code: public String buildWhere(String field, Object value, String operation) {
  		return CoreSQLUtils.quoteWrap(field) + " "
  				+ (value != null ? operation + " ?" : "IS NULL");
  	}
docs: Build where (or selection) statement for a single field using the
  provided operation
  
  @param field
  field
  @param value
  value
  @param operation
  operation
  @return where clause