title: Non spatial indexes in Oracle
body: <p>I'm trying to create a non-spatial index on two columns, one of which is a geometry column (SDO_GEOMETRY). It appears from the documentation that it is possible but I'm unable to create one.</p>
  
  <p>An excerpt from the Oracle documentation:</p>
  
  <blockquote>
    <p>For each spatial column in a non-SPATIAL index except POINT columns, a
    column prefix length must be specified. (This is the same requirement
    as for indexed BLOB columns.) The prefix length is given in bytes.</p>
  </blockquote>
  
  <p>Here's the query I'm trying to execute to create the index:</p>
  
  <pre><code>create index multiple_column_index on TestDB (ID, SHAPE) tablespace test;
  </code></pre>
  
  <p>The SHAPE column is the geometry column here. The error I'm receiving is:</p>
  
  <pre><code>SQL Error: ORA-02327: cannot create index on expression with datatype ADT
  02327. 00000 -  "cannot create index on expression with datatype %s"
  *Cause:    An attempt was made to create an index on a non-indexable
         expression.
  *Action:   Change the column datatype or do not create the index on an
         expression whose datatype is one of  VARRAY, nested table, object,
         LOB, or  REF.
  </code></pre>
  
  <p>I've not applied the column prefix here as I couldn't find any documentation that explains its usage.</p>