Author: Li (bfbd@sina.com)
1.1. Demand premise:
Data changes 1 to 2 times a year, the software is expected to have a life cycle 50 years
1.2. Practice:
Oracle Spatial
1.3. Glossary:
Time and space object, snapshot
1.3.1. Time and space object
A geographic goal has been born to the spatial and time range experienced by death and its attribute information. This is an abstract concept that is convenient to handle time and space data, which is equivalent to full information objects in full information models. In order to understand the time and space object, we take two-dimensional substitute as an example. The two-dimensional substitute occupies a certain spatial range in the two-dimensional space, which is characterized by a two-dimensional geometry, that is, its geometric properties. If a time axis is added, it is (x, y, t) coordinate system, and it is considered that any space object has been born and dying, and this two-dimensional object is occupied in the (x, y, t) coordinate system. A certain three-dimensional space. We call the space-time range of the two-dimensional substance from the birth of the time to die. "Time and Space". Similarly, it is also possible to extend the time-space object to a three-dimensional spatial object continuation in time dimension, that is, a four-dimensional object. The attribute information of the time and space object is a two-dimensional table.
1.3.2. Snapshot
A geographic objective occupies the spatial range and its attribute information occupied at a particular time, or: the spatial scope occupied by a short target and its corresponding attribute information. For example, the location of a hotel is drawn on the map, which is a snapshot of the hotel. Because the hotel is born from a certain time, it will die or expand between a certain time, and between birth and demise, may also be relocated or expanded. So just the state of the map is only a state of the hotel at a certain moment, so it is called a snapshot of a snapshot or space-time object at a certain moment on a particular moment. Note that snapshots always correspond to a particular moment, otherwise it will lose the meaning of the snapshot. The property information of the snapshot is a record in the Temporal Temperature Object Property.
1.4. Design direction:
The concept of space data and attribute data in the concept of time and space have enabled queries and analysis of the historical history of the ground object.
The process of processing the historical data is one of the functions of the database module for the processing of printing history data.
1.5. Technical points:
1, Oracle package variable session independence
2, dynamic view technology (view based on functions)
1.6. Graphical solution:
Figure 1-1 图 注 ABC (black body Times New Roman, Xiao 5)
