Add IF NOT EXISTS to extensions as used in multiple places

Plus 1 insert date range correction

Author: kmoppel

07_1_table_partitioning_range.sql

@@ -34,7 +34,7 @@ CREATE TABLE orders_y2019 PARTITION OF orders FOR VALUES FROM ('2019-01-01') TO
 
 -- we keep working with the "main" table ...
 INSERT INTO orders
-    SELECT 1;
+    SELECT 1, '2019-01-01 01:00';
 
 SELECT * FROM orders; -- 1 row
 

07_4_table_partitioning_multi_level.sql

@@ -19,6 +19,8 @@ conditions.
 -- when lots of sub-partitions can be forseen then it's a good idea to move them into a separate schema
 CREATE SCHEMA subpartitions AUTHORIZATION demorole;
 
+CREATE EXTENSION IF NOT EXISTS btree_gin;
+
 SET ROLE TO demorole;
 
 -- used to "instantiate" separate metric definitions

80_advanced_indexing.sql

@@ -65,7 +65,7 @@ CREATE INDEX ON main_datatypes(substring(text_data1, 1, 3));
 /* GIN */
 RESET role;     -- superuser needed for creating extensions and using COPY PROGRAM
 
-CREATE EXTENSION btree_gin; -- needed for indexing some "usual" datatypes like integers
+CREATE EXTENSION IF NOT EXISTS btree_gin; -- needed for indexing some "usual" datatypes like integers
 -- when we compare the B-tree and the GIN index we see that the latter is ~10x smaller
 CREATE INDEX ON banking.account USING gin (teller_id);
 
@@ -83,7 +83,7 @@ CREATE INDEX ON main_datatypes USING gin (json_data jsonb_path_ops);
 
 -- implementing exclusion constraints - ensure no time overlappings are possible
 
-CREATE EXTENSION btree_gist;
+CREATE EXTENSION IF NOT EXISTS btree_gist;
 
 CREATE TABLE public.room_reservation (
     room text,
@@ -98,7 +98,7 @@ ALTER TABLE public.room_reservation OWNER TO demorole;
 CREATE TABLE fuzzy_search (name text);
 ALTER TABLE fuzzy_search OWNER TO demorole;
 
-CREATE EXTENSION pg_trgm;
+CREATE EXTENSION IF NOT EXISTS pg_trgm;
 
 COPY fuzzy_search FROM PROGRAM 'curl www.cybertec.at/secret/orte.txt';  -- ~2k names