completing draft

drafts/postgres_messaging_app.md

@@ -3,4 +3,36 @@
 Here is a funny idea I came up with : using postgres to make an instant
 messaging app. 
 
+## The tables
 
+First create a basic user table:
+
+    CREATE TABLE users (
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        username VARCHAR
+    );
+
+
+Then create a conversation table:
+
+    CREATE TABLE conversation (
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        name VARCHAR
+    );
+
+And a participant table:
+
+    CREATE TABLE participant (
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        user_id UUID REFERENCES users(id),
+        conversation_id UUID REFERENCES conversation(id)
+    );
+
+Then a message table :
+
+    CREATE TABLE message ( 
+        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+        sender_id UUID REFERENCES participant(id),
+        conversation_id UUID REFERENCES conversation(id),
+        content VARCHAR
+    );