计算机英语中英对照：数据库的空间组织

Spatial Management of DataBase

　　Spatial data management has been an activearea of research in the database field for two decades，with much of the research being focused on develop-ing data structures for storing and indexing spatialdata. However, no commercial database system pro-vides facilities for directly defining and storing spa-tial data, and forniulating queries based on researchconditions on spatial data. We believe the followingare the relevant issues on which near-term researchshould be focused (in the order of decreasing impor-tance and urgency)．
　　First, relational query optimization techniquesneed to be extended to deal with spatial queries，thatis，queries that contain search conditions on spatialpredicates to be developed.
　　Second, more work needs to be done on experi-mental validation of the relative performance of someof the more promising data structures and indexingstructures proposed thus far, with consideration of amuch broader set of operations than just a few opera-tions that have typically been used in the limited per-formance studies conducted thus far.
　　Third, it is difficult to build into a single data-base system multiple data structures for spatial index-ing, and all spatial operators that are useful for awide variety of spatial applications，as such, it isdesirable to build a database system so that it will beas easy as possible to extend the system with addi-tional data structures and spatial operators．