diff --git a/sql/Makefile b/sql/Makefile
index c202da6..f3e3ee0 100644
--- a/sql/Makefile
+++ b/sql/Makefile
@@ -1,59 +1,61 @@
 # Depends: postgresql-client, postgresql-autodoc
 
 DBNAME = softwareheritage-dev
 DOCDIR = autodoc
 
 SQL_INIT    = swh-init.sql
 SQL_ENUMS   = swh-enums.sql
 SQL_SCHEMA  = swh-schema.sql
 SQL_FUNC    = swh-func.sql
 SQL_DATA    = swh-data.sql
 SQL_INDEX   = swh-indexes.sql
 SQL_TRIGGER = swh-triggers.sql
 SQLS = $(SQL_INIT) $(SQL_ENUMS) $(SQL_SCHEMA) $(SQL_FUNC) $(SQL_INDEX) $(SQL_TRIGGER) $(SQL_DATA)
 
 PSQL_BIN = psql
 PSQL_FLAGS = --echo-all -X -v ON_ERROR_STOP=1
 PSQL = $(PSQL_BIN) $(PSQL_FLAGS)
 
 all:
 
 createdb: createdb-stamp
 createdb-stamp: $(SQL_INIT)
 	createdb $(DBNAME)
 	touch $@
 
 filldb: filldb-stamp
 filldb-stamp: createdb-stamp
 	cat $(SQLS) | $(PSQL) $(DBNAME)
 	touch $@
 
 dropdb:
 	-dropdb $(DBNAME)
 
 dumpdb: swh.dump
 swh.dump: filldb-stamp
 	pg_dump -Fc $(DBNAME) > $@
 
-doc: autodoc-stamp $(DOCDIR)/db-schema.pdf $(DOCDIR)/db-schema.svg
-autodoc-stamp: filldb-stamp
+$(DOCDIR):
 	test -d $(DOCDIR)/ || mkdir $(DOCDIR)
+
+doc: autodoc-stamp $(DOCDIR)/db-schema.pdf $(DOCDIR)/db-schema.svg
+autodoc-stamp: filldb-stamp $(DOCDIR)
 	postgresql_autodoc -d $(DBNAME) -f $(DOCDIR)/db-schema
 	cp -a $(DOCDIR)/db-schema.dot $(DOCDIR)/db-schema.dot.orig
 	touch $@
 
-$(DOCDIR)/db-schema.dot: clusters.dot autodoc-stamp
+$(DOCDIR)/db-schema.dot: clusters.dot autodoc-stamp $(DOCDIR)
 	bin/dot_add_content $(DOCDIR)/db-schema.dot.orig clusters.dot > $(DOCDIR)/db-schema.dot
 
 $(DOCDIR)/db-schema.pdf: $(DOCDIR)/db-schema.dot autodoc-stamp
 	dot -T pdf $< > $@
 $(DOCDIR)/db-schema.svg: $(DOCDIR)/db-schema.dot autodoc-stamp
 	dot -T svg $< > $@
 
 clean:
 	rm -rf *-stamp $(DOCDIR)/
 
 distclean: clean dropdb
 	rm -f swh.dump
 
 .PHONY: all initdb createdb dropdb doc clean