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Client-Server and Distributed Data Bases - Coggle Diagram
Client-Server and Distributed Data Bases
Client-Server
Advantages
scalability
vertical
capacity on server-side
horizontal
capacity on client-side
interoperability
use software and data
systems to exchange
flexibility
easy maintaining
easy adapting
server
performs requests
communicates results
client
requests to server
Architecture
Multiple-Tier Architecture
additional layers of servers
improve performance
finer processing division
Web Services Architecture
interaction between
service requestor
searches for service
uses service
service registry
repository
service provider
owns service
platform offering service
Advantages
communicate new services in standard formats
find existing services
deploy services faster
reduce electronic business's cost
Three-Tier Architecture
improve performance
add middleware server
transaction-processing monitor
more simultaneous connections
message-oriented middleware
more flexibility in messages
add application server
Two-Tier Architecture
Advantages
easy to implement
Disadvantages
difficult maintenance
rely on proprietary software
for systems with
moderate clients' number
stable requirements
Distributed Data
Advantages
improved performance
lower communication costs
data control
available data
Architecture
Schema Architectures
allocation schema
fragment's location
fragmentation schema
fragment's definition
fragment
horizontal subset
mixed fragment
vertical subset
allocated to one/multiple site
Distributed Query Processing
local optimization
global optimization
data movement
site selection decisions
local and global optimization
Site
local data managers
complete DBMS' features
heterogeneous
homogeneous
locally controlled computer
unique network address
distributed data manager
controls access to remote data
coordinates concurrency control
optimizes query
controls recovery across sites
uses global dictionary
coordinate local managers
Global requests
combine data and transactions (update data at sites)