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Data Management
Detailed Information About the JGOFS Distributed Database Management System (DDMS)
Data Objects
Data Objects package together a program (the
translator or method) and data. User programs never
look at the data directly; rather, they communicate with the data
object.
- Data Objects communicate with a common protocol
- --> All data objects present the same
appearance to outside (described here)
- --> Programs can work with any data in the system (Example)
- Data Objects handle
- Projection (subsetting by variable name)
- Selection (subsetting by variable values)
- --> Can minimize transmission of data
- --> Individual objects may have other functions
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