Use Struct Tags

Example

The following code declares a struct of type BlogPost. This struct contains a struct tag that maps the WordCount field to the BSON field name word_count. By default, the driver marshals the other fields as the lowercase of the struct field name:

type BlogPost struct {
	Title       string
	Author      string
	WordCount   int `bson:"word_count"`
	LastUpdated time.Time
	Tags        []string
}

The following example creates a BlogPost instance and inserts it into the posts collection. During the insert operation, the driver interprets the struct tag to marshal the WordCount struct field as word_count:

coll := client.Database("sample_training").Collection("posts")
post := BlogPost{
	Title:       "Annuals vs. Perennials?",
	Author:      "Sam Lee",
	WordCount:   682,
	LastUpdated: time.Now(),
	Tags:        []string{"seasons", "gardening", "flower"},
}
// Inserts a document describing a blog post into the collection
_, err = coll.InsertOne(context.TODO(), post)
if err != nil {
	panic(err)
}

View a fully runnable example.

Expected Result

After you run the full example, you can find the following document in the posts collection:

{
    "_id" : ObjectId("..."),
    "title" : "Annuals vs. Perennials?",
    "author" : "Sam Lee",
    "word_count" : 682,
    "lastupdated": ...,
    "tags" : ["seasons", "gardening", "flower"]
}

For an example on how to find a document, see the Find Documents guide.

Additional Information

To learn more about using struct tags, converting to/from BSON, and handling potential errors, see the Work with BSON guide.