https://github.com/thomas4019/pgmongo

Replace MongoDB with PostgreSQL using jsonb fields
https://github.com/thomas4019/pgmongo

Last synced: 3 days ago
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Replace MongoDB with PostgreSQL using jsonb fields

• Host: GitHub
• URL: https://github.com/thomas4019/pgmongo
• Owner: thomas4019
• Created: 2018-05-31T06:39:14.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-12-23T08:25:30.000Z (almost 6 years ago)
• Last Synced: 2024-11-09T13:42:32.587Z (4 days ago)
• Language: JavaScript
• Homepage:
• Size: 40 KB
• Stars: 133
• Watchers: 9
• Forks: 7
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        


  

  
Replace MongoDB with PosgreSQL


## What is pgmongo?

- **Drop-in replacement** Applications do not need code changes. pgmongo appears to your app as a MongoDB server.

- **Stateless proxy** pgmongo rewrites queries and proxies them to a Postgres database.

- **JSON** Primarily supports regular JSON data. Advanced BSON types like binary data, JavaSrcipt, ints and timestamps are not well supported.

This implements the [MongoDB wire protocol](https://docs.mongodb.com/manual/reference/mongodb-wire-protocol/) and adapts queries to work with a PostgreSQL database using jsonb fields.

I've tested it with [Keystone.js](http://keystonejs.com/) and it seemed to work reasonably well.



  



## Getting Started

pgmongo requires node 8 or newer and Postgres 9.4+. Then run the following.

```bash

npm install -g pgmongo

pgmongo

```

This will start a mongo-like server on port 27017. If you already have mongo running on your machine you can start it on a different port with the following.

```bash

pgmongo localhost 27018

```

## Supported Features

* listing/creating/dropping collections

* find (including sorting, skip and offset)

* count, distinct

* update (including support for upserting)

* insert (including batch insertion)

* deletion

* creating and listing basic indexes

* most custom parameters like $gt, $exists, $regex, $push, $set, $unset, etc.

See [this repo](https://github.com/thomas4019/mongo-query-to-postgres-jsonb)  for the full list

* admin commands (returns mostly stubbed/fake data)

# Current status

It's not production ready yet, but definitely working enough to play around with or use in basic apps.  

Currently passes 190 of the 916 core mongo [jstests](https://github.com/mongodb/mongo/tree/master/jstests/core).

## Example Query Conversions

```

db.createCollection('users')  ->  CREATE TABLE IF NOT EXISTS "users" (data jsonb)

db.users.find({ lastLogin: { $lte: '2016' } })  ->  SELECT data FROM "users" WHERE data->>'lastLogin'<='2016'

db.users.update({}, { $set: { active: true } })  ->  UPDATE "users" SET data = jsonb_set(data,'{active}','true'::jsonb)

db.users.find({}, { firstName: 1 } )  ->  SELECT jsonb_build_object('firstName', data->'firstName', '_id', data->'_id') as data FROM "users"

db.blogs.insert({ title: 'first post', comments: [] })  ->  INSERT INTO "blogs" VALUES ('{"_id":"5b45b641eb4bd93896d57888","title":"first post","comments":[]}'::jsonb)

db.blogs.remove({ 'state.trash': true })  ->  DELETE FROM "blogs" WHERE data->'state'->'trash'='true'::jsonb

```

## Missing Features / Roadmap (ordered by priority)

Note: contributions/PRs are very much welcome.

* Support for findandmodify

* Better for queries matching array elements

* Preserve BSON (Dates, ObjectIDs, other than _id)

* Cursors (currently all data is returned in first result)

* Better Indexes support (not sure if compound indexes are possible)

* [min](https://docs.mongodb.com/manual/reference/method/cursor.min/) and max

* Support numeric object keys (currently numbers are assumed to be an array index)

* Capped collections

* geo support

* explain queries

* aggregation framework/map reduce queries

### Likely Cannot support

* NaN and Infinity

* Preserve the initial order of object keys

* $eval and $where

## Resources

* [mongo-query-to-postgres-jsonb](https://github.com/thomas4019/mongo-query-to-postgres-jsonb) (heavily used as a dependency)

* [Mongo Admin Commands](https://docs.mongodb.com/manual/reference/command/nav-administration/)

* [JSONB Index Performance](http://bitnine.net/blog-postgresql/postgresql-internals-jsonb-type-and-its-indexes/)

## Want to contribute?

Anyone can help make this project better. Feel free to open an issue to discuss what you want to work on.

## Related Projects

[Mongres](https://github.com/umitanuki/mongres),

[mongolike](https://github.com/JerrySievert/mongolike),

[plv8](https://github.com/plv8/plv8),

[ToroDB](https://news.ycombinator.com/item?id=8527013)