Resolving the OverwriteModelError in mongoose - node.js

Question

Hi I wrote a Lambda function using nodejs to retrieve the data's from mongodb and it works fine. Later I use the API to produce link and to view the output in that link. Now the output is showed in console but in that API it showing OverwriteModel Error.I attached my code and output in API. What shall I do now ?
const mongoose = require('mongoose')
const models=()=>{
mongoose.connect('---',{useNewUrlParser:true,useCreateIndex:true,useUnifiedTopology:true})
const wavicle = mongoose.model('Datasetlist',{Dataset:[{id:Number,dataset:String,parameter:
{name:String}]}]})
const me = wavicle.find({})
return me
}
const main = async(event)=>{
console.log('EVENT:',event)
return models()
}
exports.handler = main
CONSOLE OUTPUT:
[
{
"_id": "5f05714c96db3e0007ae3595",
"Dataset": [
{
"parameter": [
{
"_id": "5f05714c96db3e0007ae3597",
"name": "StoreName"
},
{
"_id": "5f05714c96db3e0007ae3598",
"name": "Dates"
},
{
"_id": "5f05714c96db3e0007ae3599",
"name": "TransDesc"
},
{
"_id": "5f05714c96db3e0007ae359a",
"name": "Amount"
},
{
"_id": "5f05714c96db3e0007ae359b",
"name": "credit"
},
{
"_id": "5f05714c96db3e0007ae359c",
"name": "total"
}
],
"_id": "5f05714c96db3e0007ae3596",
"id": 1,
"dataset": "Daily Food Report"
}
],
"__v": 0
}
]
API OUTPUT:
{
"errorType": "OverwriteModelError",
"errorMessage": "Cannot overwrite `Datasetlist` model once compiled.",
"trace": [
"OverwriteModelError: Cannot overwrite `Datasetlist` model once compiled.",
" at Mongoose.model (/var/task/node_modules/mongoose/lib/index.js:524:13)",
" at models (/var/task/index.js:7:26)",
" at Runtime.main [as handler] (/var/task/index.js:18:12)",
" at Runtime.handleOnce (/var/runtime/Runtime.js:66:25)"
]
}

Answer 1

"errorType": "OverwriteModelError" signifies that you are over writting Datasetlist model
which already exist in your database under different Schema or same name like DataSetlist or DATASETLIST or dataSetlist .
First delete previous model.
Then run your code ,this time it will create new model without any error

Answer 2

I'm defining the mongodb connection and creating mongoose model inside the models function so every time it creating the mongoose model with same name and same schema repeatedly and overwriting so it's shows the error "overwritemodelerror". Now I had kept the mongoose model and mongodb connection part outside the models function
const mongoose = require('mongoose')
mongoose.connect('mongodb+srv://Sethu16:Sethu16##samplecluster.xtrb0.mongodb.net/Wavicle?retryWrites=true&w=majority',{useNewUrlParser:true,useCreateIndex:true,useUnifiedTopology:true})
const Wavicle = mongoose.model('Datasetlist',{Dataset:[{id:Number,dataset:String,parameter:[{name:String}]}]})
const models=()=>{
const me = Wavicle.find({})
return me
}
const main = async(event)=>{
console.log('EVENT:',event)
return models()
}
exports.handler = main
CONSOLE OUTPUT:
[
{
"_id": "5f05714c96db3e0007ae3595",
"Dataset": [
{
"parameter": [
{
"_id": "5f05714c96db3e0007ae3597",
"name": "StoreName"
},
{
"_id": "5f05714c96db3e0007ae3598",
"name": "Dates"
},
{
"_id": "5f05714c96db3e0007ae3599",
"name": "TransDesc"
},
{
"_id": "5f05714c96db3e0007ae359a",
"name": "Amount"
},
{
"_id": "5f05714c96db3e0007ae359b",
"name": "credit"
},
{
"_id": "5f05714c96db3e0007ae359c",
"name": "total"
}
],
"_id": "5f05714c96db3e0007ae3596",
"id": 1,
"dataset": "Daily Food Report"
}
],
"__v": 0
}
]
API OUTPUT:
[
{
"_id": "5f05714c96db3e0007ae3595",
"Dataset": [
{
"parameter": [
{
"_id": "5f05714c96db3e0007ae3597",
"name": "StoreName"
},
{
"_id": "5f05714c96db3e0007ae3598",
"name": "Dates"
},
{
"_id": "5f05714c96db3e0007ae3599",
"name": "TransDesc"
},
{
"_id": "5f05714c96db3e0007ae359a",
"name": "Amount"
},
{
"_id": "5f05714c96db3e0007ae359b",
"name": "credit"
},
{
"_id": "5f05714c96db3e0007ae359c",
"name": "total"
}
],
"_id": "5f05714c96db3e0007ae3596",
"id": 1,
"dataset": "Daily Food Report"
}
],
"__v": 0
}
]