete Uniform Distribution
In probability theory and statistics, the discrete uniform distribution is a symmetric probability distribution wherein each of some finite whole number ''n'' of outcome values are equally likely to be observed. Thus every one of the ''n'' outcome values has equal probability 1/''n''. Intuitively, a discrete uniform distribution is "a known, finite number of outcomes all equally likely to happen." A simple example of the discrete uniform distribution comes from throwing a fair six-sided die. The possible values are 1, 2, 3, 4, 5, 6, and each time the die is thrown the probability of each given value is 1/6. If two dice were thrown and their values added, the possible sums would not have equal probability and so the distribution of sums of two dice rolls is not uniform. Although it is common to consider discrete uniform distributions over a contiguous range of integers, such as in this six-sided die example, one can define discrete uniform distributions over any finite set. Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Function
A hash function is any Function (mathematics), function that can be used to map data (computing), data of arbitrary size to fixed-size values, though there are some hash functions that support variable-length output. The values returned by a hash function are called ''hash values'', ''hash codes'', (''hash/message'') ''digests'', or simply ''hashes''. The values are usually used to index a fixed-size table called a ''hash table''. Use of a hash function to index a hash table is called ''hashing'' or ''scatter-storage addressing''. Hash functions and their associated hash tables are used in data storage and retrieval applications to access data in a small and nearly constant time per retrieval. They require an amount of storage space only fractionally greater than the total space required for the data or records themselves. Hashing is a computationally- and storage-space-efficient form of data access that avoids the non-constant access time of ordered and unordered lists and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consistent Hashing
In computer science, consistent hashing is a special kind of hashing technique such that when a hash table is resized, only n/m keys need to be remapped on average where n is the number of keys and m is the number of slots. In contrast, in most traditional hash tables, a change in the number of array slots causes nearly all keys to be remapped because the mapping between the keys and the slots is defined by a modular operation. Consistent hashing evenly distributes cache keys across shards, even if some of the shards crash or become unavailable. History The term "consistent hashing" was introduced by David Karger ''et al.'' at MIT for use in distributed caching, particularly for the web. This academic paper from 1997 in Symposium on Theory of Computing introduced the term "consistent hashing" as a way of distributing requests among a changing population of web servers. Each slot is then represented by a server in a distributed system or cluster. The addition of a server and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nordic Countries
The Nordic countries (also known as the Nordics or ''Norden''; ) are a geographical and cultural region in Northern Europe, as well as the Arctic Ocean, Arctic and Atlantic Ocean, North Atlantic oceans. It includes the sovereign states of Denmark, Finland, Iceland, Norway and Sweden; the autonomous administrative division, autonomous territories of the Faroe Islands and Greenland; and the autonomous region of Åland. The Nordic countries have much in common in their way of life, History of Scandinavia, history, religion and Nordic model, social and economic model. They have a long history of political unions and other close relations but do not form a singular state or federation today. The Scandinavism, Scandinavist movement sought to unite Denmark, Norway and Sweden into one country in the 19th century. With the dissolution of the union between Norway and Sweden (Norwegian independence), the independence of Finland in the early 20th century and the 1944 Icelandic constitution ... [...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] |
Row (database)
In a relational database, a row or " record" or " tuple", represents a single, implicitly structured data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ... item in a table. A database table can be thought of as consisting of rows and columns. Cory Janssen, Techopedia, retrieved 27 June 2014 Each row in a table represents a set of related data, and every row in the table has the same structure. For example, in a table that represents companies, each row might represent a single company. Columns might represent things like company name, address, etc. In a table that represents ''the association'' of empl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relational Database Management System
A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A Relational Database Management System (RDBMS) is a type of database management system that stores data in a structured format using rows and columns. Many relational database systems are equipped with the option of using SQL (Structured Query Language) for querying and updating the database. History The concept of relational database was defined by E. F. Codd at IBM in 1970. Codd introduced the term ''relational'' in his research paper "A Relational Model of Data for Large Shared Data Banks". In this paper and later papers, he defined what he meant by ''relation''. One well-known definition of what constitutes a relational database system is composed of Codd's 12 rules. However, no commercial implementations of the relational model conform to all of Codd's rules, so the term has gradually come to describe a broader class of database systems, which at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Master-slave Replication
Replication in computing refers to maintaining multiple copies of data, processes, or resources to ensure consistency across redundant components. This fundamental technique spans databases, file systems, and distributed systems, serving to improve availability, fault-tolerance, accessibility, and performance. Through replication, systems can continue operating when components fail (failover), serve requests from geographically distributed locations, and balance load across multiple machines. The challenge lies in maintaining consistency between replicas while managing the fundamental tradeoffs between data consistency, system availability, and network partition tolerance – constraints known as the CAP theorem. Terminology Replication in computing can refer to: * ''Data replication'', where the same data is stored on multiple storage devices * ''Computation replication'', where the same computing task is executed many times. Computational tasks may be: ** ''Replicated in sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
