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A database administrator (DBA) manages computer databases. [1] The role may include capacity planning , installation , configuration , database design , migration , performance monitoring, security , troubleshooting , as well as backup and data recovery .
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
It is not a case of “if” but a case of “when” a database suffers a failure, ranging from a simple failure to a full catastrophic failure. The failure may be data corruption, media failure, or user induced errors. In either situation the DBA must have the skills to recover the database to a given point in time to prevent a loss of data.
Formally, a "database" refers to a set of related data accessed through the use of a "database management system" (DBMS), which is an integrated set of computer software that allows users to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data).
These schedules are recoverable. The schedule F is recoverable because T1 commits before T2, that makes the value read by T2 correct. Then T2 can commit itself. In the F2 schedule, if T1 aborted, T2 has to abort because the value of A it read is incorrect. In both cases, the database is left in a consistent state.
MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [6] is an open-source relational database management system (RDBMS). [6] [7] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [1] and "SQL", the acronym for Structured Query Language.
W3Schools is a freemium educational website for learning coding online. [1] [2] Initially released in 1998, it derives its name from the World Wide Web but is not affiliated with the W3 Consortium. [3] [4] [unreliable source] W3Schools offers courses covering many aspects of web development. [5] W3Schools also publishes free HTML templates.
In September 2015, Codecademy, in partnership with Periscope, added a series of courses designed to teach SQL, the predominant programming language for database queries. [21] In October 2015, Codecademy created a new course, a class on Java programming. As of January 2014, the site had over 24 million users who had completed over 100 million ...