DBMS Functions (cont'd.)
•Data storage management
–DBMS creates and manages complex structures required for data storage
–Also stores related data entry forms, screen definitions, report definitions, etc.
–Performance tuning: activities that make the database perform more efficiently
–DBMS stores the database in multiple physical data files
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Database Systems, 10th Edition
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Database Systems, 10th Edition
DBMS Functions (cont'd.)
•Data transformation and presentation
–DBMS transforms data entered to conform to required data structures
–DBMS transforms physically retrieved data to conform to user’s logical expectations
•Security management
–DBMS creates a security system that enforces user security and data privacy
–Security rules determine which users can access the database, which items can be accessed, etc.
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Database Systems, 10th Edition
DBMS Functions (cont'd.)
•Multiuser access control
–DBMS uses sophisticated algorithms to ensure concurrent access does not affect integrity
•Backup and recovery management
–DBMS provides backup and data recovery to ensure data safety and integrity
–Recovery management deals with recovery of database after a failure
•Critical to preserving database’s integrity
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Database Systems, 10th Edition
DBMS Functions (cont'd.)
•Data integrity management
–DBMS promotes and enforces integrity rules
•Minimizes redundancy
•Maximizes consistency
–Data relationships stored in data dictionary used to enforce data integrity
–Integrity is especially important in transaction-oriented database systems
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Database Systems, 10th Edition
DBMS Functions (cont'd.)
•Database access languages and application programming interfaces
–DBMS provides access through a query language
–Query language is a nonprocedural language
–Structured Query Language (SQL) is the de facto query language
•Standard supported by majority of DBMS vendors
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Database Systems, 10th Edition
DBMS Functions (cont'd.)
•Database communication interfaces
–Current DBMSs accept end-user requests via multiple different network environments
–Communications accomplished in several ways:
•End users generate answers to queries by filling in screen forms through Web browser
•DBMS automatically publishes predefined reports on a Web site
•DBMS connects to third-party systems to distribute information via e-mail
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Database Systems, 10th Edition
Managing the Database System:
A Shift in Focus
•Database system provides a framework in which strict procedures and standards enforced
–Role of human changes from programming to managing organization’s resources
•Database system enables more sophisticated use of the data
•Data structures created within the database and their relationships determine effectiveness
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Database Systems, 10th Edition
Managing the Database System:
A Shift in Focus (cont'd.)
•Disadvantages of database systems:
–Increased costs
–Management complexity
–Maintaining currency
–Vendor dependence
–Frequent upgrade/replacement cycles
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Database Systems, 10th Edition
Preparing for Your Database Professional Career
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Database Systems, 10th Edition
Summary
•Data are raw facts
•Information is the result of processing data to reveal its meaning
•Accurate, relevant, and timely information is the key to good decision making
•Data are usually stored in a database
•DBMS implements a database and manages its contents
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Database Systems, 10th Edition
Summary (cont'd.)
•Metadata is data about data
•Database design defines the database structure
–Well-designed database facilitates data management and generates valuable information
–Poorly designed database leads to bad decision making and organizational failure
•Databases evolved from manual and computerized file systems
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Database Systems, 10th Edition
Summary (cont'd.)
•In a file system, data stored in independent files
–Each requires its own management program
•Some limitations of file system data management:
–Requires extensive programming
–System administration is complex and difficult
–Changing existing structures is difficult
–Security features are likely inadequate
–Independent files tend to contain redundant data
•Structural and data dependency problems
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Database Systems, 10th Edition