[feat] add initial database schema with tables, triggers, and views

database/main/profession_citation.sql

@@ -0,0 +1,14 @@
+create table profession_citation
+(
+    profession_id INTEGER not null
+        references profession
+            on delete cascade,
+    citation_id   INTEGER not null
+        references citation
+            on delete cascade,
+    primary key (profession_id, citation_id)
+);
+
+create index idx_profession_citation_cit
+    on profession_citation (citation_id);
+