diff --git a/sql/upgrades/115.sql b/sql/upgrades/115.sql
new file mode 100644
index 00000000..7e35f60f
--- /dev/null
+++ b/sql/upgrades/115.sql
@@ -0,0 +1,161 @@
+-- SWH DB schema upgrade
+-- from_version: 114
+-- to_version: 115
+-- description: Add snapshot models
+
+insert into dbversion(version, release, description)
+      values(115, now(), 'Work In Progress');
+
+CREATE SEQUENCE snapshot_branch_object_id_seq
+	START WITH 1
+	INCREMENT BY 1
+	NO MAXVALUE
+	NO MINVALUE
+	CACHE 1;
+
+CREATE SEQUENCE snapshot_object_id_seq
+	START WITH 1
+	INCREMENT BY 1
+	NO MAXVALUE
+	NO MINVALUE
+	CACHE 1;
+
+CREATE TYPE snapshot_target AS ENUM (
+	'content',
+	'directory',
+	'revision',
+	'release',
+	'snapshot',
+	'alias'
+);
+
+CREATE TYPE snapshot_result AS (
+	snapshot_id sha1_git,
+	name bytea,
+	target bytea,
+	target_type snapshot_target
+);
+
+CREATE TABLE snapshot (
+	object_id bigint DEFAULT nextval('snapshot_object_id_seq'::regclass) NOT NULL,
+	id sha1_git
+);
+
+CREATE TABLE snapshot_branch (
+	object_id bigint DEFAULT nextval('snapshot_branch_object_id_seq'::regclass) NOT NULL,
+	name bytea NOT NULL,
+	target bytea,
+	target_type snapshot_target
+);
+
+CREATE TABLE snapshot_branches (
+	snapshot_id bigint NOT NULL,
+	branch_id bigint NOT NULL
+);
+
+ALTER TABLE occurrence_history
+	ADD COLUMN snapshot_branch_id bigint;
+
+ALTER TABLE origin_visit
+	ADD COLUMN snapshot_id bigint;
+
+COMMENT ON COLUMN origin_visit.snapshot_id IS 'id of the snapshot associated with the visit';
+
+ALTER SEQUENCE snapshot_branch_object_id_seq
+	OWNED BY snapshot_branch.object_id;
+
+ALTER SEQUENCE snapshot_object_id_seq
+	OWNED BY snapshot.object_id;
+
+CREATE OR REPLACE FUNCTION swh_mktemp_snapshot_branch() RETURNS void
+    LANGUAGE sql
+    AS $$
+  create temporary table tmp_snapshot_branch (
+      name bytea not null,
+      target bytea,
+      target_type snapshot_target
+  ) on commit drop;
+$$;
+
+CREATE OR REPLACE FUNCTION swh_snapshot_add(origin bigint, visit bigint, snapshot_id sha1_git) RETURNS void
+    LANGUAGE plpgsql
+    AS $$
+declare
+  snapshot_object_id snapshot.object_id%type;
+begin
+  select object_id from snapshot where id = snapshot_id into snapshot_object_id;
+  if snapshot_object_id is null then
+     insert into snapshot (id) values (snapshot_id) returning object_id into snapshot_object_id;
+     with all_branches(name, target_type, target) as (
+       select name, target_type, target from tmp_snapshot_branch
+     ), inserted as (
+       insert into snapshot_branch (name, target_type, target)
+       select name, target_type, target from all_branches
+       on conflict do nothing
+       returning object_id
+     )
+     insert into snapshot_branches (snapshot_id, branch_id)
+     select snapshot_object_id, object_id as branch_id from inserted
+     union all
+     select snapshot_object_id, object_id as branch_id
+       from all_branches ab
+       join snapshot_branch sb
+         on sb.name = ab.name
+           and sb.target_type is not distinct from ab.target_type
+           and sb.target is not distinct from ab.target;
+  end if;
+  update origin_visit ov
+    set snapshot_id = snapshot_object_id
+    where ov.origin=swh_snapshot_add.origin and ov.visit=swh_snapshot_add.visit;
+end;
+$$;
+
+CREATE OR REPLACE FUNCTION swh_snapshot_get_by_id(id sha1_git) RETURNS SETOF snapshot_result
+    LANGUAGE sql STABLE
+    AS $$
+  select
+    swh_snapshot_get_by_id.id as snapshot_id, name, target, target_type
+  from snapshot_branches
+  inner join snapshot_branch on snapshot_branches.branch_id = snapshot_branch.object_id
+  where snapshot_id = (select object_id from snapshot where snapshot.id = swh_snapshot_get_by_id.id)
+$$;
+
+CREATE OR REPLACE FUNCTION swh_snapshot_get_by_origin_visit(origin_id bigint, visit_id bigint) RETURNS sha1_git
+    LANGUAGE sql STABLE
+    AS $$
+  select snapshot.id
+  from origin_visit
+  left join snapshot
+  on snapshot.object_id = origin_visit.snapshot_id
+  where origin_visit.origin=origin_id and origin_visit.visit=visit_id;
+$$;
+
+ALTER TABLE snapshot
+	ADD CONSTRAINT snapshot_pkey PRIMARY KEY (object_id);
+
+ALTER TABLE snapshot_branch
+	ADD CONSTRAINT snapshot_branch_pkey PRIMARY KEY (object_id);
+
+ALTER TABLE snapshot_branches
+	ADD CONSTRAINT snapshot_branches_pkey PRIMARY KEY (snapshot_id, branch_id);
+
+ALTER TABLE origin_visit
+	ADD CONSTRAINT origin_visit_snapshot_id_fkey FOREIGN KEY (snapshot_id) REFERENCES snapshot(object_id);
+
+ALTER TABLE snapshot_branch
+	ADD CONSTRAINT snapshot_branch_target_check CHECK (((target_type IS NULL) = (target IS NULL)));
+
+ALTER TABLE snapshot_branch
+	ADD CONSTRAINT snapshot_target_check CHECK (((target_type <> ALL (ARRAY['content'::snapshot_target, 'directory'::snapshot_target, 'revision'::snapshot_target, 'release'::snapshot_target, 'snapshot'::snapshot_target])) OR (length(target) = 20)));
+
+ALTER TABLE snapshot_branches
+	ADD CONSTRAINT snapshot_branches_branch_id_fkey FOREIGN KEY (branch_id) REFERENCES snapshot_branch(object_id);
+
+ALTER TABLE snapshot_branches
+	ADD CONSTRAINT snapshot_branches_snapshot_id_fkey FOREIGN KEY (snapshot_id) REFERENCES snapshot(object_id);
+
+CREATE UNIQUE INDEX snapshot_id_idx ON snapshot USING btree (id);
+
+CREATE UNIQUE INDEX snapshot_branch_name_idx ON snapshot_branch USING btree (name) WHERE ((target_type IS NULL) AND (target IS NULL));
+
+CREATE UNIQUE INDEX snapshot_branch_target_type_target_name_idx ON snapshot_branch USING btree (target_type, target, name);