diff --git a/src/lib/Hydra/Schema/JobsetEvals.pm b/src/lib/Hydra/Schema/JobsetEvals.pm
index 5558b39ad..7e88c25e3 100644
--- a/src/lib/Hydra/Schema/JobsetEvals.pm
+++ b/src/lib/Hydra/Schema/JobsetEvals.pm
@@ -89,6 +89,11 @@ __PACKAGE__->table("jobsetevals");
   data_type: 'integer'
   is_nullable: 1
 
+=head2 flake
+
+  data_type: 'text'
+  is_nullable: 1
+
 =cut
 
 __PACKAGE__->add_columns(
@@ -117,6 +122,8 @@ __PACKAGE__->add_columns(
   { data_type => "integer", is_nullable => 1 },
   "nrsucceeded",
   { data_type => "integer", is_nullable => 1 },
+  "flake",
+  { data_type => "text", is_nullable => 1 },
 );
 
 =head1 PRIMARY KEY
@@ -194,8 +201,8 @@ __PACKAGE__->belongs_to(
 );
 
 
-# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-06 12:22:36
-# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:4ZaT8Z1tmCCt6k4ein0MNg
+# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-09 15:21:11
+# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:Ar6GRni8AcAQmuZyg6tFKw
 
 __PACKAGE__->has_many(
   "buildIds",
diff --git a/src/lib/Hydra/Schema/Jobsets.pm b/src/lib/Hydra/Schema/Jobsets.pm
index a69bd5990..9e9d4773b 100644
--- a/src/lib/Hydra/Schema/Jobsets.pm
+++ b/src/lib/Hydra/Schema/Jobsets.pm
@@ -54,12 +54,12 @@ __PACKAGE__->table("jobsets");
 =head2 nixexprinput
 
   data_type: 'text'
-  is_nullable: 0
+  is_nullable: 1
 
 =head2 nixexprpath
 
   data_type: 'text'
-  is_nullable: 0
+  is_nullable: 1
 
 =head2 errormsg
 
@@ -137,6 +137,17 @@ __PACKAGE__->table("jobsets");
   data_type: 'integer'
   is_nullable: 1
 
+=head2 type
+
+  data_type: 'integer'
+  default_value: 0
+  is_nullable: 0
+
+=head2 flake
+
+  data_type: 'text'
+  is_nullable: 1
+
 =cut
 
 __PACKAGE__->add_columns(
@@ -147,9 +158,9 @@ __PACKAGE__->add_columns(
   "description",
   { data_type => "text", is_nullable => 1 },
   "nixexprinput",
-  { data_type => "text", is_nullable => 0 },
+  { data_type => "text", is_nullable => 1 },
   "nixexprpath",
-  { data_type => "text", is_nullable => 0 },
+  { data_type => "text", is_nullable => 1 },
   "errormsg",
   { data_type => "text", is_nullable => 1 },
   "errortime",
@@ -178,6 +189,10 @@ __PACKAGE__->add_columns(
   { data_type => "boolean", is_nullable => 1 },
   "starttime",
   { data_type => "integer", is_nullable => 1 },
+  "type",
+  { data_type => "integer", default_value => 0, is_nullable => 0 },
+  "flake",
+  { data_type => "text", is_nullable => 1 },
 );
 
 =head1 PRIMARY KEY
@@ -335,8 +350,8 @@ __PACKAGE__->has_many(
 );
 
 
-# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-06 12:22:36
-# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:fYKx6VRlNG5XiDZ73Qr6Rw
+# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-09 15:21:11
+# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:FVP1/AWjdKTlY6djrG592A
 
 my %hint = (
     columns => [
diff --git a/src/sql/hydra.sql b/src/sql/hydra.sql
index 0c769a7e5..33ecab4dd 100644
--- a/src/sql/hydra.sql
+++ b/src/sql/hydra.sql
@@ -54,8 +54,8 @@ create table Jobsets (
     name          text not null,
     project       text not null,
     description   text,
-    nixExprInput  text not null, -- name of the jobsetInput containing the Nix or Guix expression
-    nixExprPath   text not null, -- relative path of the Nix or Guix expression
+    nixExprInput  text, -- name of the jobsetInput containing the Nix or Guix expression
+    nixExprPath   text, -- relative path of the Nix or Guix expression
     errorMsg      text, -- used to signal the last evaluation error etc. for this jobset
     errorTime     integer, -- timestamp associated with errorMsg
     lastCheckedTime integer, -- last time the evaluator looked at this jobset
@@ -70,7 +70,11 @@ create table Jobsets (
     fetchErrorMsg text,
     forceEval     boolean,
     startTime     integer, -- if jobset is currently running
+    type          integer not null default 0, -- 0 == legacy, 1 == flake
+    flake         text,
     check (schedulingShares > 0),
+    check ((type = 0) = (nixExprInput is not null and nixExprPath is not null)),
+    check ((type = 1) = (flake is not null)),
     primary key   (project, name),
     foreign key   (project) references Projects(name) on delete cascade on update cascade
 #ifdef SQLITE
@@ -181,7 +185,8 @@ create table Builds (
 
     -- Copy of the nixExprInput/nixExprPath fields of the jobset that
     -- instantiated this build.  Needed if we want to reproduce this
-    -- build.
+    -- build.  FIXME: this should be stored in JobsetEvals, storing it
+    -- here is denormal.
     nixExprInput  text,
     nixExprPath   text,
 
@@ -522,6 +527,8 @@ create table JobsetEvals (
     nrBuilds      integer,
     nrSucceeded   integer, -- set lazily when all builds are finished
 
+    flake         text, -- immutable flake reference
+
     foreign key   (project) references Projects(name) on delete cascade on update cascade,
     foreign key   (project, jobset) references Jobsets(project, name) on delete cascade on update cascade
 );
diff --git a/src/sql/upgrade-58.sql b/src/sql/upgrade-58.sql
new file mode 100644
index 000000000..b59ee9497
--- /dev/null
+++ b/src/sql/upgrade-58.sql
@@ -0,0 +1,7 @@
+alter table Jobsets alter column nixExprInput drop not null;
+alter table Jobsets alter column nixExprPath drop not null;
+alter table Jobsets add column type integer default 0;
+alter table Jobsets add column flake text;
+alter table Jobsets add check ((type = 0) = (nixExprInput is not null and nixExprPath is not null));
+alter table Jobsets add check ((type = 1) = (flake is not null));
+alter table JobsetEvals add column flake text;