Search array of objects in a MongoDB collection?

To search array of objects in MongoDB, use the find() method with dot notation to target specific fields within array elements. The find() method selects documents in a collection and returns a cursor to the matched documents.

Syntax

db.collection.find({
    "arrayField.objectProperty": "value"
});

// Multiple conditions with $or
db.collection.find({
    $or: [
        {"arrayField.property1": "value1", "arrayField.property2": "value2"},
        {"arrayField.property1": "value3", "arrayField.property2": "value4"}
    ]
});

Sample Data

Let us create a collection with documents containing arrays of objects ?

db.demo484.insertMany([
    { 
        "id": 1, 
        "details": [ 
            { "Name1": "Chris" }, 
            { "Name2": "David" }, 
            { "Name3": "Bob" } 
        ] 
    },
    { 
        "id": 2, 
        "details": [ 
            { "Name1": "Chris" }, 
            { "Name2": "Carol" }, 
            { "Name3": "Bob" } 
        ] 
    },
    { 
        "id": 3, 
        "details": [ 
            { "Name1": "Chris" }, 
            { "Name2": "Carol" }, 
            { "Name3": "Mike" } 
        ] 
    }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e82e3a4b0f3fa88e22790a1"),
        ObjectId("5e82e3a4b0f3fa88e22790a2"),
        ObjectId("5e82e3a4b0f3fa88e22790a3")
    ]
}

Display all documents from the collection ?

db.demo484.find();

{ "_id": ObjectId("5e82e3a4b0f3fa88e22790a1"), "id": 1, "details": [ { "Name1": "Chris" }, { "Name2": "David" }, { "Name3": "Bob" } ] }
{ "_id": ObjectId("5e82e3a4b0f3fa88e22790a2"), "id": 2, "details": [ { "Name1": "Chris" }, { "Name2": "Carol" }, { "Name3": "Bob" } ] }
{ "_id": ObjectId("5e82e3a4b0f3fa88e22790a3"), "id": 3, "details": [ { "Name1": "Chris" }, { "Name2": "Carol" }, { "Name3": "Mike" } ] }

Example: Search Array Objects with Multiple Conditions

Find documents where Name2 is "Carol" and Name3 is either "Mike" or "Bob" ?

db.demo484.find({
    $or: [
        {"details.Name2": "Carol", "details.Name3": "Mike"},
        {"details.Name2": "Carol", "details.Name3": "Bob"}
    ]
});

{ "_id": ObjectId("5e82e3a4b0f3fa88e22790a2"), "id": 2, "details": [ { "Name1": "Chris" }, { "Name2": "Carol" }, { "Name3": "Bob" } ] }
{ "_id": ObjectId("5e82e3a4b0f3fa88e22790a3"), "id": 3, "details": [ { "Name1": "Chris" }, { "Name2": "Carol" }, { "Name3": "Mike" } ] }

Key Points

• Use dot notation (arrayField.objectProperty) to search within array objects.
• MongoDB searches across all array elements automatically.
• Use $or for multiple condition combinations.

Conclusion

Search arrays of objects using dot notation to target specific properties within array elements. Combine multiple conditions with $or operator for flexible queries across array object fields.