advantages, disadvantages of DBMS

Advantages

* Reduced data redundancy
* Reduced updating errors and increased consistency
* Greater data integrity and independence from applications programs
* Improved data access to users through use of host and query languages
* Improved data security
* Reduced data entry, storage, and retrieval costs
* Facilitated development of new applications program

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Disadvantages
* 限制: Database systems are complex, difficult, and time-consuming to design
* Substantial hardware and software start-up costs
* Damage to database affects virtually all applications programs
* Extensive conversion costs in moving form a file-based system to a database system
* Initial training required for all programmers and users
# the need for multiple external databases;
# the need to hire database-related employees;
# high DBMS acquisition costs;
# 限制: a more complex programmer environment;
# 限制: potentially catastrophic program failures;
# a longer running time for individual applications; and,
# highly dependent DBMS operations.