完成03-Database作业

database/graphql/message.graphql

@@ -1,5 +1,5 @@
-mutation addMessage($user_uuid: uuid!, $room_uuid: uuid!, $content: String!) {
-  insert_message_one(object: {user_uuid: $user_uuid, room_uuid: $room_uuid, content: $content}) {
+mutation addMessage($user_uuid: uuid!, $room_uuid: uuid!, $content: String!, $reply_to: uuid) {
+  insert_message_one(object: {user_uuid: $user_uuid, room_uuid: $room_uuid, content: $content, reply_to: $reply_to}) {
     uuid
   }
 }
@@ -13,5 +13,13 @@ subscription getMessagesByRoom($room_uuid: uuid!) {
     }
     content
     created_at
+    reply_to
+    replied_to {
+      uuid
+      content
+      user {
+        username
+      }
+    }
   }
 }

database/hasura/hasura_metadata.json

@@ -4,7 +4,7 @@
     "version": 3,
     "sources": [
       {
-        "name": "workshop",
+        "name": "web-workshop",
         "kind": "postgres",
         "tables": [
           {
@@ -13,6 +13,12 @@
               "schema": "public"
             },
             "object_relationships": [
+              {
+                "name": "replied_to",
+                "using": {
+                  "foreign_key_constraint_on": "reply_to"
+                }
+              },
               {
                 "name": "room",
                 "using": {
@@ -26,6 +32,20 @@
                 }
               }
             ],
+            "array_relationships": [
+              {
+                "name": "replies",
+                "using": {
+                  "foreign_key_constraint_on": {
+                    "column": "reply_to",
+                    "table": {
+                      "name": "message",
+                      "schema": "public"
+                    }
+                  }
+                }
+              }
+            ],
             "insert_permissions": [
               {
                 "role": "user",
@@ -34,6 +54,7 @@
                   "columns": [
                     "content",
                     "created_at",
+                    "reply_to",
                     "room_uuid",
                     "user_uuid",
                     "uuid"
@@ -49,6 +70,7 @@
                   "columns": [
                     "content",
                     "created_at",
+                    "reply_to",
                     "room_uuid",
                     "user_uuid",
                     "uuid"
@@ -65,6 +87,7 @@
                   "columns": [
                     "content",
                     "created_at",
+                    "reply_to",
                     "room_uuid",
                     "user_uuid",
                     "uuid"

database/hasura/metadata/databases/databases.yaml

@@ -1,9 +1,9 @@
-- name: workshop
+- name: web-workshop
   kind: postgres
   configuration:
     connection_info:
       database_url:
         from_env: PG_DATABASE_URL
       isolation_level: read-committed
       use_prepared_statements: false
-  tables: "!include workshop/tables/tables.yaml"
+  tables: "!include web-workshop/tables/tables.yaml"

database/hasura/metadata/databases/workshop/tables/public_message.yaml → database/hasura/metadata/databases/web-workshop/tables/public_message.yaml

@@ -2,19 +2,31 @@ table:
   name: message
   schema: public
 object_relationships:
+  - name: replied_to
+    using:
+      foreign_key_constraint_on: reply_to
   - name: room
     using:
       foreign_key_constraint_on: room_uuid
   - name: user
     using:
       foreign_key_constraint_on: user_uuid
+array_relationships:
+  - name: replies
+    using:
+      foreign_key_constraint_on:
+        column: reply_to
+        table:
+          name: message
+          schema: public
 insert_permissions:
   - role: user
     permission:
       check: {}
       columns:
         - content
         - created_at
+        - reply_to
         - room_uuid
         - user_uuid
         - uuid
@@ -25,6 +37,7 @@ select_permissions:
       columns:
         - content
         - created_at
+        - reply_to
         - room_uuid
         - user_uuid
         - uuid
@@ -36,6 +49,7 @@ update_permissions:
       columns:
         - content
         - created_at
+        - reply_to
         - room_uuid
         - user_uuid
         - uuid

database/sql/message.sql

@@ -5,12 +5,38 @@ create table if not exists public.message (
   room_uuid uuid not null,
   content text not null,
   created_at timestamp default current_timestamp not null,
+  reply_to uuid,
   primary key (uuid)
 );
 alter table public.message
 add constraint message_user_uuid_fkey foreign key (user_uuid) references public.user (uuid) on update cascade on delete cascade;
 alter table public.message
 add constraint message_room_uuid_fkey foreign key (room_uuid) references public.room (uuid) on update cascade on delete cascade;
+alter table public.message
+add constraint message_reply_to_fkey foreign key (reply_to) references public.message (uuid) on update cascade on delete set null;
+alter table public.message
+add constraint message_no_self_reply check (reply_to is null or reply_to <> uuid);
+alter table public.message
+add constraint message_reply_to_unique unique (reply_to);
+
+create or replace function public.check_message_reply() returns trigger as $$
+begin
+  if new.reply_to is not null then
+    if exists (
+      select 1 from public.message
+      where uuid = new.reply_to and reply_to is not null
+    ) then
+      raise exception 'cannot reply to a reply (multi-level reply is not allowed)';
+    end if;
+  end if;
+  return new;
+end;
+$$ language plpgsql;
+
+drop trigger if exists message_reply_check on public.message;
+create trigger message_reply_check
+before insert or update of reply_to on public.message
+for each row execute function public.check_message_reply();
 
 insert into public.message (user_uuid, room_uuid, content) values
 ('00000000-0000-0000-0000-000000000001', '00000000-0000-0000-0000-100000000001', '大家好，我叫张三'),
@@ -42,3 +68,8 @@ insert into public.message (user_uuid, room_uuid, content) values
 ('00000000-0000-0000-0000-000000000004', '00000000-0000-0000-0000-100000000003', '好了，今天就到这里吧');
 
 update public.message set created_at = '2021-01-01 00:00:00' where room_uuid = '00000000-0000-0000-0000-100000000002';
+
+insert into public.message (uuid, user_uuid, room_uuid, content) values
+('00000000-0000-0000-0000-000000000101', '00000000-0000-0000-0000-000000000001', '00000000-0000-0000-0000-100000000001', '有谁能听到我说话吗？');
+insert into public.message (uuid, user_uuid, room_uuid, content, reply_to) values
+('00000000-0000-0000-0000-000000000102', '00000000-0000-0000-0000-000000000002', '00000000-0000-0000-0000-100000000001', '我能听到，怎么啦？', '00000000-0000-0000-0000-000000000101');