Exporting Facts

To gain more control over the facts in a replica, Jinaga provides mechanisms for exporting facts as files. This allows you to back up your data, analyze it, or move it to other replicas.

Backup: Regularly exporting facts can help you create backups of your data, ensuring that you have a copy in case of data loss or corruption.
Analysis: Exporting facts allows you to analyze your data using external tools, such as data visualization or statistical analysis software.
Migration: If you need to move your data to a different replica, you can export facts from one replica and import them into another.

Exporting from Different Databases

Facts can be exported from different types of databases used by Jinaga:

Postgres Database: If you are using a Jinaga replicator with a Postgres database, you can export facts using the jinaga-export-postgres command-line tool.
SQLite Database: In a MAUI application, facts are stored in an SQLite database. You can export facts using the ExportFactsToJson and ExportFactsToFactual methods provided by the Jinaga library.

In the following sections, we will provide detailed instructions on how to export facts from these different databases.

JSON File Format

The JSON file format is used to export facts in a structured JSON format. This format is useful for data interchange and analysis using JSON-compatible tools.

Example JSON Structure

[
  {
    "hash": "SV3Yseb0FJ/uQoL4IelHHbo1g4PZjnP4bx+aivMiiCkSTn2vSaNR6314KXL+PgO9lX9jmJzWoZABTRHjiFHWdQ==",
    "type": "Blog.Post",
    "predecessors": {
      "site": {
        "hash": "abc123",
        "type": "Blog.Site"
      }
    },
    "fields": {
      "createdAt": "2023-04-28T23:53:00Z"
    }
  }
]

JSON Fields

hash: A unique identifier for the fact
type: The type of the fact
predecessors: An object containing references to predecessor facts
- Each key in the object may contain either a single predecessor or an array of multiple predecessors
fields: An object containing the fact's data fields

Factual File Format

The Factual file format is used to export facts in a JavaScript-like fact declaration format. This format is useful for importing facts back into a Jinaga application or for sharing facts with other Jinaga users.

Example Factual Structure

let f1: Blog.Site = {
    domain: "example.com"
}

let f2: Blog.Post = {
    createdAt: "2023-05-20T10:30:00Z",
    site: f1
}

let f3: Blog.Post.Title = {
    post: f2,
    value: "My First Blog Post",
    prior: []
}

Factual Fields

<fact_id>: A unique identifier for the fact
<fact_type>: The type of the fact
<field_key> and <field_value>: The fact's data fields
<predecessor_key> and <predecessor_fact_id>: References to single predecessor facts
<predecessor_array_key>: References to arrays of predecessor facts