I want to get the entire list_atttributes field from my mongo document:

db.config.find({},{list_attributes:1, _id:0});
[
{
    list_attributes: {
    '0': { field: 'LASTNAME', field_key: 'lastname', dataType: 'text' },
    '1': { field: 'FIRSTNAME', field_key: 'firstname', dataType: 'text' },
    '2': { field: 'SMS', dataType: 'text' },
    '3': {
        field: 'DOUBLE_OPT-IN',
        dataType: 'category',
        order: 1,
        catAttrib: { '1': 'Yes', '2': 'No' }
    },
    '4': { field: 'OPT_IN', dataType: 'boolean', order: 2 },
    '5': { field: 'TEST_NUMBER', dataType: 'float', order: 3 },
    '6': { field: 'TEST_DATE', dataType: 'date', order: 4 }
    }
}
]

I tried to write it like this:

filter := options.Find().SetProjection(bson.M{"list_attributes": 1})

// Pass the filter to Find() to return a MongoDB cursor
cursor, err := col.Find(ctx, filter)
if err != nil {
    log.Fatal("col.Find ERROR:", err)
}

But the cursor returns 0 results here.

How do I create a bson.M filter for the same projection?

I am using the official mongodb drive for go.

CodePudding user response：

Something like this should work

import (
    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
)

func find(ctx context.Context) error {
    // ...
    cursor, err := collection.Find(ctx, bson.M{}, options.Find().SetProjection(bson.M{"list_attributes": 1}))
    if err != nil {
        return err
    }
    // ...
    return nil
}