DBMS: Change Data Capture (Definitions)

"As changes are made to a production data source, change data capture reads the source database log. This information can be used to prepare a batch to update the data warehouse, or it can update the data warehouse on a transaction-by-transaction basis. With SQL Server 7.0, transactional replication is an example of change data capture." (Microsoft Corporation, "Microsoft SQL Server 7.0 Data Warehouse Training Kit", 2000)

"The process of capturing changes made to a production data source. Change data capture is typically performed by reading the log file of the Database Management System of the source database. Change data capture consolidates units of work, ensures data is synchronized with the original source, and reduces data volume in a Data Warehousing environment." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"The process of capturing changes made to a production data source; typically used in data warehousing environments." (Craig S Mullins, "Database Administration", 2012)

"Change data capture (CDC) is a set of software design patterns used to determine (and track) the data that has changed so that action can be taken using the changed data. CDC often uses the database transaction log to populate the deltas, although it can also query the database directly." (Piethein Strengholt, "Data Management at Scale", 2020)

"CDC is the process of capturing changes that were made in the source systems and applying these changes throughout the enterprise for both decision support systems such as information warehouse and operational data stores as well as other downstream consuming applications." (Saumya Chaki, "Enterprise Information Management in Practice", 2015)

"An automated approach for ensuring that data changes are synchronized across an enterprise by replicating data changes from a source system to other systems." (Jonathan Ferrar et al, "The Power of People", 2017)

DBMS: Redundancy (Definitions)

"A general term that refers to the capability of an organization to recover from critical database. Redundancy generally involves having more than one source for data, which could be as simple as a backup." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"A system that has been set up so that failure at one point does not cause failure of the entire system." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"Storing more than one occurrence of the data." (Ralph Kimball & Margy Ross, "The Data Warehouse Toolkit" 2nd Ed., 2002)

"the practice of storing more than one occurrence of data. In the case where data can be updated, redundancy poses serious problems. In the case where data is not updated, redundancy is often a valuable and necessary design technique." (William H Inmon, "Building the Data Warehouse", 2005)

"The storage of multiple copies of identical instances of a thing (database, table, record, or value)." (Sharon Allen & Evan Terry, "Beginning Relational Data Modeling" 2nd Ed., 2005)

"Here, the provision of information beyond necessity." (Martin J Eppler, "Managing Information Quality" 2nd Ed., 2006)

"The storage of multiple copies of logically identical data. Physically, the data may or may not be identical across systems, and it is not known which is most current or accurate." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"The assurance of availability by providing duplicate systems or alternative processes." (Mark Rhodes-Ousley, "Information Security: The Complete Reference" 2nd Ed., 2013)

"Surplus capability, which is maintained to improve the reliability of a system." (Manish Agrawal, "Information Security and IT Risk Management", 2014)

"Process of providing alternative resources in order to continue the execution despite any component failures." (Hamid R Arabnia et al, "Application of Big Data for National Security", 2015)

"Multiple occurrence of the same information in different places." (IQBBA, "Standard glossary of terms used in Software Engineering", 2011)

DBMS: Data Replication (Definitions)

 "Duplication of table schema and data or stored procedure definitions and calls from a source database to a destination database, usually on separate servers." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A process that copies and distributes data and database objects from one database to another and then synchronizes information between databases for consistency." (Anthony Sequeira & Brian Alderman, "The SQL Server 2000 Book", 2003)

"The duplication of I/O from one set of disks to another similar set, on a file level." (Tom Petrocelli, "Data Protection and Information Lifecycle Management", 2005)

"A set of technologies for copying and distributing data and database objects from one database to another and then synchronizing between databases to maintain consistency." (Thomas Moore, "MCTS 70-431: Implementing and Maintaining Microsoft SQL Server 2005", 2006)

"This is a process that copies data from one database to another." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"Process of copying data and database objects from one data source to another across a network. This is done to synchronize two databases or to maintain a remote copy of a database." (Sara Morganand & Tobias Thernstrom , "MCITP Self-Paced Training Kit : Designing and Optimizing Data Access by Using Microsoft SQL Server 2005 - Exam 70-442", 2007)

"A process whereby information is published from a database server and sent to one or more subscribers. Data may be transferred proactively by the publisher or requested by the subscribers. See also publishand- subscribe." (Robert D Schneider & Darril Gibson, "Microsoft SQL Server 2008 All-in-One Desk Reference For Dummies", 2008)

"A group of technologies within SQL Server 2005 that are used to copy and distribute data and database objects from one database to another. Data is then regularly synchronized to maintain consistency. Replication uses a publishing metaphor with Publishers (data source), Distributors (process responsible for replicating the data and/or objects), and Subscribers (data target)." (Darril Gibson, "MCITP SQL Server 2005 Database Developer All-in-One Exam Guide", 2008)

"A feature allowing multiple database servers to share the same data, thereby ensuring redundancy and facilitating load balancing." (MongoDb, "Glossary", 2008)

"A process whereby information is published from a database server and sent to one or more subscribers. Data may be transferred proactively by the publisher or requested by the subscribers." (Robert D. Schneider and Darril Gibson, "Microsoft SQL Server 2008 All-In-One Desk Reference For Dummies", 2008)

"A set of techniques and technologies to make and then maintain a copy of data from a source database. Different approaches support different synchronization and performance requirements." (Allen Dreibelbis et al, "Enterprise Master Data Management", 2008)

"The process of storing data in multiple databases while ensuring that it remains consistent. For example, one database might contain a master copy of the data and other satellite databases might hold read-only copies to let clerks view data quickly without impacting the main database." (Rod Stephens, "Beginning Database Design Solutions", 2008)

"Carrying out an identical transaction on two copies of the data in sequence." (David G Hill, "Data Protection: Governance, Risk Management, and Compliance", 2009)

"A method for creating copies of the database, either in real time or in a deferred mode." (Paulraj Ponniah, "Data Warehousing Fundamentals for IT Professionals", 2010)

"The storage of duplicated database fragments at multiple sites on a DDBMS. Duplication of the fragments is transparent to the end user. Used to provide fault tolerance and performance enhancements." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)

"The copying of data from a data source to one or more target environments based on rules." (Craig S Mullins, "Database Administration", 2012)

"The process of copying content and/or configuration settings from one location, generally a server node, to another. Replication is done to ensure synchronization or fault tolerance." (Microsoft, "SQL Server 2012 Glossary", 2012)

"The process of maintaining a defined set of data in more than one location. Replication involves copying designated changes for one location (a source) to another (a target) and synchronizing the data in both locations." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)

IT: Redundant Array of Independent Disks/RAID (Definitions)

"Installation of several disk drives to a system. Some drives contain mirrored information so data is not lost. RAID disk drives can be replaced quickly in cases of disk failure. This technology is good for Web and database servers, so that no information is lost and the information is always available." (Patrick Dalton, "Microsoft SQL Server Black Book", 1997)

"Sometimes referred to as redundant array of inexpensive disks, a system that uses multiple disk drives (an array) to provide performance and reliability. There are six levels describing RAID arrays, 0 through 5. Each level uses a different algorithm to implement fault tolerance." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A disk system that comprises multiple disk drives (an array) to provide higher performance, reliability, storage capacity, and lower cost. Fault-tolerant arrays are categorized in six RAID levels: 0 through 5. Each level uses a different algorithm to implement fault tolerance." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"A specific fault-tolerant disk array system design strategy that takes into account issues of cost benefit, reliability, and performance. It can be implemented at a hardware or a software level; each provides a different profile of cost, reliability, and performance. Depending on the person defining RAID, the word independent may be substituted with inexpensive." (Allan Hirt et al, "Microsoft SQL Server 2000 High Availability", 2004)

"A bunch of small, cheap disks. A RAID array is a group of disks used together as a single unit logical disk. RAID arrays can help with storage capacity, recoverability and performance, using what are called mirroring and striping. Mirroring creates duplicate copies of all physical data. Striping breaks data into many small pieces, where those small pieces can be accessed in parallel." (Gavin Powell, "Beginning Database Design", 2006)

"A schema for using groups of disks to increase performance, protect data, or both." (Tom Petrocelli, "Data Protection and Information Lifecycle Management", 2005)

"This is a grouping, or array, of hard disks that appear as a single, logical drive to the operating system." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"RAID is an acronym for Redundant Array of Independent Disks. RAID is a collection of disks that operates as a single disk." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"A RAID array uses multiple physical disks to simulate one logical, larger disk, often with protection from disk failure. (The I can also stand for Independent, and the D can also stand for Drives.) " (Victor Isakov et al, "MCITP Administrator: Microsoft SQL Server 2005 Optimization and Maintenance (70-444) Study Guide", 2007)

"Using more disks than is necessary for the actual data itself, as a buffer against failure of one (or possibly more) disks." (David G Hill, "Data Protection: Governance, Risk Management, and Compliance", 2009)

"A category of disk drives that employ two or more drives in combination for fault tolerance and performance." (Martin Oberhofer et al, "The Art of Enterprise Information Architecture", 2010)

"A system of disk storage where data is distributed across several drives for faster access and improved fault tolerance." (Paulraj Ponniah, "Data Warehousing Fundamentals for IT Professionals", 2010)

"A technology for configuring a logical data storage device across multiple physical devices to improve performance, availability or both. The primary goal is fault tolerance as in most configurations data can be recovered after a device failure and in some cases, without interruption." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"An acronym that means Redundant Array of Independent Disks. RAID is used to provide balance between performance and fault tolerance. RAID systems use multiple disks to create virtual disks (storage volumes) formed by several individual disks. RAID systems provide performance improvement and fault tolerance." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)

"A category of disk drives that employ two or more drives in combination to deliver fault tolerance and improved performance." (Craig S Mullins, "Database Administration", 2012)

"A multi-disk storage system that optimizes performance, data safety, or both, depending on the type." (Faithe Wempen, "Computing Fundamentals: Introduction to Computers", 2015)