Can you get good error messages for schema validaiton, on existing data?

[Alex_Bjorlig (Alex Bjørlig)]

Hi there.
My objective is to upgrade an existing mongo database to enforce schemas. Reading this blog, it seems like version 5 actually gives good error messages on insert/update.

But how do I get these error messages for existing data?

This section from compass is to no help (for complex objects that is):

[kevinadi (Kevin Adistambha)]

Hi @Alex_Bjorlig

You can validate existing data using db.collection.validate():

db.collection.validate() also validates any documents that violate the collection’s schema validation rules.

Hope this helps.

Best regards
Kevin

[Alex_Bjorlig (Alex Bjørlig)]

I don’t seem to get schema validation erros as output, just something like this:

"validateOutput": {
        "ns": "21risk.sessions",
        "nInvalidDocuments": 0,
        "nrecords": 181856,
        "nIndexes": 2,
        "keysPerIndex": {
            "_id_": 181856,
            "expires_1": 181856
        },
        "indexDetails": {
            "_id_": {
                "valid": true
            },
            "expires_1": {
                "valid": true
            }
        },
        "valid": true,
        "repaired": false,
        "warnings": [],
        "errors": [],
        "extraIndexEntries": [],
        "missingIndexEntries": [],
        "corruptRecords": [],
        "ok": 1,
        "$clusterTime": {
            "clusterTime": {
                "$timestamp": "7125046445631078401"
            },
            "signature": {
                "hash": "Kq8B4EiRRx5Q7A7Wk1faUpcRfUk=",
                "keyId": {
                    "low": 2,
                    "high": 1646856462,
                    "unsigned": false
                }
            }
        },
        "operationTime": {
            "$timestamp": "7125046445631078401"
        }
    }

With the node.js driver, I call the validate like this validateOutput = await db.admin().validateCollection(col.name);

But I don’t seem to have an option for setting full: true - as described in the docs here.

Workaround:

Currently I simply validate the schema with ajv:

import Ajv from 'ajv';
const ajv = new Ajv({ strict: false });
const validate = ajv.compile(validator.$jsonSchema);
  const result = validate(failedDoc);
  if (!result) {
    docSchemaErrors = validate.errors;
  }

@Stennie Just tagging you, because I can see in my forum searches that you seem to be the schema validation expert And my AJV workaround does not seem to work well in edge cases

[Alex_Bjorlig (Alex Bjørlig)]

For now I actually found it that the most pragmatic approach is simply to create a temporary collection, enforce schema validation, and then try to insert the document giving errors.
Works surprisingly well, and gives more stable results than using ajv.