MongoDB/Mongoose按属性查询无法找到文档问题求助

Hey there, let's figure out why you can't query your Visit documents with Mongoose 5.0.11. I'll walk you through the most common checks and fixes step by step:

1. Verify Your Remote MongoDB Connection First #

Since your MongoDB is hosted remotely, start by confirming your connection is solid:

• Double-check your connection string includes the correct remote host, port, database name, and credentials (if enabled).
• Add success/error logging to your Mongoose connect call to rule out connection failures:

  const mongoose = require('mongoose');
  
  mongoose.connect('mongodb://<remote-host>:27017/<your-db-name>', {
    useNewUrlParser: true,
    useUnifiedTopology: true
  })
  .then(() => console.log("Successfully connected to remote MongoDB!"))
  .catch(err => console.error("Connection failed:", err));
  

• Ensure your remote host's firewall allows incoming traffic on MongoDB's default port (27017), and your database user has read/write permissions for your target collection.

2. Fix Incomplete Schema Definition #

Looking at your code snippet, the trackLink field's type is cut off as Str...—make sure this is properly set to String (Mongoose doesn't recognize Str):

var Visits = new Schema({ 
  client: { type: Schema.ObjectId, ref: 'Client', required: true }, 
  sources: Object, 
  landingReached: { type: Boolean, required: true, default: false }, 
  date: { type: Date, required: true, default: new Date() }, 
  trackLink: { type: String } // Complete the type definition
});

Mismatched or invalid field types can cause queries to silently return empty results.

3. Validate Your Query Syntax #

Depending on which property you're querying, make sure your syntax aligns with Mongoose 5.x requirements:

• Querying by client (ObjectId): Don't pass a raw string—convert it to a Mongoose ObjectId first:

  // Wrong: Passing a string directly
  Visits.find({ client: '1234567890abcdef12345678' });
  
  // Right: Converting to ObjectId
  Visits.find({ client: mongoose.Types.ObjectId('1234567890abcdef12345678') });
  

• Querying nested sources object: Use dot notation to target nested properties instead of passing the entire object (unless you need an exact match):

  // Query for visits where sources has a "referrer" property equal to "google"
  Visits.find({ 'sources.referrer': 'google' });
  

• Querying boolean/date fields: Ensure your values match the field type (e.g., true instead of "true" for landingReached, valid Date objects for date).

4. Confirm Model & Collection Alignment #

Mongoose automatically pluralizes model names to map to collections. If you named your model Visits, it will look for a collection named visits (lowercase plural). Double-check that:

• You've properly compiled your Schema into a Model:

  const VisitModel = mongoose.model('Visits', Visits); // Or 'Visit' if your collection is 'visits'
  

• Your remote database actually contains documents in the correct collection (use MongoDB Compass or the mongo shell to verify: db.visits.find()).

5. Check for Mongoose 5.0.11-Specific Quirks #

Version 5.0.11 is a relatively old release of Mongoose 5.x. Consider these:

• If you're using lean() in your queries, ensure it's not interfering with field projection or filtering.
• Some query operators might have had behavior changes in later 5.x versions—try temporarily upgrading to the latest 5.x release (e.g., 5.13.20) to see if the issue resolves.
• Always handle query errors to catch issues like invalid operators:

  VisitModel.find({ landingReached: true })
  .then(results => console.log("Found visits:", results))
  .catch(err => console.error("Query error:", err)); // This will reveal syntax or permission issues
  

6. Verify Document Existence #

Last but not least: make sure the documents you're trying to query actually exist in the remote database. Use the mongo shell or a GUI tool to run the same query directly against MongoDB—if it returns no results, your issue is with data, not your code.

内容的提问来源于stack exchange，提问作者fcshadow