Create property graph if not exists

test/sql/create_pg/create_if_not_exists.test

@@ -0,0 +1,68 @@
+
+
+require duckpgq
+
+statement ok
+CREATE TABLE Student(id BIGINT, name VARCHAR);
+
+statement ok
+CREATE TABLE know(src BIGINT, dst BIGINT, createDate BIGINT);
+
+statement ok
+CREATE TABLE School(school_name VARCHAR, school_id BIGINT, school_kind BIGINT);
+
+statement ok
+INSERT INTO Student VALUES (0, 'Daniel'), (1, 'Tavneet'), (2, 'Gabor'), (3, 'Peter');
+
+statement ok
+INSERT INTO know VALUES (0,1, 10), (0,2, 11), (0,3, 12), (1,2, 14), (1,3, 15), (2,3, 16);
+
+statement ok
+-CREATE PROPERTY GRAPH IF NOT EXISTS pg_all_properties
+VERTEX TABLES (
+    Student,
+    School  LABEL School IN School_kind (Hogeschool, University)
+    )
+EDGE TABLES (
+    know    SOURCE KEY ( src ) REFERENCES Student ( id )
+            DESTINATION KEY ( dst ) REFERENCES Student ( id )
+            LABEL Knows
+    )
+
+query I
+select count(*) from __duckpgq_internal where is_vertex_table;
+----
+2
+
+statement ok
+-CREATE PROPERTY GRAPH IF NOT EXISTS pg_all_properties
+VERTEX TABLES (
+    Student
+    )
+EDGE TABLES (
+    know    SOURCE KEY ( src ) REFERENCES Student ( id )
+            DESTINATION KEY ( dst ) REFERENCES Student ( id )
+            LABEL Knows
+    )
+
+query I
+select count(*) from __duckpgq_internal where is_vertex_table;
+----
+2
+
+statement ok
+-CREATE PROPERTY GRAPH IF NOT EXISTS snb
+VERTEX TABLES (
+    Student
+    )
+EDGE TABLES (
+    know    SOURCE KEY ( src ) REFERENCES Student ( id )
+            DESTINATION KEY ( dst ) REFERENCES Student ( id )
+            LABEL Knows
+    )
+
+query I
+select distinct property_graph from __duckpgq_internal order by property_graph desc;
+----
+snb
+pg_all_properties