76. Oracle Spatial/Locator

76.1. Introduction

It allows access to both Oracle Spatial tables as Oracle Locator (both from version 9i) if they have a column of geometries stored as SDO GEOMETRY:type SDO geometries stored GEOMETRY.

The "Oracle Spatial / Locator Support" extension is installed using the "Addonn Manager."

76.2. Metadata

The driver lists only tables with their geographic metadata in the USER_SDO_GEOM_METADATA view.

Since it has the metadata for each table, the interface makes use of them and automatically provides the geometry columns. As row identifier uses the ROWID, which is an unique descriptor for each row usied by Oracle internally and ensures correct identification.

76.3. Data type

      Data are supported in 2D and 3D of the following types:

  • Point and multipoint

  • Line and multi-line

  • Polygon and multipolygon

  • Collection

    Layers with LRS (Linear Referencing System) format are not supported.

76.4. Coodinate systems

Oracle has its own cataloging system of coordinate systems and reference. There is a relationship of equivalences between the Oracle system and the EPSG system that is included in the driver as a DBF file.

Transformations between coordinate systems are performed by gvSIG.

76.5. Reading geometries

The driver constantly runs geometric queries (ie, calculates at each moment what geometries intersect with the current gvSIG view) for which it is imperative that exists in the database a spatial index associated with the column in question. If there is no index, an error window is displayed and is not possible to add such a table or view to the gvSIG View.
On the other hand, the driver needs to set an unique identifier for the records of the table or view, which is not possible for certain types of views. In case of this problem, the driver will detect it and an error message is also displayed, making it impossible to load that view of the database in gvSIG.

76.6. Dumping gvSIG layer to Oracle

When you export a layer to an Oracle database, at the end, the process will ask whether you want to include in the table the current coordinate system of the View.