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DUAL Table
The DUAL table is a special one-row, one-column table present by default in Oracle and other database installations. In Oracle, the table has a single VARCHAR2(1) column called DUMMY that has a value of 'X'. It is suitable for use in selecting a pseudo column such as SYSDATE or USER. Example use Oracle's SQL syntax requires the FROM clause but some queries don't require any tables - DUAL can be used in these cases. SELECT 1+1 FROM dual; SELECT 1 FROM dual; SELECT USER FROM dual; SELECT SYSDATE FROM dual; SELECT * FROM dual; History Charles Weiss explains why he created DUAL: I created the DUAL table as an underlying object in the Oracle Data Dictionary. It was never meant to be seen itself, but instead used inside a view that was expected to be queried. The idea was that you could do a JOIN to the DUAL table and create two rows in the result for every one row in your table. Then, by using GROUP BY, the resulting join could be summarized to show the amount of storage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Table (database)
A table is a collection of related data held in a table format within a database. It consists of columns and rows. In relational databases, and flat file databases, a ''table'' is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows, the 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"; although there is the difference in that a table is usually a multiset (bag) of rows where a relation is a set and does not allow duplicates. Besides the actual data rows, tables generally have associated with them some metadata, such as constraints on the table or on the values within particular columns. The data in a table does not have to be physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft SQL Server
Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet). Microsoft markets at least a dozen different editions of Microsoft SQL Server, aimed at different audiences and for workloads ranging from small single-machine applications to large Internet-facing applications with many concurrent users. History The history of Microsoft SQL Server begins with the first Microsoft SQL Server product—SQL Server 1.0, a 16-bit server for the OS/2 operating system in 1989—and extends to the current day. Its name is entirely descriptive, it being ''server'' software that responds to queries in the '' SQL'' language. Milestones * MS SQL Server for OS/2 began as a project to port Sybase SQL Server onto O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertica
Vertica Systems is an analytic database management software company. Vertica was founded in 2005 by the database researcher Michael Stonebraker, with Andrew Palmer as the founding CEO. Ralph Breslauer and Christopher P. Lynch served as later CEOs. Lynch joined as chairman and CEO in 2010 and was responsible for Vertica's acquisition by Hewlett Packard in March 2011. The acquisition expanded the HP Software portfolio for enterprise companies and the public sector group. As part of the merger of Micro Focus and the Software division of Hewlett Packard Enterprise, Vertica joined Micro Focus in September, 2017. Products The column-oriented Vertica Analytics Platform was designed to manage large, fast-growing volumes of data and with fast query performance for data warehouses and other query-intensive applications. The product claims to greatly improve query performance over traditional relational database systems, and to provide high availability and exabyte scalability on co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teradata
Teradata Corporation is an American software company that provides cloud database and analytics-related software, products, and services. The company was formed in 1979 in Brentwood, California, as a collaboration between researchers at Caltech and Citibank's advanced technology group. Overview Teradata is an enterprise software company that develops and sells database analytics software. The company provides three main services: business analytics, cloud products, and consulting. It operates in North and Latin America, Europe, the Middle East, Africa and Asia. Teradata is headquartered in San Diego, California, and has additional major U.S. locations in Atlanta and San Francisco, where its data center research and development is housed. It is publicly traded on the New York Stock Exchange (NYSE) under the stock symbol TDC. Steve McMillan has served as the company's president and chief executive officer since 2020. The company reported $1.836 billion in revenue, with a net incom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAP HANA
SAP HANA (HochleistungsANalyseAnwendung or High-performance ANalytic Application) is an in-memory, column-oriented, relational database management system developed and marketed by SAP SE. Its primary function as the software running a database server is to store and retrieve data as requested by the applications. In addition, it performs advanced analytics (predictive analytics, spatial data processing, text analytics, text search, streaming analytics, graph data processing) and includes extract, transform, load (ETL) capabilities as well as an application server. History During the early development of SAP HANA, a number of technologies were developed or acquired by SAP SE. These included TREX search engine ( in-memory column-oriented search engine), P*TIME (in-memory online transaction processing (OLTP) Platform acquired by SAP in 2005), and MaxDB with its in-memory liveCache engine. The first major demonstration of the platform was in 2008: teams from SAP SE, the Hasso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SQLite
SQLite (, ) is a 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. History D. Richard Hipp designed SQLite in the spring of 2000 while working for General Dynamics on contract with the United States Navy. Hipp was designing software used for a damage-control system aboard guided-missile destroyers, which originally used HP-UX with an IBM Informix database back-end. SQLite began as a Tcl extension. In August 2000, versio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowflake Inc
Snowflake Inc. is a cloud computing–based data cloud company based in Bozeman, Montana. It was founded in July 2012 and was publicly launched in October 2014 after two years in stealth mode. The firm offers a cloud-based data storage and analytics service, generally termed "data-as-a-service". It allows corporate users to store and analyze data using cloud-based hardware and software. Snowflake services main features are separation of storage and compute, on-the-fly scalable compute, data sharing, data cloning, and third-party tools support in order to handle the demanding needs of growing enterprises. It runs on Amazon S3 since 2014, on Microsoft Azure since 2018 and on the Google Cloud Platform since 2019. The company was ranked first on the ''Forbes'' Cloud 100 in 2019. The company's initial public offering raised $3.4 billion, one of the largest software IPOs in history. History Snowflake Inc. was founded in July 2012 in San Mateo, California by three data warehousing exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PostgreSQL
PostgreSQL (, ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the Ingres database developed at the University of California, Berkeley. In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. After a review in 2007, the development team decided to keep the name PostgreSQL and the alias Postgres. PostgreSQL features transactions with Atomicity, Consistency, Isolation, Durability (ACID) properties, automatically updatable views, materialized views, triggers, foreign keys, and stored procedures. It is designed to handle a range of workloads, from single machines to data warehouses or Web services with many concurrent users. It is the default database for macOS Server and is also available for Windows, Linux, FreeBSD, and OpenBSD. History PostgreSQL evolved from the Ingres proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MySQL
MySQL () is an 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 relational database organizes data into one or more data tables in which data may be related to each other; these relations help structure the data. SQL is a language programmers use to create, modify and extract data from the relational database, as well as control user access to the database. In addition to relational databases and SQL, an RDBMS like MySQL works with an operating system to implement a relational database in a computer's storage system, manages users, allows for network access and facilitates testing database integrity and creation of backups. MySQL is free and open-source software under the terms of the GNU General Public License, and is also available under a variety of proprietary licenses. MySQL was owned and sponsored by the Swedish com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft Access
Microsoft Access is a database management system (DBMS) from Microsoft that combines the relational Access Database Engine (ACE) with a graphical user interface and software-development tools (not to be confused with the old Microsoft Access which was a telecommunication program that provided terminal emulation and interfaces for ease of use in accessing online services such as Dow Jones, Compuserve and electronic mailbox in the 1980s). It is a member of the Microsoft 365 suite of applications, included in the Professional and higher editions or sold separately. Microsoft Access stores data in its own format based on the Access Database Engine (formerly Jet Database Engine). It can also import or link directly to data stored in other applications and databases. Software developers, data architects and power users can use Microsoft Access to develop application software. Like other Microsoft Office applications, Access is supported by Visual Basic for Applications (VBA), an obj ... [...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 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-prem, on-cloud, or as a hybrid cloud installation. It may be run on third party servers as well as on Oracle hardware (Exadata on-prem, on Oracle Cloud or at Cloud at Customer). 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. SDL developed the original version of the Oracle software. The name ''Oracle'' comes from the code-name of a CIA-funded project Ellison had worked on while formerly employed by Ampex. Releases and versions Oracle products follow a custom r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Informix
IBM Informix is a product family within IBM's Information Management division that is centered on several relational database management system (RDBMS) offerings. The Informix products were originally developed by Informix Corporation, whose Informix Software subsidiary was acquired by IBM in 2001. In April 2017, IBM delegated active development and support to HCL Technologies for 15 years while keeping part of the marketing responsibilities. The current version of Informix is 14.10 and forms the basis of several product editions with variation in capacity and functionality. The Informix database has been used in many high transaction rate OLTP applications in the retail, finance, energy and utilities, manufacturing and transportation sectors. More recently the server has been enhanced to improve its support for data warehouse workloads. Through extensions, Informix supports data types that are not a part of the SQL standard. Key products As of 2020, the current version of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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