澳洲代写assignment：数据管理
澳洲代写assignment：数据管理
历史或演变：
1. 1950年代以来档案制度的历史：
数据在创建停止存在的进程之后被存储。
2.二十世纪六十年代以来的网络层次：包括：
Concurrency
数据恢复
快速访问数据。
复杂的数据结构。
3. 1970-80年的数据关系阶段：
提供更可靠的数据。
减少冗余
数据更加灵活。
多个视图的选项也可用。
4. 20世纪90年代的ODBMS阶段：
更好的模拟设施可用。
不同类型的数据可用。
存在不同类型的关系，如聚合和专业化。
数据库和编程以单一语言提供。
优秀表格的版本可用。
其他面向对象的优点（重用，继承等）
早期的信息系统：
由于计算机容量有限，二十世纪六十年代末和七十年代初信息系统的发展受到限制。与目前的标准相比，硬件相对昂贵，而且相当有限。对于单个芯片程序来说，结合用户界面来实现信息系统。与数据管理有关的逻辑数据处理和操作可以在单个文件中和单个机器上在该时间点执行。编程和调试成本以及投入实施的时间和金钱是值得关注的问题。在信息系统的总成本中，最大的百分比用于生产目的。随着商业环境的变化，改变系统的压力也相当大。另一个问题是，随着复杂度的增加，在设计阶段引入错误检测元件变得越来越重要。最常见的设计问题是多余的。
澳洲代写assignment：数据管理
History or Evolution:
1. History of system of files since 1950’s:
Data is stored after creating the process for which existence is ceased.
2. Hierarchy of networks since 1960’s: It includes:
Concurrency
Data recovery
Faster access of data.
Complicated data Structures.
3. Relational stage of data from 1970-80:
It offers more reliability of data.
Less redundancy
Data is more flexible.
Options of multiple views are also available.
4. ODBMS stage of 1990’s:
Better simulation facility is available.
Different types of data are available.
Different kinds of relationships existed such as aggregation and specialization.
Databases and programming were available in single language.
Versioning of superior forms was available.
Other OO advantages (reuse, inheritance etc.)
Early information systems:
To development of the information systems in the late 1960’s and early 1970’s was limited due to the limited capacity of the computers. Hardware was relatively expensive in comparison to the present standards and was quite limited. For a single chip program the implementation of the information system in combination with the user interface. Logical data processing and operations related to data management were executable in a single file and on a single machine at that point of time. The cost of programming and debugging cost and the time and money invested in its implementation was the question of concern. Out of the total cost incurred in the information system the biggest percentage was used for production purposes. As the business environment changes there arises considerable pressure for changing the system. Another problem is that with the increase in the complexity it becomes more and more important in the design phase to introduce error detection element. The most common design problems were redundant.
