User's Guide and Reference

Creating spatial indexes

This chapter explains how to use the Control Center to create an index for your spatial data.

After you populate spatial columns with your data, you are ready to create a spatial index. Typical indexing structures, such as a B-tree, perform linear, one-dimensional sorts on table data. Table data that has been enabled for spatial operations is not stored as a single entry, but is two-dimensional. For example, spatial geometries such as a polygon consists of several coordinate values in one spatial column or layer. Because a B-tree index cannot handle spatial data types, DB2 Spatial Extender created a proprietary indexing technology known as a grid index. The grid index is based on the B-tree index, which was enhanced to handle two-dimensional data and perform indexing on spatial columns. The grid index supports three layers and is designed to provide good performance over a wide range of objects, sizes, and distributions of data. For more information about spatial indexes, see Spatial indexes.

To find out what authorization is required for creating a spatial index, see Authorization.


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