# Prisma, how to clear the database

> Learn how to clear a database with Prisma using deleteMany, and how to delete related records in order with findMany and Promise.all to respect relations.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2021-07-14 | Topics: [Database](https://flaviocopes.com/tags/database/) | Canonical: https://flaviocopes.com/prisma-clear-database/

While testing a site that used [Prisma](https://flaviocopes.com/prisma/) I had the need to clear the database from time to time, to clear the test data I entered.

You can clear items entered by using:

```js
await prisma.user.deleteMany({})
```

If for some reason you want to iterate on the items to do some processing, you can iterate over them in this way:

```js
const users = await prisma.user.findMany({})

const deleteUser = async (user) => {
  return await prisma.user.delete({
    where: { id: user.id }
  })
}

const deleteUsers = async () => {
  users.map((user) => deleteUser(user))
}

deleteUsers()
```

In this case I am not doing anything more than the previous example, which makes all this code redundant, but you could do anything you want inside `deleteUser()`.

I had a problem though because I had a relation between 2 tables, tweets and users. A tweet was associated to a user. First I had to remove all tweets, then remove all users, so I wrote this function:

```js
export const clearData = async (prisma) => {
  const users = await prisma.user.findMany({})
  const tweets = await prisma.tweet.findMany({})

  const deleteUser = async (user) => {
    return await prisma.user.delete({
      where: { id: user.id }
    })
  }
  const deleteTweet = async (tweet) => {
    return await prisma.tweet.delete({
      where: { id: tweet.id }
    })
  }

  const deleteTweets = async () => {
    return Promise.all(tweets.map((tweet) => deleteTweet(tweet)))
  }

  const deleteUsers = async () => {
    return Promise.all(users.map((user) => deleteUser(user)))
  }

  await deleteTweets()
  await deleteUsers()
}
```

Notice the use of `Promise.all()` to wrap `users.map()` so I could use `await` on it, so all tweets are removed before I start deleting users.