[FEATURE] v3 single table attribute mapping

Summary:

I’m using the alpha of v3 to build out a single table design using multiple models each with their own schema. As a result of this single table design I’m using generic attributes (pk, sk, etc.) to store different things depending on the model. The problem is that you lose the meaning of these values on the different models.

Is there any plan to introduce a mapping of model attributes to underlying table attributes?

Example

const userSchema = new dynamoose.Schema({
    "id": {
       type: String,
       map: "pk"
     }
    "type": {
       type: String,
       map: "sk"
     }
});

const orderSchema = new dynamoose.Schema({
    "userId": {
       type: String,
       map: "pk"
     }
    "orderId": {
       type: String,
       map: "sk"
     }
});

[fishcharlie]

@alexedwardjones Nope, no plans until you created this issue 😉. Love this idea tho. I will prioritize it for v3. Really appreciate the feedback and feature suggestion.

Also, thank you for trying v3. Any feedback (good or bad) is appreciated. Even good feedback tells us that we are almost ready to ship. So really appreciate it. Feel free to continue to create issues or contact me with any other feedback.

Thanks again!

[fishcharlie]

@AlisonVilela

I wonder if it would be possible to add prefix too?

How would this work? Would it just prefix all values with a certain prefix string? How would this work on reads from DynamoDB? Or would it only apply to saves? How about a prefix on a key property and you get using that property? Would the value you get on be prefixed with that value before running the query?

Something similar that you might want to look into is the set function: https://beta.dynamoosejs.com/guide/Schema#set-function--async-function. This would allow you to set a function that gets run whenever saving an item to DynamoDB, and also when retrieving an item with that property as part of the query. I think that might meet your needs here.

and maybe a way to add multiple PK and SK

I don’t understand what you mean here. In DynamoDB you can only have one primary key, and one sort key. You can’t have multiple of both. Just not allowed in DynamoDB.

If you are wanting to combine two attributes that you have into a single PK or SK attribute, that can be easily achieved using the combine type in Dynamoose: https://beta.dynamoosejs.com/guide/Schema#attribute-types. However, it is important to note that the underlying values will also be stored as part of your item.

For example, lets say you had a raceId property, and a partId property. And you want your PK to be the values of both of those properties, separated by a -. You could use the Combine type on your PK property, and have it combine the raceId and partId values automatically for you. But the underlying item will still include the raceId and partId values as different attributes.

Using the Schema’s Parent would work similar?

Apologies, but I don’t understand what you mean here at all.

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Hopefully this answers your questions.