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Hierarchical And Recursive Queries In SQL
A hierarchical query is a type of SQL query that handles hierarchical model data. They are special cases of more general recursive fixpoint queries, which compute transitive closures. In standard SQL:1999 hierarchical queries are implemented by way of recursive ''common table expressions'' (CTEs). Unlike Oracle's earlier connect-by clause, recursive CTEs were designed with fixpoint semantics from the beginning. Recursive CTEs from the standard were relatively close to the existing implementation in IBM DB2 version 2. Recursive CTEs are also supported by Microsoft SQL Server (since SQL Server 2008 R2), Firebird 2.1, PostgreSQL 8.4+, SQLite 3.8.3+, IBM Informix version 11.50+, CUBRID, MariaDB 10.2+ and MySQL 8.0.1+Tableau has documentationdescribing how CTEs can be used. TIBCO Spotfire does not support CTEs, while Oracle 11g Release 2's implementation lacks fixpoint semantics. Without common table expressions or connected-by clauses it is possible to achieve hierarchical qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Select (SQL)
The SQL SELECT statement returns a result set of records, from one or more tables. A SELECT statement retrieves zero or more rows from one or more database tables or database views. In most applications, SELECT is the most commonly used data manipulation language (DML) command. As SQL is a declarative programming language, SELECT queries specify a result set, but do not specify how to calculate it. The database translates the query into a " query plan" which may vary between executions, database versions and database software. This functionality is called the " query optimizer" as it is responsible for finding the best possible execution plan for the query, within applicable constraints. The SELECT statement has many optional clauses: * SELECT clause is the list of columns or SQL expressions that must be returned by the query. This is approximately the relational algebra projection operation. * AS optionally provides an alias for each column or expression in the SELECT clause ... [...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] |
EnterpriseDB
EnterpriseDB (EDB), a privately held company based in Massachusetts, provides software and services based on the open-source database PostgreSQL (also known as Postgres), and is one of the largest contributors to Postgres. EDB develops and integrates performance, security, and manageability enhancements into Postgres to support enterprise-class workloads. EDB has also developed database compatibility for Oracle to facilitate the migration of workloads from Oracle to EDB Postgres and to support the operation of many Oracle workloads on EDB Postgres. EDB provides a portfolio of databases and tools that extend Postgres for enterprise workloads. This includes fully managed Postgres in the cloud, extreme high availability for Postgres, command line migration tools, Kubernetes Operator and container images, management, monitoring and optimizing of Postgres, enterprise ready Oracle migration tools and browser-based schema migration tools EnterpriseDB was purchased by Great Hill Partn ... [...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] |
Factorial
In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial: \begin n! &= n \times (n-1) \times (n-2) \times (n-3) \times \cdots \times 3 \times 2 \times 1 \\ &= n\times(n-1)!\\ \end For example, 5! = 5\times 4! = 5 \times 4 \times 3 \times 2 \times 1 = 120. The value of 0! is 1, according to the convention for an empty product. Factorials have been discovered in several ancient cultures, notably in Indian mathematics in the canonical works of Jain literature, and by Jewish mystics in the Talmudic book '' Sefer Yetzirah''. The factorial operation is encountered in many areas of mathematics, notably in combinatorics, where its most basic use counts the possible distinct sequences – the permutations – of n distinct objects: there In mathematical analysis, factorials are used in power series for the exponential function an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 individual products' articles for further information. Unless otherwise specified in footnotes, comparisons are based on the stable versions without any add-ons, extensions or external programs. General information Operating system support The operating systems that the RDBMSes can run on. Fundamental features Information about what fundamental RDBMS features are implemented natively. Note (1): Currently only supports read uncommited transaction isolation. Version 1.9 adds serializable isolation and version 2.0 will be fully ACID compliant. Note (2): MariaDB and MySQL provide ACID compliance through the default InnoDB storage engine. Note (3): "For other than InnoDB storage engines, MySQL Server parses and ignores the FOREIGN KEY and REFERENCES syntax in CREATE TABLE statements. The CHECK clause is parsed but ignored by all storage engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H2 (DBMS)
H2 is a relational database management system written in Java. It can be embedded in Java applications or run in client-server mode. The software is available as open source software Mozilla Public License 2.0 or the original Eclipse Public License. History The development of the H2 database engine started in May 2004, and first published in December 2005. The database engine was written by Thomas Mueller. He also developed the Java database engine Hypersonic SQL. In 2001, the Hypersonic SQL project was stopped, and the HSQLDB Group was formed to continue work on the Hypersonic SQL code. The name H2 stands for Hypersonic 2, however H2 Does not share code with Hypersonic SQL or HSQLDB. H2 is built from scratch. Main features Use of SQL A subset of the SQL (Structured Query Language) standard is supported. The main programming APIs are SQL and JDBC, however the database also supports using the PostgreSQL ODBC driver by acting like a PostgreSQL server. Table types It is possible ... [...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] |
Sybase (database)
SAP ASE (Adaptive Server Enterprise), originally known as Sybase SQL Server, and also commonly known as Sybase DB or Sybase ASE, is a relational model database server developed by Sybase Corporation, which later became part of SAP AG. ASE was developed for the Unix operating system, and is also available for Microsoft Windows. In 1988, Sybase, Microsoft and Ashton-Tate began development of a version of SQL Server for OS/2, but Ashton-Tate later left the group and Microsoft went on to port the system to Windows NT. When the agreement expired in 1993, Microsoft purchased a license for the source code and began to sell this product as Microsoft SQL Server. MS SQL Server and Sybase SQL Server share many features and syntax peculiarities. History Bob Epstein left Britton Lee, Inc. to help found Sybase and carried a lot of the ideas from the hardware database with him. Reasoning that standard hardware such as Intel, Motorola and Sun 32 and 64 bit processors running database softwar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BigQuery
BigQuery is a fully managed, serverless data warehouse that enables scalable analysis over petabytes of data. It is a ''Platform as a Service'' (PaaS) that supports querying using ANSI SQL. It also has built-in machine learning capabilities. BigQuery was announced in May 2010 and made generally available in November 2011. Design BigQuery provides external access to Google's Dremel technology, a scalable, interactive ''ad hoc'' query system for analysis of nested data. BigQuery requires all requests to be authenticated, supporting a number of Google-proprietary mechanisms as well as OAuth. Features * Managing data - Create and delete objects such as tables, views, and user defined functions. Import data from Google Storage in formats such as CSV, Parquet, Avro or JSON. * Query - Queries are expressed in a standard SQL dialect and the results are returned in JSON with a maximum reply length of approximately 128 MB, or an unlimited size when large query results are enabled. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSQLDB
HSQLDB (''Hyper SQL Database'') is a relational database management system written in Java. It has a JDBC driver and supports a large subset of SQL-92, SQL:2008, SQL:2011, and SQL:2016 standards. It offers a fast, small (around 1300 kilobytes in version 2.2) database engine which offers both in-memory and disk-based tables. Both embedded and server modes are available. Additionally, it includes tools such as a minimal Web server, command line and GUI management tools (can be run as applets), and a number of demonstration examples. It can run on Java runtimes from version 1.1 upwards, including free Java implementations such as Kaffe. HSQLDB is available under a BSD license. It is used as a database and persistence engine in many open source software projects, such as descendants of OpenOffice.org Base (i.e., Apache OpenOffice Base, LibreOffice Base, etc.), and the Jitsi VoIP and video-conference client since version 2.6. It is also used in commercial products, such as Mathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
