diff --git a/schema/0012_newtype.sql b/schema/0012_newtype.sql
index 12c01cc..a6c9b6c 100644
--- a/schema/0012_newtype.sql
+++ b/schema/0012_newtype.sql
@@ -12,5 +12,15 @@ begin
                 , qualified_name || '_of_string(val text)'
                 , ' returns ' || qualified_name || E' language sql as \'select row(val);\';'
                 );
+  execute concat( 'create cast '
+                , ' (' || qualified_name || ' as text)'
+                , ' with function ' || qualified_name || E'_to_string(' || qualified_name || ')'
+                , ' as assignment;'
+                );
+  execute concat( 'create cast '
+                , ' (text as ' || qualified_name || ')'
+                , ' with function ' || qualified_name || E'_of_string(text)'
+                , ' as assignment;'
+                );
 end;
 $$;
diff --git a/scripts/build.sh b/scripts/build.sh
index 9b2a508..c2ba1d6 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -8,15 +8,6 @@ source ./scripts/env.sh ./.env.schema
 base_or_head="$1"
 rev="$2"
 
-docker compose kill "$base_or_head"
-docker compose rm -vf "$base_or_head"
-
-if [[ "$base_or_head" = "head" ]]; then
-  port=5433
-else
-  port=5432
-fi
-
 db() {
   echo -n "postgresql:///$1?port=$port&user=$POSTGRES_USER&password=$POSTGRES_PASSWORD"
 }
@@ -28,21 +19,34 @@ initdb() {
   psql --quiet $(db postgres) -c "create database dnim"
 }
 
+if [[ -n "$base_or_head" ]]; then
+  docker compose kill "$base_or_head"
+  docker compose rm -vf "$base_or_head"
+  
+  if [[ "$base_or_head" = "head" ]]; then
+    port=5433
+  else
+    port=5432
+  fi
+fi
+
 if [[ "$rev" = "empty" ]]; then
   docker compose up --wait --wait-timeout 30 -d "$base_or_head"
   initdb
   exit 0
 fi
 
-git worktree remove --force "./$base_or_head" &>/dev/null || true
-rm -rf "./$base_or_head" &>/dev/null || true
-git worktree add "./$base_or_head" --detach "$rev" &>/dev/null
+if [[ -n "$rev" ]]; then
+  git worktree remove --force "./$base_or_head" &>/dev/null || true
+  rm -rf "./$base_or_head" &>/dev/null || true
+  git worktree add "./$base_or_head" --detach "$rev" &>/dev/null
 
-cp docker-compose.yml "./$base_or_head/docker-compose.yml"
-cp .env.schema "./$base_or_head/.env.schema"
+  cp docker-compose.yml "./$base_or_head/docker-compose.yml"
+  cp .env.schema "./$base_or_head/.env.schema"
 
-cd "./$base_or_head"
-docker compose up --wait --wait-timeout 30 -d "$base_or_head"
+  cd "./$base_or_head"
+fi
 
+docker compose up --wait --wait-timeout 30 -d "${base_or_head:-head}"
 initdb
 ls ./schema/ | xargs -I{} bash -c "set -e; $(declare -f query_file); query_file \"$(db dnim)\" ./schema/{}"