Cbonif/single-table-design

[chrisbonifacio]

Description of changes:

Adds page that goes over single table design in DynamoDB with an Amplify Gen 2 schema example and code snippets

Related GitHub issue #, if available:

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• [ ] amplify-ui
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  ref: MDX: [link](https://docs.amplify.aws/) HTML: <a href="https://docs.amplify.aws/">link</a>

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[printSamuel]

Past me (1 week ago) would have loved this! I'm not sure if this is an officially supported feature, but I think it would be interesting to learn how to use functions like begins_with, greater_than, and between on the sort key. It works with the "old schema", like this:

export function request(ctx) {
  return {
    version: '2017-02-28',
    operation: 'Query',
    query: {
      expression: 'PK = :PK and begins_with(SK, :SK)',
      expressionValues: util.dynamodb.toMapValues({
        ':PK': ctx.arguments.PK,
        ':SK': ctx.arguments.SK
      }),
    },
  };
}

Thanks for your effort. :)