budibase/packages/server/api/controllers/model.js

const CouchDB = require("../../db")

exports.fetch = async function(ctx) {
  const db = new CouchDB(ctx.params.instanceId)
  const body = await db.query("database/by_type", {
    include_docs: true,
    key: ["model"],
  })
  ctx.body = body.rows.map(row => row.doc)
}

exports.create = async function(ctx) {
  const db = new CouchDB(ctx.params.instanceId)
  const newModel = await db.post({
    type: "model",
    ...ctx.request.body,
  })

  const designDoc = await db.get("_design/database")
  designDoc.views = {
    ...designDoc.views,
    [`all_${newModel.id}`]: {
      map: `function(doc) {
        if (doc.modelId === "${newModel.id}") {
          emit(doc[doc.key], doc._id); 
        }
      }`,
    },
  }
  await db.put(designDoc)

  ctx.body = {
    message: `Model ${ctx.request.body.name} created successfully.`,
    status: 200,
    model: {
      _id: newModel.id,
      _rev: newModel.rev,
      ...ctx.request.body,
    },
  }
}

exports.update = async function(ctx) {}

exports.destroy = async function(ctx) {
  const db = new CouchDB(ctx.params.instanceId)

  const model = await db.remove(ctx.params.modelId, ctx.params.revId)
  const modelViewId = `all_${model.id}`

  // Delete all records for that model
  const records = await db.query(`database/${modelViewId}`)
  await db.bulkDocs(
    records.rows.map(record => ({ id: record.id, _deleted: true }))
  )

  // delete the "all" view
  const designDoc = await db.get("_design/database")
  delete designDoc.views[modelViewId]
  await db.put(designDoc)

  ctx.body = {
    message: `Model ${model.id} deleted.`,
    status: 200,
  }
}