Configuration Reference

Introduction

The configuration is a metadata object that lists all the database entities — such as collections and fields — that the data connector has to know about in order to serve queries. It never changes during the lifetime of the data connector service instance. When your database schema changes you will have to update the configuration accordingly, see updating with introspection.

Structure

The configuration object is a JSON object with the following fields:

{
  "config": {
    "collection_names": [],
    "object_fields": {},
    "object_types": {}
  }
}

Property: Collection Names

This is an array of collection (table) names that are included in the configuration. This is a required field.

Example:

{
  "collection_names": ["users", "posts"]
}

Property: Object Fields

This is a JSON object containing metadata about each collection's fields, including data types, primary keys, nullable fields, and foreign key relationships.

Example for a single collection:

{
  "users": {
    "field_names": ["id", "name", "age"],
    "field_types": {
      "id": "Int",
      "name": "String",
      "age": "Int"
    },
    "primary_keys": ["id"],
    "unique_keys": [],
    "nullable_keys": [],
    "foreign_keys": {}
  }
}

Each collection entry contains:

• field_names: Array of column names in the collection
• field_types: Mapping of field names to their data types
• primary_keys: Array of field names that form the primary key
• unique_keys: Array of field names with unique constraints
• nullable_keys: Array of field names that can be null
• foreign_keys: Object mapping fields to their foreign key relationships

Foreign key example:

{
  "foreign_keys": {
    "user_id": {
      "table": "users",
      "column": "id"
    }
  }
}

Property: Object Types

This provides detailed type information for each field in each collection, including handling of nullable fields.

Example:

{
  "users": {
    "fields": {
      "id": {
        "type": {
          "type": "named",
          "name": "Int"
        }
      },
      "name": {
        "type": {
          "type": "named",
          "name": "String"
        }
      }
    }
  }
}

For nullable fields, the type is wrapped in a nullable type descriptor:

{
  "created_at": {
    "type": {
      "type": "nullable",
      "underlying_type": {
        "type": "named",
        "name": "String"
      }
    }
  }
}

Updating with introspection

Whenever the schema of your database changes you will need to update your data connector configuration accordingly to reflect those changes.

Running update in a configuration directory will do the following:

• Connect to the database and refresh the collection metadata
• Update the collection_names, object_fields, and object_types to reflect the current database schema
• Preserve any custom configuration that doesn't conflict with the updated schema