What

This directory contains the mongodb schema for every database that cadence owns. The directory structure is as follows

./schema
   - cadence/               -- Contains schema for default data models
        - schema.json       -- Contains the latest & greatest snapshot of the schema for the keyspace
        - schema.go         -- Contains the collection schema in Golang structs -- because MongoDB collection is shemaless.  
        - versioned
             - v0.1/
             - v0.2/        -- One directory per schema version change
             - v1.0/
                - manifest.json    -- json file describing the change
                - changes.json     -- changes in this version, only [create collection/index/documents] commands are allowed

MongoDB JSON schema format

Below is an example of a schema JSON file containing two commands, for collection/index/documents creation.

[
  {
    "create": "collection_name"
  },
  {
    "createIndexes": "collection_name",
    "indexes": [
      {
        "key": {
          "fieldnamea": 1,
          "fieldnameb": -1
        },
        "name": "fieldnamea_fieldnameb"
      }
    ],
    "writeConcern": { "w": "majority" }
  },
  {
    "insert": "collection_name",
    "documents": [
      {
        "fieldnamea": 1,
        "fieldnameb": 0,
        "fieldnamec": "1234"
      },
      {
        "fieldnamea": 2,
        "fieldnameb": 1,
        "fieldnamec": "12344"
      },
      {
        "fieldnamea": 2,
        "fieldnameb": 2,
        "fieldnamec": "12345"
      }
    ],
    "ordered": false
  }
]

How

Q: How do I update existing schema ?

• Add your changes to schema.json for snapshot
• Create a new schema version directory under ./schema/<>/versioned/vx.x
  • Add a manifest.json
  • Add your changes in a json file