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Physical Data Model
A physical data model (or database design) is a representation of a data design as implemented, or intended to be implemented, in a database management system. In the Project lifecycle, lifecycle of a project it typically derives from a logical data model, though it may be reverse-engineered from a given database implementation. A complete physical data model will include all the database artifacts required to create Relational database, relationships between tables or to achieve performance goals, such as index (database), indexes, constraint definitions, Associative entity, linking tables, Partition (database), partitioned tables or Data cluster, clusters. Analysts can usually use a physical data model to calculate storage estimates; it may include specific storage allocation details for a given database system. seven main databases dominate the commercial marketplace: Informix Dynamic Server, Informix, Oracle Database, Oracle, PostgreSQL, Postgres, Microsoft SQL Server, SQL S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Data Model Options
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Sybase
Sybase, Inc. was an enterprise software and services company. The company produced software relating to relational databases, with facilities located in California and Massachusetts. Sybase was acquired by SAP in 2010; SAP ceased using the Sybase name in 2014. History *1984: Robert Epstein—formerly with Ingres—and Mark Hoffman leave Britton-Lee. They, Jane Doughty, and Tom Haggin start Sybase (initially trading as ''Systemware'') in Epstein's home in Berkeley, California. Their first commercial location is half of an office suite at 2107 Dwight Way in Berkeley. They set out to create a relational database management system (RDBMS) that will organize information and make it available to computers within a network. *March 1986: Systemware enters into talks with Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hierarchical Database Model
A hierarchical database model is a data model in which the data is organized into a tree-like structure. The data are stored as records which is a collection of one or more fields. Each field contains a single value, and the collection of fields in a record defines its type. One type of field is the link, which connects a given record to associated records. Using links, records link to other records, and to other records, forming a tree. An example is a "customer" record that has links to that customer's "orders", which in turn link to "line_items". The hierarchical database model mandates that each child record has only one parent, whereas each parent record can have zero or more child records. The network model extends the hierarchical by allowing multiple parents and children. In order to retrieve data from these databases, the whole tree needs to be traversed starting from the root node. Both models were well suited to data that was normally stored on tape drives, which had to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Schema
A logical data model or logical schema is a data model of a specific problem domain expressed independently of a particular database management product or storage technology ( physical data model) but in terms of data structures such as relational tables and columns, object-oriented classes, or XML tags. This is as opposed to a conceptual data model, which describes the semantics of an organization without reference to technology. Overview Logical data models represent the abstract structure of a domain of information. They are often diagrammatic in nature and are most typically used in business processes that seek to capture things of importance to an organization and how they relate to one another. Once validated and approved, the logical data model can become the basis of a physical data model and form the design of a database. Logical data models should be based on the structures identified in a preceding conceptual data model, since this describes the semantics of the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conceptual Schema
A conceptual schema or conceptual data model is a high-level description of informational needs underlying the design of a database. It typically includes only the core concepts and the main relationships among them. This is a high-level model with insufficient detail to build a complete, functional database. It describes the structure of the whole database for a group of users. The conceptual model is also known as the data model that can be used to describe the conceptual schema when a database system is implemented. It hides the internal details of physical storage and targets the description of entities, datatypes, relationships and constraints. Overview A conceptual schema is a map of concepts and their relationships used for databases. This describes the semantics of an organization and represents a series of assertions about its nature. Specifically, it describes the things of significance to an organization (''entity classes''), about which it is inclined to collec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Schema Approach
The three-schema approach, or three-schema concept, in software engineering is an approach to building information systems and systems information management that originated in the 1970s. It proposes three different views in systems development, with conceptual modelling being considered the key to achieving data integration. Overview The three-schema approach provides for three types of schemas with schema techniques based on formal language descriptions: * External schema for user views * Conceptual schema integrates external schemata * Internal schema that defines physical storage structures At the center, the conceptual schema defines the ontology of the concepts as the users think of them and talk about them. The physical schema according to Sowa (2004) "describes the internal formats of the data stored in the database, and the external schema defines the view of the data presented to the application programs." The framework attempted to permit multiple data models to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANSI-SPARC Architecture
The ANSI-SPARC Architecture (American National Standards Institute, Standards Planning And Requirements Committee), is an abstract design standard for a database management system (DBMS), first proposed in 1975.ANSI/X3/SPARC Study Group on Data Base Management Systems: (1975), ''Interim Report. FDT'', ACM SIGMOD bulletin. Volume 7, No. 2 The ANSI-SPARC model however, never became a formal standard. No mainstream DBMS systems are fully based on it (they tend not to exhibit full physical independence or to prevent direct user access to the conceptual level), but the idea of Data independence, logical data independence is widely adopted. Three-level architecture The objective of the three-level architecture is to separate the user's view: *It allows independent customized user views: Each user should be able to access the same data, but have a different customized view of the data. These should be independent: changes to one view should not affect others. *It hides the physical st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Storage
Computer data storage or digital data storage is a technology consisting of computer components and Data storage, recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage's Analytical Engine and Percy Ludgate's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the Von Neumann archite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 formally. A datum is an individual value in a collection of data. Data are usually organized into structures such as tables that provide additional context and meaning, and may themselves be used as data in larger structures. Data may be used as variables in a computational process. Data may represent abstract ideas or concrete measurements. Data are commonly used in scientific research, economics, and virtually every other form of human organizational activity. Examples of data sets include price indices (such as the consumer price index), unemployment rates, literacy rates, and census data. In this context, data represent the raw facts and figures from which useful information can be extracted. Data are collected using technique ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Management
Data management comprises all disciplines related to handling data as a valuable resource, it is the practice of managing an organization's data so it can be analyzed for decision making. Concept The concept of data management emerged alongside the evolution of computing technology. In the 1950s, as computers became more prevalent, organizations began to grapple with the challenge of organizing and storing data efficiently. Early methods relied on punch cards and manual sorting, which were labor-intensive and prone to errors. The introduction of database management systems in the 1970s marked a significant milestone, enabling structured storage and retrieval of data. By the 1980s, relational database models revolutionized data management, emphasizing the importance of data as an asset and fostering a data-centric mindset in business. This era also saw the rise of data governance practices, which prioritized the organization and regulation of data to ensure quality and complian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Administrator
A database administrator (DBA) manages computer databases. The role may include capacity planning, installation, configuration, database design, migration, performance monitoring, security, troubleshooting, as well as backup and data recovery. Skills Required skills for database administrators include knowledge of SQL, database queries, database theory, database design, specific databases, such as Oracle, Microsoft SQL Server, or MySQL, storage technologies, distributed computing architectures, operating systems, routine maintenance, recovery, and replication/failover. Certification Training for DBAs with accompanying certifications is widely available, offered by database vendors and third parties. Offerings include: * IBM Certified Advanced Database Administrator – DB2 10.1 for Linux, Unix and Windows * IBM Certified Database Administrator – DB2 10.1 for Linux, Unix, and Windows * Oracle Database 12c Administrator Certified Professional * Oracle MySQL 5.6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft Windows
Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sectors of the computing industry – Windows (unqualified) for a consumer or corporate workstation, Windows Server for a Server (computing), server and Windows IoT for an embedded system. Windows is sold as either a consumer retail product or licensed to Original equipment manufacturer, third-party hardware manufacturers who sell products Software bundles, bundled with Windows. The first version of Windows, Windows 1.0, was released on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs). The name "Windows" is a reference to the windowing system in GUIs. The 1990 release of Windows 3.0 catapulted its market success and led to various other product families ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
