Kontakt
Ako nakupovať
Doručenie
Nákupný poradca
Query Processing in Database Systems
Angličtina
249 b
30 dní na vrátenie tovaru
Zákazníci tiež kúpili
/
Pevná
10.93
€
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.
Informácie o knihe
Angličtina
Kategórie
Darujte túto knihu ešte dnes
Je to jednoduché
1 Pridajte knihu do košíka a vyberte možnosť doručiť ako darček 2 Obratom Vám zašleme poukaz 3 Knihu zašleme na adresu obdarovanéhoMohlo by vás tiež zaujímať
/
Brožovaná
12.85
€
/
Brožovaná
12.35
€
/
Brožovaná
13.26
€
Ahoj! Som Libroamiko, tvoj knižný radca.
Ako ti môžem pomôcť?