Document how to delete all records from all tables

Sometimes it’s helpful to wipe all data records in the DB but keep the tables. This is currently not possible via the Prisma Client API so we should document a workaround.

One potential approach which currently doesn’t work because it relies on a private property of PrismaClient is this:

import { PrismaClient } from '@prisma/client'
const prisma = new PrismaClient()

function lowerCase(name: string): string {
  return name.substring(0, 1).toLowerCase() + name.substring(1)
}

const promises = prisma.dmmf.datamodel.models.map(model => {
  return new Promise(async resolve => {
    const modelName = lowerCase(model.name)
    const modelMethods = prisma[modelName]

    if (modelMethods) {
      try {
        resolve(await modelMethods.findMany({}))
      } catch (e) {
        resolve(e)
      }
    }
  }

async function main() {                    
  await Promise.all(promises)
}

main()

Alternatively, the following approach (by @nnennajohn) which is based on knex.js can be used:

import camelCase from 'lodash/camelCase';
import { prisma } from '@cpath/universal/shared/db';
import knexClient from './knex';
// Contents of the knexClient import above
// import Knex from 'knex';
// const knexClient: Knex = Knex({
//   client: 'pg',
//   connection: {
//     user: process.env.POSTGRES_USER,
//     password: process.env.POSTGRES_PASSWORD,
//     host: process.env.POSTGRES_HOST,
//     port: Number(process.env.POSTGRES_PORT),
//     database: process.env.POSTGRES_DB,
//   },
// });
// Contents of the prisma import above
// export const prisma = new PrismaClient();
function deleteRecords(tablesList) {
  const validTables = tablesList.filter((tableName) => tableName[0] !== '_');
  console.log('These are the valid tables', validTables);
  const recordsDeletions = validTables.map((table) => {
    return prisma[camelCase(table)].deleteMany({});
  });
  return Promise.all(recordsDeletions);
}
function listTables() {
  const query =
    'SELECT table_name FROM information_schema.tables WHERE table_schema = current_schema() AND table_catalog = ?';
  const bindings = [knexClient.client.database()];
  return knexClient.raw(query, bindings).then((results) => {
    return results.rows.map((row) => row.table_name);
  });
}
async function main() {
  const tablesList = await listTables();
  console.log('This is the list of knex tables', tablesList);
  if (tablesList && tablesList.length) {
    deleteRecords(tablesList)
      .then((res) => {
        console.log('Successfully deleted table records', res);
      })
      .catch((err) => {
        console.log('Error deleting table records', err);
      });
  }
}
main()
  .catch((e) => console.error(e))
  .finally();

We should also document a workaround that allows to do this without an external dependency like knex.js.

[sorenbs]

I guess you could also do something like this:

const { PrismaClient } = require('@prisma/client')
const prisma = new PrismaClient()

const allProperties = Reflect.ownKeys(Object.getPrototypeOf(prisma))
const modelNames = allProperties.filter(x => x != "constructor" && x != "on" && x != "connect" && x != "runDisconnect" && x != "disconnect")

for (modelName of modelNames) {

    // handle async stuff
    prisma[modelName].deleteMany()
}

[kitze]

Maybe add a button in the data studio?