   unmapped_object_id    INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
   type                  ENUM('xref', 'cDNA', 'Marker', 'probe2transcript') NOT NULL,
   analysis_id           INT(10) UNSIGNED NOT NULL,
-  external_db_id        INT(10) UNSIGNED NOT NULL,
+  external_db_id        INT(10) UNSIGNED,
   identifier            VARCHAR(255) NOT NULL,
   unmapped_reason_id    SMALLINT(5) UNSIGNED NOT NULL,
   query_score           DOUBLE,


INSERT INTO meta (meta_key, meta_value) VALUES ('patch', 'patch_42_43_a.sql|unmapped_object.parent');
INSERT INTO meta (meta_key, meta_value) VALUES ('patch', 'patch_42_43_b.sql|unmapped_object_probe2transcript');

################################################################################
#

   display_label              VARCHAR(128) NOT NULL,
   version                    VARCHAR(10) DEFAULT '0' NOT NULL,
   description                VARCHAR(255),
   info_type                  ENUM('PROJECTION', 'MISC', 'DEPENDENT', 'DIRECT', 'SEQUENCE_MATCH', 'INFERRED_PAIR', 'PROBE', 'UNMAPPED'),
   info_text                  VARCHAR(255),

   PRIMARY KEY (xref_id),
