本文探讨了数据库管理中的关键问题，包括数据冗余、数据隐私、数据一致性及依赖性。数据冗余可能导致更新异常，而数据库方法能有效减少冗余。数据隐私方面，文件系统易导致数据泄露，而关系数据库通过创建不同视图来保护隐私。数据一致性是由于错误传播，而使用关系数据库可以避免。数据依赖性方面，文件系统修改数据结构复杂，数据库方法简化了这一过程。最后，数据库支持复杂的搜索和查询操作。
Keywords: data redundancy, data privacy, data consistency, data integrity, data dependency, search & query
- Data redundancy: the same data stored more than once. It's common that there are several copies of files so that the data can be shared to different people. This increases the data redundancy. One of the primary aims of the data base approach is the elimination of data redundancy.
- Data privacy: one problem of file-base approach is lack of data privacy. Data file copies are shared to different people and no control to the access of the data. This leads to data privacy issue. Using relational database, different views can be created for different people. Each one can only see parts of data that is related to his work. This protects data privacy in a much better way.
- Data consistency: since there are copies of data, if there is an error in the original data, each copy will contain the same error. Later if the error needs to be corrected, all the copies have to be updated. Otherwise, the data is inconsistent. This is a different cause of data lacking integrity. Relational database can be used to avoid this.
- Data dependency: Programs can be used to manipulate data. The program code depends on the format of data and the way data is organized if file-based approach is used. If there is a need to change the format of data or append a field to the structure of the data, the program code has to be changed accordingly. Relational database approach can reduce the complexity of and the time to complete such work.
- Search and query: using databases, complex search and query can be carried out with SQL.
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