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Client-Server and Distributed Databases - Coggle Diagram
Client-Server and Distributed Databases
Distributed data
Distributed Database Architecture
Distributed Query Processing
Local (intrasite) optimization
Gloabl (intersite) optimixation
Schema Architecture
Fragments
Vertical subset
Horizontal subset
Mixed fragment
Goabal request
Support gloabl requests that use data storages at more than one autonomus site
Can lead to lower communication costs and improved performance
Offers a number of avantages related to datacontrol, communication costs and performance
Site
Distributed data manager
Local data managers
Homogeneous
Heterogeneous
Each server with the access to the distributed databases
Client
Is a program that makes requests to a server
Server
Peroforms reuqest and communcates reslts to the clients
Client-server advantages
Flexibility refers to the ease of maintaining and adapting a system
Scalability refers to the ability to add and remove capacity is small units
Interoperability refers to the ability of two or more systems to exchange and use software add data
Client-server Database Architecures
Two-Tier Architecture
Positive side: the two-tier architecture is the simplest to implement due to the number of good comercial development environments
Negative side: spftware maintenance can be difficult because PC clients a mix of presentation, validation, and business logic code
Three-tier Architecture
Adds another server layer to improve performance
Middleware server
Transaction-processing monitor
May support more simultaneous connections than message-oriented middleware
Message-oriented middleware
Provides more flexibility in the kinds of messages supported
Application server
Can be distributed between the databse server and PC clients
Multiple-tier Architecture
Supports additional layer of servers to improve performance and provide flexible division or processing
Web Services Architecture
Supports interaction between a service provider, service requestor, and service registry