added support for nested collection (backend)

prisma/migrations/20240125124457_added_subcollection_relations/migration.sql

@@ -0,0 +1,5 @@
+-- AlterTable
+ALTER TABLE "Collection" ADD COLUMN     "parentId" INTEGER;
+
+-- AddForeignKey
+ALTER TABLE "Collection" ADD CONSTRAINT "Collection_parentId_fkey" FOREIGN KEY ("parentId") REFERENCES "Collection"("id") ON DELETE SET NULL ON UPDATE CASCADE;

prisma/schema.prisma

@@ -69,17 +69,20 @@ model VerificationToken {
 }
 
 model Collection {
-  id          Int                   @id @default(autoincrement())
-  name        String
-  description String                @default("")
-  color       String                @default("#0ea5e9")
-  isPublic    Boolean               @default(false)
-  owner       User                  @relation(fields: [ownerId], references: [id])
-  ownerId     Int
-  members     UsersAndCollections[]
-  links       Link[]
-  createdAt   DateTime              @default(now())
-  updatedAt   DateTime              @default(now()) @updatedAt
+  id              Int                   @id @default(autoincrement())
+  name            String
+  description     String                @default("")
+  color           String                @default("#0ea5e9")
+  parentId        Int?
+  parent          Collection?           @relation("SubCollections", fields: [parentId], references: [id])
+  subCollections  Collection[]          @relation("SubCollections")
+  isPublic        Boolean               @default(false)
+  owner           User                  @relation(fields: [ownerId], references: [id])
+  ownerId         Int
+  members         UsersAndCollections[]
+  links           Link[]
+  createdAt       DateTime              @default(now())
+  updatedAt       DateTime              @default(now()) @updatedAt
 
   @@unique([name, ownerId])
 }