Fixed insert trigger

Author: GuilhermeF03

code/server/sql/create_tables.sql

@@ -1,46 +1,133 @@
-begin;
-
-    create extension if not exists "pgcrypto";
-
-    create type resource_type as enum ('D', 'F');
-
-    create table if not exists workspace (
-        id char(16) primary key default encode(gen_random_bytes(8), 'hex'),
-        name text not null,
-        "isPrivate" boolean not null default false,
-        "createdAt" timestamp not null default now(),
-        members text[] not null default '{}'::text[] -- references "user"(email)
-    );
-
-    create table if not exists resource(
-        id char(16) primary key default encode(gen_random_bytes(8), 'hex'),
-        workspace char(16) not null references workspace(id) on delete cascade,
-        name text not null,
-        type resource_type not null,
-        "createdAt" timestamp not null default now(),
-        "updatedAt" timestamp not null default now(),
-        parent char(16) default null references resource(id) on delete cascade,
-        children char(16)[] not null default '{}'::char(16)[] -- references resource(id)
-    );
-
-    create table if not exists "user" (
-        id char(28) primary key,
-        name text not null,
-        email text not null unique,
-        "createdAt" timestamp not null default now()
-    );
-
-    -- Triggers
-    create or replace trigger on_workspace_insert_trigger
-        after insert on workspace
-        for each row execute function add_root_resource();
-
-    create or replace trigger on_resource_delete_trigger
-        after delete on resource
-        for each row execute function on_child_removed();
-
-    create or replace trigger on_resource_update_trigger
-        after update on resource
-        for each row execute function on_child_updated();
-
-commit;
+BEGIN;
+
+-- Create extension if it doesn't exist
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+-- Create enum type
+CREATE TYPE resource_type AS ENUM ('D', 'F');
+
+-- Create workspace table
+CREATE TABLE IF NOT EXISTS workspace (
+    id CHAR(16) PRIMARY KEY DEFAULT encode(gen_random_bytes(8), 'hex'),
+    name TEXT NOT NULL,
+    "isPrivate" BOOLEAN NOT NULL DEFAULT false,
+    "createdAt" TIMESTAMP NOT NULL DEFAULT now(),
+    members TEXT[] NOT NULL DEFAULT '{}'::TEXT[] -- references "user"(email)
+);
+
+-- Create resource table
+CREATE TABLE IF NOT EXISTS resource (
+    id CHAR(16) PRIMARY KEY DEFAULT encode(gen_random_bytes(8), 'hex'),
+    workspace CHAR(16) NOT NULL REFERENCES workspace(id) ON DELETE CASCADE,
+    name TEXT NOT NULL,
+    type resource_type NOT NULL,
+    "createdAt" TIMESTAMP NOT NULL DEFAULT now(),
+    "updatedAt" TIMESTAMP NOT NULL DEFAULT now(),
+    parent CHAR(16) DEFAULT NULL REFERENCES resource(id) ON DELETE CASCADE,
+    children CHAR(16)[] NOT NULL DEFAULT '{}'::CHAR(16)[] -- references resource(id)
+);
+
+-- Create user table
+CREATE TABLE IF NOT EXISTS "user" (
+    id CHAR(28) PRIMARY KEY,
+    name TEXT NOT NULL,
+    email TEXT NOT NULL UNIQUE,
+    "createdAt" TIMESTAMP NOT NULL DEFAULT now()
+);
+
+-- Trigger functions
+
+-- Resource is deleted -> Remove self from parent's children array
+    create or replace function on_child_removed() returns trigger as $$
+        begin
+            --- Check if parent resource exists
+            if old.parent is not null then
+                ---- Remove self from parent's children array
+                update resource
+                set children = array_remove(children, old.id)
+                where id = old.parent;
+            end if;
+            return old;
+        end;
+    $$ language plpgsql;
+
+-- Resource is updated -> Update new and old parent's children array
+    create or replace function on_child_updated() returns trigger as $$
+        begin
+            if new.parent = old.parent then
+                return new;
+            end if;
+            --- Append self to children array of new parent
+            if new.parent is not null then
+                update resource
+                set children = array_append(children, new.id)
+                where id = new.parent;
+            end if;
+            --- Remove self from children array of old parent
+            if old.parent is not null then
+                update resource
+                set children = array_remove(children, old.id)
+                where id = old.parent;
+            end if;
+            return new;
+        end;
+    $$ language plpgsql;
+
+-- NEW RESOURCE IS CREATED -> UPDATE SELF'S PARENT ID AND APPEND SELF TO PARENT'S CHILDREN ARRAY
+    create or replace function on_new_resource_created() returns trigger as $$
+        begin
+            --- parent_id is null
+            if new.parent is null then
+                if new.id != new.workspace then ---- Workspace resource with root as parent
+                    update resource
+                    set parent = new.workspace
+                    where id = new.id;
+                    ---- Append self to root resource's children array
+                    update resource
+                    set children = array_append(children, new.id)
+                    where id = new.workspace;
+                    return new;
+                else return new; ---- Root resource - do nothing
+                end if;
+                --- parent_id is not null
+            else
+                ---- check if parent resource exists
+                if not exists (select 1 from resource where id = new.parent) then
+                    raise exception 'Parent resource does not exist';
+                end if;
+                --- Append self to children array of parent resource
+                update resource
+                set children = array_append(children, new.id)
+                where id = new.parent;
+                return new;
+            end if;
+        end;
+    $$ language plpgsql;
+
+-- Add root resource to resource table when a workspace is created
+    create or replace function add_root_resource() returns trigger as $$
+        begin
+            insert into resource (id, workspace, name, type)
+            values (new.id, new.id, 'root', 'F');
+            return new;
+        end;
+    $$ language plpgsql;
+
+-- Create triggers
+CREATE OR REPLACE TRIGGER on_workspace_insert_trigger
+    AFTER INSERT ON workspace
+    FOR EACH ROW EXECUTE FUNCTION add_root_resource();
+
+CREATE OR REPLACE TRIGGER on_resource_delete_trigger
+    AFTER DELETE ON resource
+    FOR EACH ROW EXECUTE FUNCTION on_child_removed();
+
+CREATE OR REPLACE TRIGGER on_resource_update_trigger
+    AFTER UPDATE ON resource
+    FOR EACH ROW EXECUTE FUNCTION on_child_updated();
+
+CREATE OR REPLACE TRIGGER on_resource_insert_trigger
+    AFTER INSERT ON resource
+    FOR EACH ROW EXECUTE FUNCTION on_new_resource_created();
+
+COMMIT;

code/server/sql/drop_tables.sql

@@ -3,5 +3,4 @@ begin ;
     drop table if exists resource cascade;
     drop table if exists workspace cascade;
     drop type if exists resource_type cascade;
-
 commit ;