diff --git a/dba/caldav_functions.sql b/dba/caldav_functions.sql
index 9733a007..3c698759 100644
--- a/dba/caldav_functions.sql
+++ b/dba/caldav_functions.sql
@@ -387,8 +387,8 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql;
 
-DROP FUNCTION rename_davical_user( TEXT, TEXT );
-DROP TRIGGER usr_modified ON usr CASCADE;
+DROP FUNCTION IF EXISTS rename_davical_user( TEXT, TEXT );
+DROP TRIGGER IF EXISTS usr_modified ON usr CASCADE;
 CREATE or REPLACE FUNCTION usr_modified() RETURNS TRIGGER AS $$
 DECLARE
   oldpath TEXT;
@@ -412,7 +412,7 @@ CREATE TRIGGER usr_modified AFTER UPDATE ON usr
     FOR EACH ROW EXECUTE PROCEDURE usr_modified();
 
 
-DROP TRIGGER collection_modified ON collection CASCADE;
+DROP TRIGGER IF EXISTS collection_modified ON collection CASCADE;
 CREATE or REPLACE FUNCTION collection_modified() RETURNS TRIGGER AS $$
 DECLARE
 BEGIN
@@ -439,7 +439,7 @@ CREATE TRIGGER collection_modified AFTER UPDATE OR DELETE ON collection
     FOR EACH ROW EXECUTE PROCEDURE collection_modified();
 
 
-DROP TRIGGER caldav_data_modified ON caldav_data CASCADE;
+DROP TRIGGER IF EXISTS caldav_data_modified ON caldav_data CASCADE;
 CREATE or REPLACE FUNCTION caldav_data_modified() RETURNS TRIGGER AS $$
 DECLARE
   coll_id caldav_data.collection_id%TYPE;
@@ -486,8 +486,8 @@ CREATE TRIGGER caldav_data_modified AFTER INSERT OR UPDATE OR DELETE ON caldav_d
     FOR EACH ROW EXECUTE PROCEDURE caldav_data_modified();
 
 
-DROP TRIGGER caldav_data_sync_dav_id ON caldav_data CASCADE;
-DROP TRIGGER calendar_item_sync_dav_id ON calendar_item CASCADE;
+DROP TRIGGER IF EXISTS caldav_data_sync_dav_id ON caldav_data CASCADE;
+DROP TRIGGER IF EXISTS calendar_item_sync_dav_id ON calendar_item CASCADE;
 CREATE or REPLACE FUNCTION sync_dav_id ( ) RETURNS TRIGGER AS $$
   DECLARE
   BEGIN
@@ -1116,7 +1116,7 @@ END;
 $$ LANGUAGE plpgsql IMMUTABLE STRICT;
 
 
-DROP TRIGGER principal_modified ON principal CASCADE;
+DROP TRIGGER IF EXISTS principal_modified ON principal CASCADE;
 CREATE or REPLACE FUNCTION principal_modified() RETURNS TRIGGER AS $$
 DECLARE
 BEGIN
@@ -1135,7 +1135,7 @@ CREATE TRIGGER principal_modified AFTER UPDATE ON principal
     FOR EACH ROW EXECUTE PROCEDURE principal_modified();
 
 
-DROP TRIGGER grants_modified ON grants CASCADE;
+DROP TRIGGER IF EXISTS grants_modified ON grants CASCADE;
 CREATE or REPLACE FUNCTION grants_modified() RETURNS TRIGGER AS $$
 DECLARE
   old_to_principal INT8;
@@ -1257,7 +1257,7 @@ END
 $$ LANGUAGE plpgsql STRICT;
 
 
-DROP TRIGGER alarm_changed ON calendar_alarm CASCADE;
+DROP TRIGGER IF EXISTS alarm_changed ON calendar_alarm CASCADE;
 CREATE or REPLACE FUNCTION alarm_changed() RETURNS TRIGGER AS $$
 DECLARE
   oldcomponent TEXT;
diff --git a/dba/rrule_functions.sql b/dba/rrule_functions.sql
index 11691034..9df816b1 100644
--- a/dba/rrule_functions.sql
+++ b/dba/rrule_functions.sql
@@ -26,7 +26,7 @@
 */
 
 -- Create a composite type for the parts of the RRULE.
-DROP TYPE rrule_parts CASCADE;
+DROP TYPE IF EXISTS rrule_parts CASCADE;
 CREATE TYPE rrule_parts AS (
   base TIMESTAMP WITH TIME ZONE,
   until TIMESTAMP WITH TIME ZONE,
@@ -680,7 +680,7 @@ $$ LANGUAGE plpgsql IMMUTABLE;
 
 
 -- Create a composite type for the parts of the RRULE.
-DROP TYPE rrule_instance CASCADE;
+DROP TYPE IF EXISTS rrule_instance CASCADE;
 CREATE TYPE rrule_instance AS (
   dtstart TIMESTAMP WITH TIME ZONE,
   rrule TEXT,
diff --git a/dba/views/dav_principal.sql b/dba/views/dav_principal.sql
index 1950c084..4f318c21 100644
--- a/dba/views/dav_principal.sql
+++ b/dba/views/dav_principal.sql
@@ -2,7 +2,7 @@
 -- record 1:1 with the principal table
 
 
-DROP VIEW dav_principal CASCADE;
+DROP VIEW IF EXISTS dav_principal CASCADE;
 CREATE OR REPLACE VIEW dav_principal AS
   SELECT user_no, usr.active AS user_active, joined AS created, updated AS modified,
          username, password, fullname, email,
diff --git a/debian/README.Debian b/debian/README.Debian
index 05f30a42..6d5fd85a 100644
--- a/debian/README.Debian
+++ b/debian/README.Debian
@@ -15,6 +15,8 @@ version, for Debian Jessie try /etc/postgresql/9.4/main/pg_hba.conf):
     local   davical    davical_app   trust
     local   davical    davical_dba   trust
 
+Don't forget to restart postgres for the change to take effect!
+
 2. Create the database, noting the displayed DAViCal admin password:
 
     sudo -u postgres /usr/share/davical/dba/create-database.sh