Query BinData by Type in MongoDB

To query BinData documents by their subtype in MongoDB, use the subtype() method within a JavaScript function to filter documents based on their binary data type.

Syntax

db.collection.find(function(){ 
    return this.fieldName.subtype() == subtypeNumber 
});

Sample Data

Let us create a collection with documents containing different BinData subtypes ?

db.demo249.insertMany([
    { "_id": BinData(0, "AQAAAAEBAAVlbl9VSwAAAAAAAAhv") },
    { "_id": BinData(4, "CNDF66qIlCY92q1vFAAAAQ==") },
    { "_id": BinData(3, "CNDF66qJ29g92q1vFAAAEw==") }
]);

{
    "acknowledged": true,
    "insertedIds": {
        "0": BinData(0, "AQAAAAEBAAVlbl9VSwAAAAAAAAhv"),
        "1": UUID("08d0c5eb-aa88-9426-3dda-ad6f14000001"),
        "2": BinData(3, "CNDF66qJ29g92q1vFAAAEw==")
    }
}

Display all documents from the collection ?

db.demo249.find();

{ "_id": BinData(0, "AQAAAAEBAAVlbl9VSwAAAAAAAAhv") }
{ "_id": UUID("08d0c5eb-aa88-9426-3dda-ad6f14000001") }
{ "_id": BinData(3, "CNDF66qJ29g92q1vFAAAEw==") }

Example: Query BinData by Subtype 0

To find documents with BinData subtype 0 (Generic binary subtype) ?

db.demo249.find(function(){ 
    return this._id.subtype() == 0 
});

{ "_id": BinData(0, "AQAAAAEBAAVlbl9VSwAAAAAAAAhv") }

Key Points

• BinData subtypes: 0 (Generic), 3 (UUID old), 4 (UUID standard), 5 (MD5), etc.
• The subtype() method returns the numeric subtype of the BinData field.
• Use JavaScript functions with find() to filter by subtype values.

Conclusion

Use the subtype() method within JavaScript functions to query MongoDB documents by their BinData subtype. This approach allows filtering binary data based on specific type classifications.