Oracle International Corporation

Qingyun Xie

Siva Ravada

Zhihai Zhang

Weisheng Xu

Fengting Chen

A method, system, and computer program product for implementing a multi-column/multi-row constraint. Lock techniques prevent access collisions even when two or more concurrently running software applications are attempting to insert rows into the same relational database table (subject to the same multi-column/multi-row constraints). The method commences by receiving (e.g., from a first process) a first row to be inserted into a relational database table where the row comprises at least two constrained columns corresponding to the multi-column/multi-row constraint, then receiving (e.g., from a second process) a second row to be inserted into the same table. Using column locks, the method recognizes the potential for conflicting row insertions, and manages locks to prevent conflicting access grants to the two constrained columns of the existing database table. The evaluation of the multi-column/multi-row constraint is performed over the first row to be inserted and a row or rows of the relational database table.

Implementing a multi-column/multi-row constraint in a relational database table

Systems, methods, and other embodiments associated with generating a mosaic image using a virtual grid are described. In one embodiment, a method includes analyzing, by a processor of an apparatus, a boundary of a requested image to determine source images that collectively form an area that includes the requested image. The method also includes generating, by the processor, a virtual grid from coordinates of the source images by identifying edges of the source images from the coordinates to define rows and columns of the virtual grid within the boundary. The rows and columns of the virtual grid define virtual tiles in the virtual grid.

Image mosaicking using a virtual grid

In one embodiment of the present invention, in a database management system, a system for handling geographic raster data comprises a first data table including a plurality of GeoRaster objects, each GeoRaster object including a spatial extent geometry and associated metadata, the spatial extent geometry identifying a footprint of a geographic raster data object and associated with at least one block of raster data, a second data table including a plurality of raster objects, each raster object associated with one block of raster data of a GeoRaster object and including information indicating a spatial extent of the block of raster data and information relating to the block of raster data, a first spatial index built on the first data table based on the spatial extent geometry of each of the plurality of GeoRaster objects, the first spatial index operable to retrieve a GeoRaster object from the first data table based on a relative spatial location of the GeoRaster object, and a primary key index built on the second data table based on the information relating to the block of raster data, the index operable to retrieve a raster object from the second data table based on the information relating to the block of raster data associated with the retrieved raster object.

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Bedford, NH, United States of America

Qingyun Xie