How to partial update mongodb document in Web Api Patch request

Question

I want to partial update fileds of my document that changed in the patch request and in every request the field probably changed .

Note: there is nothing in IDto interface, I use it just for separating Dtos from other classes.

UpdateAccountDto.cs

public class UpdateAccountDto : IDto
{
    public string Id { get; set; } = string.Empty;
    public string AccountId { get; set; } = string.Empty;

    public string AccountHolder { get; set; } = string.Empty;

    public string AccountType { get; set; } = string.Empty;

    public decimal Balance { get; set; }
}

Account.cs my entity

public class Account
{
    [BsonId]
    [BsonRepresentation(BsonType.ObjectId)]
    public string Id { get; set; } = string.Empty;
    [BsonElement("account_id")] 
    public string AccountId { get; set; } = string.Empty;

    [BsonElement("account_holder")]
    public string AccountHolder { get; set; } = string.Empty;

    [BsonElement("account_type")]
    public string AccountType { get; set; } = string.Empty;
    
    [BsonRepresentation(BsonType.Decimal128)]
    [BsonElement("balance")]
    public decimal Balance { get; set; }

}

My endpoint

        [HttpPatch("UpdatePartialAccount")]
        public async Task<ActionResult> UpdatePartialAccount([FromQuery]string id,[FromBody] JsonPatchDocument<UpdateAccountDto>? document)
        {
            if (document is null)
                return BadRequest();

            var updateAccountDto = document.ToDto();

            document.ApplyTo(updateAccountDto, ModelState);

            if (!ModelState.IsValid)
                return BadRequest();

            var entity = updateAccountDto.ToEntity<Account>();
            entity.Id = id;

            await _accountRepository.PartialUpdateAsync(entity);

            return NoContent();

        }

PartialUpdateAsync method

   public async Task<UpdateResult> PartialUpdateAsync(Account account)
    {
        //var filter = Builders<Account>.Filter.Eq(a => a.Id, account.Id);
        //var update = Builders<Account>.Update.Set()
        //Partial update

        
    }

Answer 1

Your question are actually not very clear, but I guess you may want to know the field settings corresponding to JsonPatchDocument and the operation of updating the Mongodb database.

Regarding the field setting of JsonPatchDocument , you can refer to the official document to use it. For example:

[HttpPatch("UpdatePartialAccount")]
        public async Task<ActionResult> UpdatePartialAccount([FromQuery] string id, [FromBody] JsonPatchDocument<UpdateAccountDto>? document)
{
    if (document is null)
        return BadRequest();

    var dto = new UpdateAccountDto() { AccountId = "DAccount1" };

    document.ApplyTo(dto, ModelState);
    //.....
}

Suppose you do a Replace operation on it:

[
  {
    "operationType": 2,
    "path": "/accountHolder",
    "op": "replace",
    "value": "TestHolder"
  }
]

At this point your dto will become:

Please confirm the content of dto and then match with Account to update the database(I'm not sure how you map to Account , but I used AutoMapper ). For example:

public async Task UpdateAsync(Account account)
{
    await _account.UpdateOneAsync(c => c.AccountId == account.AccountId, account.AccountHolder);
}

For more operations on updating the database, you can check this link .

Hope this can help you.