||A ColumnDefinitionException is thrown if the settings of a
database column are incompatible with the data type of the object field
to which it is mapped.
||A DuplicateDatastoreFieldException is thrown if an attempt is made to
add a column to a table with a name already in-use by an existing column.
||A IncompatibleQueryElementTypeException is thrown if a variable used
in a query is detected to have an type incompatible with the element type of
the collection to which it is being applied.
||A TooManyForeignKeysException is thrown when trying to add a foreign
key to a table and the table already has the maximum allowed number of
||A TooManyIndicesException is thrown when trying to add an index
to a table and the table already has the maximum allowed number of indices.