Vertical Fragmentation: – Every single site might not need every columns or attributes of a relation or tables, which would specify the need for a dissimilar type of fragmentation. Vertical fragmentation divides a table or relation “vertically” by means of columns or attributes. A vertical fragment of an attributes or relation keeps only sure columns or attributes of the relation...

Distributed Databases with Client Server Architectures Part – 2 Benefits plus Drawbacks of Distributed Databases The benefits of distributed database are as follows:- • Matches distributed organizational prototype • Upgraded independence as well as local independence • Upgraded accessibility • Upgraded trustworthiness • Upgraded performance • Economical • Segmental development The drawbacks of the distributed database are as follows:- Disadvantages...

Introduction In this article the Distributed Databases (DDBs), Distributed Database Management Systems (DDBMSs), will be discussed along with by what means the Client Server (CS) architecture is castoff as a platform for database application improvement. The Distributed Databases (DDB) technology developed as a blend of two (2) technologies: (1) Database technology, and (2) Network and Data communication technology. The network...

Database Recovery Methods Part – 8 Shadow Paging This recovery system does not need the use of a log in a single user setting. In a multi user setting, a log may be desired for the concurrency control technique. Shadow paging considers the database to be made up of a number of static size disk pages (or disk blocks) like,...

Database Recovery Methods Part – 7 Recovery Methods Based On Instant Update In these methods, at the time when a transaction executes an update command, the database can be updated “instantly,” without any necessity to wait for the transaction to reach its commit point. In these methods, however, an update process should be logged in the log (on disk) before...

Database Recovery Methods Part – 6 Postponed Update with Simultaneous Execution in a Multi User Setting For multi user systems with concurrency control, the recovery procedure might be a bit more difficult, depending on the protocols castoff for concurrency control. In a lot of circumstances, the concurrency control as well as recovery processes are interconnected. In overall, the greater the...

Database Recovery Methods Part – 5 Recovery Methods Based On Delayed Update The notion behind delayed update a method are to delayed or postpone any definite updates to the database until and unless the transaction finishes its implementation effectively as well as reaches its commit point. At the time of transaction implementation, the updates are logged only in the log...

Check Points in System Log plus Fuzzy Check Points A different form of record in the log is known as check point. A check point record is written into the log from time to time at the point when the system writes out to the database on disk every Database Management System (DBMS) buffers which have been altered. As a...

Write – Ahead Logging, Steal or No-Steal, Force or No-Force At the time of using in-place updating, it is essential to make use of log for recovering the data. In this circumstance, the data recovery mechanism should confirm that the before image (BFIM) of the data object is logged in the suitable log entry as well as the log record...

Buffering of Disk Blocks The recovery procedure is frequently carefully tangled with operating system (OS) functions in specific, the buffering as well as caching of disk pages in main memory. Naturally, one (1) or more (N) disk pages which include the information items to be modified are cached into main memory buffers and then updated in memory prior to start...