diff --git a/prisma/migrations/20230808162407_tag_constraint/migration.sql b/prisma/migrations/20230808162407_tag_constraint/migration.sql
new file mode 100644
index 0000000..b4fa134
--- /dev/null
+++ b/prisma/migrations/20230808162407_tag_constraint/migration.sql
@@ -0,0 +1,8 @@
+/*
+  Warnings:
+
+  - A unique constraint covering the columns `[name,user_id]` on the table `tag` will be added. If there are existing duplicate values, this will fail.
+
+*/
+-- CreateIndex
+CREATE UNIQUE INDEX "tag_name_user_id_key" ON "tag"("name", "user_id");
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 39a8664..def61ec 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -82,6 +82,7 @@ model Tag {
   createdAt DateTime @default(now()) @map("created_at")
   updatedAt DateTime @updatedAt @map("updated_at")
 
+  @@unique([name, userId])
   @@map("tag")
 }
 
diff --git a/prisma/seed.ts b/prisma/seed.ts
index 82db7e3..80e5bb6 100644
--- a/prisma/seed.ts
+++ b/prisma/seed.ts
@@ -36,6 +36,17 @@ async function createUserWithDocumentsAndTags(index: number, numDocs: number) {
     },
   });
 
+  const createdTag = await prisma.tag.create({
+    data: {
+      name: `tag${index}`,
+      user: {
+        connect: {
+          id: createdUser.id,
+        },
+      },
+    },
+  });
+
   await Promise.all(
     createdUser.documents.map((doc) =>
       prisma.document.update({
@@ -44,16 +55,9 @@ async function createUserWithDocumentsAndTags(index: number, numDocs: number) {
         },
         data: {
           tags: {
-            create: [
-              {
-                name: `tag${index}`,
-                user: {
-                  connect: {
-                    id: createdUser.id,
-                  },
-                },
-              },
-            ],
+            connect: {
+              id: createdTag.id,
+            },
           },
         },
       }),