Why is My '_id' Value Returning an Empty String When Using Golang's MGO?

Trouble Retrieving "_id" Value Using Golang's MGO

In an attempt to retrieve "_id" values from a MongoDB database using the MGO package in Golang, users may encounter a frustrating issue where the "_id" field consistently returns an empty string. This perplexing behavior can impede further data processing and manipulation.

To investigate the root cause of this issue, we delve into the provided code structure. The struct definition for the Article object appears to be constructed correctly, with the "_id" field annotated using both "bson" and "json" tags.

Next, we examine the method used to extract data from the database, which utilizes the Find and All functions from the "c_articles" collection. This method returns an array of Article objects, and it's here that we encounter the discrepancy.

By inspecting the sample object stored in the database, we observe that the "_id" field is stored as an ObjectId object. However, when printing the retrieved Article objects, the "Id" field consistently yields an empty string.

Further inspection reveals a subtle error in the code. In the struct definition, a tab character (instead of a space) is used between the "json" and "bson" tags for the "Id" field. Correcting this typo to use a single space effectively separates the two tags, allowing MGO to properly interpret the "_id" field.

Once this modification is implemented, rerunning the code produces the expected results, successfully retrieving the actual "_id" values from the database. This resolution demonstrates the importance of adhering to naming conventions and proper syntax when working with MongoDB and MGO.

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