diff --git a/sql/schema.sql b/sql/schema.sql
index f597797..ff264a8 100644
--- a/sql/schema.sql
+++ b/sql/schema.sql
@@ -13,7 +13,7 @@ CREATE TABLE contents (
 
 CREATE TABLE packages (
   id       SERIAL    PRIMARY KEY,
-  system   integer   NOT NULL REFERENCES systems(id),
+  system   integer   NOT NULL REFERENCES systems(id) ON DELETE CASCADE,
   category varchar,
   name     varchar   NOT NULL,
   UNIQUE(system, name, category) -- Note the order, lookups on (system,name) are common
@@ -21,14 +21,14 @@ CREATE TABLE packages (
 
 CREATE TABLE package_versions (
   id       SERIAL    PRIMARY KEY,
-  package  integer   NOT NULL REFERENCES packages(id),
+  package  integer   NOT NULL REFERENCES packages(id) ON DELETE CASCADE,
   version  varchar   NOT NULL,
   released date      NOT NULL,
   UNIQUE(package, version)
 );
 
 CREATE TABLE man (
-  package  integer   NOT NULL REFERENCES package_versions(id),
+  package  integer   NOT NULL REFERENCES package_versions(id) ON DELETE CASCADE,
   name     varchar   NOT NULL,
   section  varchar   NOT NULL,
   filename varchar   NOT NULL,
diff --git a/sql/update-2016-10-06.sql b/sql/update-2016-10-06.sql
new file mode 100644
index 0000000..ff4b394
--- /dev/null
+++ b/sql/update-2016-10-06.sql
@@ -0,0 +1,3 @@
+ALTER TABLE packages DROP CONSTRAINT packages_system_fkey, ADD CONSTRAINT packages_system_fkey FOREIGN KEY(system) REFERENCES systems(id) ON DELETE CASCADE;
+ALTER TABLE package_versions DROP CONSTRAINT package_versions_package_fkey, ADD CONSTRAINT package_versions_package_fkey FOREIGN KEY(package) REFERENCES packages(id) ON DELETE CASCADE;
+ALTER TABLE man DROP CONSTRAINT man_package_fkey, ADD CONSTRAINT man_package_fkey FOREIGN KEY(package) REFERENCES package_versions(id) ON DELETE CASCADE;