|
Natural Key
A natural key (also known as business key or domain key) is a type of unique key in a database formed of attributes that exist and are used in the external world outside the database (i.e. in the business domain or domain of discourse). In the relational model of data, a natural key is a superkey and is therefore a functional determinant for all attributes in a relation. A natural key serves two complementary purposes: * It provides a means of unique identification for data * It imposes a rule, specifically a uniqueness constraint, to ensure that data remains unique within an information system The uniqueness constraint assures uniqueness of data within a certain technical context (e.g. a set of values in a table, file or relation variable) by rejecting input of any data that would otherwise violate the constraint. This means that the user can rely on a guaranteed correspondence between facts identified by key values recorded in a system and the external domain of discourse (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unique Key
In relational database management systems, a unique key is a candidate key. All the candidate keys of a relation can uniquely identify the records of the relation, but only one of them is used as the primary key of the relation. The remaining candidate keys are called unique keys because they can uniquely identify a record in a relation. Unique keys can consist of multiple columns. Unique keys are also called alternate keys. Unique keys are an alternative to the primary key of the relation. In SQL, the unique keys have a UNIQUE constraint assigned to them in order to prevent duplicates (a duplicate entry is not valid in a unique column). Alternate keys may be used like the primary key when doing a single-table select or when filtering in a ''where'' clause, but are not typically used to join multiple tables. Summary Keys provide the means for database users and application software to identify, access and update information in a database table. ''There may be several keys in any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ralph Kimball
Ralph Kimball (born July 18, 1944) is an author on the subject of data warehousing and business intelligence. He is one of the original architects of data warehousing and is known for long-term convictions that data warehouses must be designed to be understandable and fast. His bottom-up methodology, also known as dimensional modeling or the Kimball methodology, is one of the two main data warehousing methodologies alongside Bill Inmon. He is the principal author of the best-selling books ''The Data Warehouse Toolkit'' (1996), ''The Data Warehouse Lifecycle Toolkit'' (1998), ''The Data Warehouse ETL Toolkit'' (2004) and ''The Kimball Group Reader'' (2015), published by Wiley and Sons. Career After receiving a Ph.D. in 1973 from Stanford University in electrical engineering (specializing in man-machine systems), Ralph joined the Xerox Palo Alto Research Center (PARC). At PARC Ralph was a principal designer of the Xerox Star Workstation, the first commercial product to use mice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knowledge Management
Knowledge management (KM) is the set of procedures for producing, disseminating, utilizing, and overseeing an organization's knowledge and data. It alludes to a multidisciplinary strategy that maximizes knowledge utilization to accomplish organizational goals. Courses in business administration, information systems, management, libraries, and information science are all part of knowledge management, a discipline that has been around since 1991. Information and media, computer science, public health, and public policy are some of the other disciplines that may contribute to KM research. Numerous academic institutions provide master's degrees specifically focused on knowledge management. As a component of their IT, human resource management, or business strategy departments, many large corporations, government agencies, and nonprofit organizations have resources devoted to internal knowledge management initiatives. These organizations receive KM guidance from a number of consulting ... [...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] |
Social Security Number
In the United States, a Social Security number (SSN) is a nine-digit number issued to United States nationality law, U.S. citizens, Permanent residence (United States), permanent residents, and temporary (working) residents under section 205(c)(2) of the Social Security Act, codified as . The number is issued to an individual by the Social Security Administration, an Independent agencies of the United States government, independent agency of the United States government. Although the original purpose for the number was for the Social Security Administration to track individuals, the Social Security number has become a ''de facto'' national identification number for Taxation in the United States, taxation and other purposes. A Social Security number may be obtained by applying on Form SS-5, Application for a Social Security Number Card. History Social Security numbers were first issued by the Social Security Administration in November 1936 as part of the New Deal Social Securit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Business Rule
A business rule defines or constrains some aspect of a business. It may be expressed to specify an action to be taken when certain conditions are true or may be phrased so it can only resolve to either true or false. Business rules are intended to assert business structure or to control or influence the behavior of the business. Business rules describe the operations, definitions and constraints that apply to an organization. Business rules can apply to people, processes, corporate behavior and computing systems in an organization, and are put in place to help the organization achieve its goals. For example, a business rule might state that ''no credit check is to be performed on return customers''. Other examples of business rules include requiring a rental agent to disallow a rental tenant if their credit rating is too low, or requiring company agents to use a list of preferred suppliers and supply schedules. While a business rule may be informal or even unwritten, documenting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Key
In the relational model of databases, a primary key is a designated attribute (column) that can reliably identify and distinguish between each individual record in a table. The database creator can choose an existing unique attribute or combination of attributes from the table (a natural key) to act as its primary key, or create a new attribute containing a unique ID that exists solely for this purpose (a surrogate key). Examples of natural keys that could be suitable primary keys include data that is already by definition unique to all items in the table such as a national identification number attribute for person records, or the combination of a very precise timestamp attribute with a very precise location attribute for event records. More formally, a primary key is a specific choice of a minimal set of attributes that uniquely specify a tuple ( row) in a relation (table). A primary key is a choice of a candidate key (a minimal superkey); any other candidate key is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Quality
Data quality refers to the state of qualitative or quantitative pieces of information. There are many definitions of data quality, but data is generally considered high quality if it is "fit for tsintended uses in operations, decision making and planning". Data is deemed of high quality if it correctly represents the real-world construct to which it refers. Apart from these definitions, as the number of data sources increases, the question of internal data consistency becomes significant, regardless of fitness for use for any particular external purpose. People's views on data quality can often be in disagreement, even when discussing the same set of data used for the same purpose. When this is the case, businesses may adopt recognised international standards for data quality (See #International Standards for Data Quality below). Data governance can also be used to form agreed upon definitions and standards, including international standards, for data quality. In such cases, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surrogate Key
A surrogate key (or synthetic key, pseudokey, entity identifier, factless key, or technical key) in a database is a unique identifier for either an ''entity'' in the modeled world or an ''object'' in the database. The surrogate key is ''not'' derived from application data, unlike a ''natural'' (or ''business'') key. Definition There are at least two definitions of a surrogate: ; Surrogate (1) – Hall, Owlett and Todd (1976): A surrogate represents an ''entity'' in the outside world. The surrogate is internally generated by the system but is nevertheless visible to the user or application. ; Surrogate (2) – Wieringa and De Jonge (1991): A surrogate represents an ''object'' in the database itself. The surrogate is internally generated by the system and is invisible to the user or application. The ''Surrogate (1)'' definition relates to a data model rather than a storage model and is used throughout this article. See Date (1998). An important distinction between a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Version Of The Truth
In computerized business management, single version of the truth (SVOT), is a technical concept describing the data warehousing ideal of having either a single centralised database, or at least a distributed synchronised database, which stores all of an organisation's data in a consistent and non-redundant form. This contrasts with the related concept of single source of truth (SSOT), which refers to a data storage principle to always source a particular piece of information from one place. Applied to message sequencing In some systems and in the context of message processing systems (often real-time systems), this term also refers to the goal of establishing a single agreed sequence of messages within a database formed by a particular but arbitrary sequencing of records. The key concept is that data combined in a certain sequence is a "truth" which may be analyzed and processed giving particular results, and that although the sequence is arbitrary (and thus another correct bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an application associated with the database. Before digital storage and retrieval of data have become widespread, index cards were used for data storage in a wide range of applications and environments: in the home to record and store recipes, shopping lists, contact information and other organizational data; in business to record presentation notes, project research and notes, and contact information; in schools as flash c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information System
An information system (IS) is a formal, sociotechnical, organizational system designed to collect, process, Information Processing and Management, store, and information distribution, distribute information. From a sociotechnical perspective, information systems comprise four components: task, people, structure (or roles), and technology. Information systems can be defined as an integration of components for collection, storage and data processing, processing of data, comprising digital products that process data to facilitate decision making and the data being used to provide information and contribute to knowledge. A computer information system is a system, which consists of people and computers that process or interpret information. The term is also sometimes used to simply refer to a computer system with software installed. "Information systems" is also an academic field of study about systems with a specific reference to information and the complementary networks of computer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
