Table query

[famence]

Summary:

Adds the ability to table.query() respecting models correctly. Useful for utilising the single table approach when you want to get multiple items of different models within single request.
⚠️ Preferably to be reviewed after #1517 (depends on #1517) as the current one is based on it.

Code sample:

General

Let's assume we have two models Team and TeamMember within single table:

const Team = dynamoose.model("Team", {
  "pk": {
    "type": String,
    "index": {
      "hashKey": true,
      "index": {
        "name": "primary",
        "type": "global"
      }
    },
    "map": "id"
  },
  "sk": {
    "type": String,
    "rangeKey": true
  },
  "name": String,
  "type": {"type": String, "default": "team"}
});
const TeamMember = dynamoose.model("TeamMember", {
  "pk": {
    "type": String,
    "index": {
      "hashKey": true,
      "index": {
        "name": "primary",
        "type": "global"
      }
    },
    "map": "teamId"
  },
  "sk": {
    "type": String,
    "rangeKey": true,
    "map": "id"
  },
  "name": String,
  "type": {"type": String, "default": "member"}
});
const table = new dynamoose.Table("teams", [Team, TeamMember]);

and some instances of each type:

const team1 = new Team({"id": "team_1", "name": "Team 1"});
const member1 = new TeamMember({"teamId": "team_1", "id": "member_1", "name": "Team member 1"});

now we can query the table for any global index (i.e. primary key) and get relevant items with correct models mapping:

await table.query({"pk": "team_1"}).exec()
// will return the following:
[
  Team {
    id: 'team_1',
    sk: '',
    name: 'Team 1',
    type: 'team'
  },
  TeamMember {
    teamId: 'team_1',
    id: 'member_1',
    name: 'Team member 1',
    type: 'member'
  },
]

The models of each item are identified correctly and all the attributes are mapped as we expect in our schemas.

The magic is in respecting attributes' default values which add +2 score weight and in improved Model.schemaCorrectnessScores method by adding up the scores to determine the most suitable model even if the models' schemas are same except default values.

Type (select 1):

• Bug fix
• Feature implementation
• Documentation improvement
• Testing improvement

• Test added to report bug (GitHub issue #---- @---)
• Something not listed here

Is this a breaking change? (select 1):

• 🚨 YES 🚨
• No
• I'm not sure

Is this ready to be merged into Dynamoose? (select 1):

• Yes
• No

Are all the tests currently passing on this PR? (select 1):

• Yes
• No

Other:

• I have read through and followed the Contributing Guidelines
• I have searched through the GitHub pull requests to ensure this PR has not already been submitted
• I have updated the Dynamoose documentation (if required) given the changes I made
• I have added/updated the Dynamoose test cases (if required) given the changes I made
• I agree that all changes made in this pull request may be distributed and are made available in accordance with the Dynamoose license
• All of my commits and commit messages are detailed, explain what changes were made, and are easy to follow and understand
• I have filled out all fields above

[github-actions]

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[fishcharlie]

@famence #1517 has been merged. Do you maybe want to merge develop into this branch and finalize anything else and mark it ready for review and I can take a look at it?

[famence]

@fishcharlie i just finished the technical part so you are welcome to review the code

[famence]

Documentation updated

[marcofailache]

Hey, guys! Thanks for the hard work!
Any timeframe for when this pull request will be merged?