Query Processing in Database Systems
W. Kim · D.S. Reiner · Don Batory
2012-12 · Springer Science & Business Media
El. knyga
366
Puslapiai
reportĮvertinimai ir apžvalgos nepatvirtinti. Sužinokite daugiau
Apie šią el. knygą
This book is an anthology of the results of research and development in database query processing during the past decade. The relational model of data provided tremendous impetus for research into query processing. Since a relational query does not specify access paths to the stored data, the database management system (DBMS) must provide an intelligent query-processing subsystem which will evaluate a number of potentially efficient strategies for processing the query and select the one that optimizes a given performance measure. The degree of sophistication of this subsystem, often called the optimizer, critically affects the performance of the DBMS. Research into query processing thus started has taken off in several directions during the past decade. The emergence of research into distributed databases has enormously complicated the tasks of the optimizer. In a distributed environment, the database may be partitioned into horizontal or vertical fragments of relations. Replicas of the fragments may be stored in different sites of a network and even migrate to other sites. The measure of performance of a query in a distributed system must include the communication cost between sites. To minimize communication costs for-queries involving multiple relations across multiple sites, optimizers may also have to consider semi-join techniques.
Įvertinti šią el. knygą
Pasidalykite savo nuomone.
Skaitymo informacija
Išmanieji telefonai ir planšetiniai kompiuteriai
Įdiekite „Google Play“ knygų programą, skirtą „Android“ ir „iPad“ / „iPhone“. Ji automatiškai susinchronizuojama su paskyra ir jūs galite skaityti tiek prisijungę, tiek neprisijungę, kad ir kur būtumėte.
Nešiojamieji ir staliniai kompiuteriai
Galite klausyti garsinių knygų, įsigytų sistemoje „Google Play“ naudojant kompiuterio žiniatinklio naršyklę.
El. knygų skaitytuvai ir kiti įrenginiai
Jei norite skaityti el. skaitytuvuose, pvz., „Kobo eReader“, turite atsisiųsti failą ir perkelti jį į įrenginį. Kad perkeltumėte failus į palaikomus el. skaitytuvus, vadovaukitės išsamiomis pagalbos centro instrukcijomis.
