Coordinate system transformation techniques
As we have seen in the first section of this chapter, it is very common to do coordinate system transformations as part of the data loading process. Many of the external data loading tools provide these transformations, but sometimes it is convenient and more efficient to do these transformations in the database. Oracle Spatial provides two distinct methods for doing coordinate system transformations. The SDO_CS.TRANSFORM function works on one row at a time to transform a geometry, while the SDO_CS.TRANSFORM_LAYER function works on a whole table of data and transforms all the geometries in a column of the table. Both methods support different use cases: the transform function is mainly used in dynamic query situations, while the TRANSFORM_LAYER function is mainly used in bulk update or bulk loading situations. As we are describing data loading techniques in this chapter, we will describe how both these methods can be used in bulk data loading situations...