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Change Vector
In an Oracle database, a change vector consists of a single change to a single data block. A change vector is the smallest unit of change recorded in a redo log In the Oracle RDBMS environment, redo logs comprise files in a proprietary format which log a history of all changes made to the database. Each redo log file consists of redo records. A redo record, also called a redo entry, holds a group of cha ... (in its turn, a redo log comprises files in a proprietary format which logs a history of all changes made to the database). Source for further reading Change Vector Oracle software Transaction processing {{database-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Database
Oracle Database (commonly referred to as Oracle DBMS, Oracle Autonomous Database, or simply as Oracle) is a proprietary multi-model database management system produced and marketed by Oracle Corporation. It is a database commonly used for running online transaction processing (OLTP), data warehousing (DW) and mixed (OLTP & DW) database workloads. Oracle Database is available by several service providers on-premises, on-cloud, or as a hybrid cloud installation. It may be run on third party servers as well as on Oracle hardware ( Exadata on-premises, on Oracle Cloud or at Cloud at Customer). Oracle Database uses SQL for database updating and retrieval. History Larry Ellison and his two friends and former co-workers, Bob Miner and Ed Oates, started a consultancy called Software Development Laboratories (SDL) in 1977, later Oracle Corporation. SDL developed the original version of the Oracle software. The name ''Oracle'' comes from the code-name of a CIA-funded proj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Block
In computing (specifically data transmission and data storage), a block, sometimes called a physical record, is a sequence of bytes or bits, usually containing some whole number of records, having a fixed length; a ''block size''. Data thus structured are said to be ''blocked''. The process of putting data into blocks is called ''blocking'', while ''deblocking'' is the process of extracting data from blocks. Blocked data is normally stored in a data buffer, and read or written a whole block at a time. Blocking reduces the overhead and speeds up the handling of the data stream. For some devices, such as magnetic tape and CKD disk devices, blocking reduces the amount of external storage required for the data. Blocking is almost universally employed when storing data to 9-track magnetic tape, NAND flash memory, and rotating media such as floppy disks, hard disks, and optical discs. Most file systems are based on a block device, which is a level of abstraction for the hardware ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redo Log
In the Oracle RDBMS environment, redo logs comprise files in a proprietary format which log a history of all changes made to the database. Each redo log file consists of redo records. A redo record, also called a redo entry, holds a group of change vectors, each of which describes or represents a change made to a single block in the database. For example, if a user UPDATEs a salary-value in a table containing employee-related data, the DBMS generates a redo record containing change-vectors that describe changes to the data segment block for the table. And if the user then COMMITs the update, Oracle generates another redo record and assigns the change a "system change number" (SCN). Whenever something changes in a datafile, Oracle records the change in the redo log. The name ''redo log'' indicates its purpose: If the database crashes, the RDBMS can redo (re-process) all changes on datafiles which will take the database data back to the state it was when the last redo record was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Software
An oracle is a person or thing considered to provide insight, wise counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. If done through occultic means, it is a form of divination. Description The word ''oracle'' comes from the Latin verb ''ōrāre'', "to speak" and properly refers to the priest or priestess uttering the prediction. In extended use, ''oracle'' may also refer to the ''site of the oracle'', and the oracular utterances themselves, are called ''khrēsmoí'' (χρησμοί) in Greek. Oracles were thought to be portals through which the gods spoke directly to people. In this sense, they were different from seers (''manteis'', μάντεις) who interpreted signs sent by the gods through bird signs, animal entrails, and other various methods.Flower, Michael Attyah. ''The Seer in Ancient Greece.'' Berkeley: University of California Press, 2008. The most important oracles of Greek antiquity were Pythia (priestess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
