| Record | an aggregation of values of data organized by their relation to a common key. |
| Recovery | the restoration of the database to an original position or condition, often after major damage to the physical medium. |
| Redundancy | the practice of storing more than one occurrence of data. |
| Referential Integrity | the facility of a DBMS to ensure the validity of a predefined relationship. |
| Refresh | Refreshing a warehouse consists in propagating updates on source data to correspondingly update the base data and derived data stored in the warehouse. Two sets of issues to consider; when to refresh and how to refresh. Refresh policy is set by warehouse administrator, depends on user needs and traffic and may be different for different sources. |
| Replication | The physical copying of data from one database to another. |
| Reporting | The process of translating data to presentation formats via a pre-defined or ad-hoc queries. |
| ROLAP | Relational OLAP. Data warehouses that are implemented on standard or extended relational DBMSs,called Relational OLAP(ROLAP)servers.These servers assume that data is stored in relational databases. |
| Roll up | to increase or acquire by successive accumulations |
| Rolling Summary | a form of storing archival data where the most recent data has the lowest level of details stored ande the older datra has higher levels of details stored. |
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