diff --git a/sql/upgrades/157.sql b/sql/upgrades/157.sql
index cadd4c24..6245e5dd 100644
--- a/sql/upgrades/157.sql
+++ b/sql/upgrades/157.sql
@@ -1,63 +1,68 @@
 -- SWH DB schema upgrade
 -- from_version: 156
 -- to_version: 157
 -- description: Add extrinsic artifact metadata
 
 -- latest schema version
 insert into dbversion(version, release, description)
       values(157, now(), 'Work In Progress');
 
 create domain swhid as text check (value ~ '^swh:[0-9]+:.*');
 
-alter table origin_metadata
-  rename to object_metadata;
+-- Extrinsic metadata on a DAG objects and origins.
+create table object_metadata
+(
+  type           text          not null,
+  id             text          not null,
 
+  -- metadata source
+  authority_id   bigint        not null,
+  fetcher_id     bigint        not null,
+  discovery_date timestamptz   not null,
 
--- Use the origin URL as identifier, instead of the origin id
-alter table object_metadata
-  add column type text;
-comment on column object_metadata.type is 'the type of object (content/directory/revision/release/snapshot/origin) the metadata is on';
-
-alter table object_metadata
-  add column origin_url text;
-
-update object_metadata
-  set
-    type = 'origin',
-    origin_url = origin.url
-  from origin
-  where object_metadata.origin_id = origin.id;
+  -- metadata itself
+  format         text          not null,
+  metadata       bytea         not null,
 
-alter table object_metadata
-  alter column type set not null;
-alter table object_metadata
-  alter column origin_url set not null;
-
-alter table object_metadata
-  drop column id;
-alter table object_metadata
-  drop column origin_id;
+  -- context
+  origin         text,
+  visit          bigint,
+  snapshot       swhid,
+  release        swhid,
+  revision       swhid,
+  path           bytea,
+  directory      swhid
+);
 
-alter table object_metadata
-  rename column origin_url to id;
+comment on table object_metadata is 'keeps all metadata found concerning an object';
+comment on column object_metadata.type is 'the type of object (content/directory/revision/release/snapshot/origin) the metadata is on';
 comment on column object_metadata.id is 'the SWHID or origin URL for which the metadata was found';
+comment on column object_metadata.discovery_date is 'the date of retrieval';
+comment on column object_metadata.authority_id is 'the metadata provider: github, openhub, deposit, etc.';
+comment on column object_metadata.fetcher_id is 'the tool used for extracting metadata: loaders, crawlers, etc.';
+comment on column object_metadata.format is 'name of the format of metadata, used by readers to interpret it.';
+comment on column object_metadata.metadata is 'original metadata in opaque format';
+
+-- migrate data from origin_metadata
+insert into object_metadata(type, id, authority_id, fetcher_id, discovery_date, format, metadata,
+                            origin)
+select 'origin', id, authority_id, fetcher_id, discovery_date, format, metadata,
+       (select url from origin o where o.id = om.origin_id)
+from origin_metadata om;
 
 create unique index object_metadata_content_authority_date_fetcher
   on object_metadata(id, authority_id, discovery_date, fetcher_id);
 
-
--- Add context columns
-alter table object_metadata
-  add column origin text;
 alter table object_metadata
-  add column visit bigint;
-alter table object_metadata
-  add column snapshot swhid;
-alter table object_metadata
-  add column release swhid;
+  add constraint object_metadata_authority_fkey
+  foreign key (authority_id) references metadata_authority(id) not valid;
+
 alter table object_metadata
-  add column revision swhid;
+  validate constraint object_metadata_authority_fkey;
+
 alter table object_metadata
-  add column path bytea;
+  add constraint object_metadata_fetcher_fkey
+  foreign key (fetcher_id) references metadata_fetcher(id) not valid;
+
 alter table object_metadata
-  add column directory swhid;
+  validate constraint object_metadata_fetcher_fkey;