diff --git a/src/lib/Hydra/Schema/Builds.pm b/src/lib/Hydra/Schema/Builds.pm
index 53454867..937bd5fc 100644
--- a/src/lib/Hydra/Schema/Builds.pm
+++ b/src/lib/Hydra/Schema/Builds.pm
@@ -68,7 +68,7 @@ __PACKAGE__->table("builds");
 
   data_type: 'integer'
   is_foreign_key: 1
-  is_nullable: 1
+  is_nullable: 0
 
 =head2 job
 
@@ -222,7 +222,7 @@ __PACKAGE__->add_columns(
   "jobset",
   { data_type => "text", is_foreign_key => 1, is_nullable => 0 },
   "jobset_id",
-  { data_type => "integer", is_foreign_key => 1, is_nullable => 1 },
+  { data_type => "integer", is_foreign_key => 1, is_nullable => 0 },
   "job",
   { data_type => "text", is_foreign_key => 1, is_nullable => 0 },
   "nixname",
@@ -466,12 +466,7 @@ __PACKAGE__->belongs_to(
   "jobset",
   "Hydra::Schema::Jobsets",
   { id => "jobset_id" },
-  {
-    is_deferrable => 0,
-    join_type     => "LEFT",
-    on_delete     => "CASCADE",
-    on_update     => "NO ACTION",
-  },
+  { is_deferrable => 0, on_delete => "CASCADE", on_update => "NO ACTION" },
 );
 
 =head2 jobset_project_jobset
@@ -578,8 +573,8 @@ __PACKAGE__->many_to_many(
 );
 
 
-# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-06 12:32:28
-# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:RvrINOAowDcde8Nd9VD6rQ
+# Created by DBIx::Class::Schema::Loader v0.07049 @ 2020-02-06 12:34:25
+# DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:EEXlcKN/ydXJ129vT0jTUw
 
 __PACKAGE__->has_many(
   "dependents",
diff --git a/src/sql/hydra.sql b/src/sql/hydra.sql
index f6c05bf7..f1d143dc 100644
--- a/src/sql/hydra.sql
+++ b/src/sql/hydra.sql
@@ -170,7 +170,7 @@ create table Builds (
     -- Info about the inputs.
     project       text not null,
     jobset        text not null,
-    jobset_id     integer null,
+    jobset_id     integer not null,
     job           text not null,
 
     -- Info about the build result.
diff --git a/src/sql/upgrade-64.sql b/src/sql/upgrade-64.sql
new file mode 100644
index 00000000..76afa9e7
--- /dev/null
+++ b/src/sql/upgrade-64.sql
@@ -0,0 +1,7 @@
+-- Make the Builds.jobset_id column NOT NULL. If this upgrade fails,
+-- either the admin didn't run the backfiller or there is a bug. If
+-- the admin ran the backfiller and there are null columns, it is
+-- very important to figure out where the nullable columns came from.
+
+ALTER TABLE Builds
+  ALTER COLUMN jobset_id SET NOT NULL;