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https://github.com/thomas4019/mongo-query-to-postgres-jsonb
Converts MongoDB queries to postgresql queries for jsonb fields.
https://github.com/thomas4019/mongo-query-to-postgres-jsonb
Last synced: 8 days ago
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Converts MongoDB queries to postgresql queries for jsonb fields.
- Host: GitHub
- URL: https://github.com/thomas4019/mongo-query-to-postgres-jsonb
- Owner: thomas4019
- License: mit
- Created: 2016-05-02T23:01:08.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2024-08-24T22:43:04.000Z (3 months ago)
- Last Synced: 2024-10-30T08:19:32.432Z (14 days ago)
- Language: JavaScript
- Size: 343 KB
- Stars: 109
- Watchers: 7
- Forks: 14
- Open Issues: 12
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Mongo-Postgres Query Converter
[MongoDB query documents](https://docs.mongodb.org/manual/tutorial/query-documents/) are quite powerful.
This brings that usefulness to PostgreSQL by letting you query in a similar way.
This tool converts a Mongo query to a PostgreSQL `where` clause for data stored in a jsonb field.
It also has additional converters for Mongo projections which are like `select` clauses and for `update` queries.
This tool is used by [pgmongo](https://github.com/thomas4019/pgmongo) which intends to provide a drop-in replacement for MongoDB.
## Installation
```sh
npm install mongo-query-to-postgres-jsonb
```
## Simple Usage
```js
var mToPsql = require('mongo-query-to-postgres-jsonb')
var query = { field: 'value' }
var sqlQuery = mToPsql('data', query)
```
## API
```js
var mToPsql = require('mongo-query-to-postgres-jsonb')
```
### mToPsql(sqlField, mongoQuery, [arrayFields])
#### sqlField
This is the name of your jsonb column in your postgres table which holds all the data.
#### mongoQuery
An object containing MongoDB [query operators](https://docs.mongodb.com/manual/reference/operator/query/).
#### arrayFields
This tool doesn't know which fields are arrays so you can optionally specify a list of dotted paths which should be treated as an array.
### mToPsql.convertSelect(sqlField, projectionQuery, [arrayFields])
#### projectionQuery
Object specifying which a subset of documents to return. Note: advanced [projection fields](https://docs.mongodb.com/manual/reference/operator/projection/) are not yet supported.
### mToPsql.convertUpdate(sqlField, updateQuery, [upsert])
#### updateQuery
Object containing [MongoDB operations](https://docs.mongodb.com/manual/reference/operator/update/) to apply to the documents.
#### upsert
Indicate that the query is being used for upserting. This will create a safer query that works if the original document doesn't already exist.
### mToPsql.convertSort(sqlField, sortQuery, [forceNumericSort])
#### sortQuery
Object containing [desired ordering](https://docs.mongodb.com/manual/reference/method/cursor.sort/#sort-asc-desc)
#### forceNumericSort
Cast strings to number when sorting.
## Examples
| Languages | MongoDB | Postgres |
|------------|-------------------------------|---------------------------------------------------------------------------------|
| Where | { 'names.0': 'thomas' } | (data->'names'->>0 = 'thomas') |
| Where | { 'address.city': 'provo' } | data @> { "address": '{ "city": "provo" }' } |
| Where | { $or: [ { qty: { $gt: 100 } }, { price: { $lt: 9.95 } } ] } | ((data->'qty'>'100'::jsonb) OR (data->'price'<'9.95'::jsonb)) |
| Projection | { field: 1 } | jsonb_build_object('field', data->'field', '_id', data->'_id')' |
| Update | { $set: { active: true } } | jsonb_set(data,'{active}','true'::jsonb) |
| Update | { $inc: { purchases: 2 } } | jsonb_set(data,'{purchases}',to_jsonb(Cast(data->>'purchases' as numeric)+2)) |
| Sort | { age: -1, 'first.name': 1} | data->'age' DESC, data->'first'->'name' ASC |
## Advanced Select: Match a Field Without Specifying Array Index
* [Mongo Docs](https://docs.mongodb.org/manual/tutorial/query-documents/#match-a-field-without-specifying-array-index)
With MongoDB, you can search a document with a subarray of objects that you want to match when any one of the elements in the array matches.
This tool implements it in SQL using a subquery, so it will likely not be the efficient on large datasets.
To enable subfield matching, you can pass a third parameter which is either an array of dotted paths that will be assumed
to potentially be arrays or `true` if you want it to assume any field can be an array.
Example document:
```js
{
"courses": [{
"distance": "5K"
}, {
"distance": "10K"
}]
]
```
Example queries to match:
```js
mongoToPostgres('data', { 'courses.distance': '5K' }, ['courses'])
mongoToPostgres('data', { 'courses.distance': '5K' }, true)
```
This then creates a PostgreSQL query like the following:
```
(data->'courses'->>'distance'='5K'
OR EXISTS (SELECT * FROM jsonb_array_elements(data->'courses')
WHERE jsonb_typeof(data->'courses')='array' AND value->>'distance'='5K'))
```
Note: nested paths are not yet supported, so passing ['courses', 'courses.distance'] won't support checking both.
The first matching path is the one that will be used.
## Supported Features
* $eq, $gt, $gte, $lt, $lte, $ne
* $or, $not, [$in](https://docs.mongodb.org/manual/reference/operator/query/in/#use-the-in-operator-to-match-values-in-an-array), $nin
* $elemMatch
* [$regex](https://docs.mongodb.com/manual/reference/operator/query/regex/), [$type](https://docs.mongodb.org/manual/reference/operator/query/type/#op._S_type), [$size](https://docs.mongodb.org/manual/reference/operator/query/size/#op._S_size), [$exists](https://docs.mongodb.org/manual/reference/operator/query/exists/#op._S_exists), [$mod](https://docs.mongodb.com/manual/reference/operator/query/mod/), [$all](https://docs.mongodb.com/manual/reference/operator/query/all/)
## Todo
* Filtering
* [$expr](https://docs.mongodb.com/manual/reference/operator/query/expr/)
* [Bitwise Operators](https://docs.mongodb.com/manual/reference/operator/query-bitwise/)
* Update
* [$pop](https://docs.mongodb.com/manual/reference/operator/update/pop/)
* [$currentDate](https://docs.mongodb.com/manual/reference/operator/update/currentDate/)
* [$setOnInsert](https://docs.mongodb.com/manual/reference/operator/update/setOnInsert/)
## Cannot Support
* [$where](https://docs.mongodb.com/manual/reference/operator/query/where/)
## See also
* [PostgreSQL json/jsonb functions and operators](http://www.postgresql.org/docs/9.4/static/functions-json.html)
* [PostgreSQL json documentation](http://www.postgresql.org/docs/9.4/static/datatype-json.html)
* [MongoDB query documention](https://docs.mongodb.org/manual/tutorial/query-documents/)
* [PostgreSQL Array Functions](https://www.postgresql.org/docs/9.3/static/functions-array.html)
* [JSON array to PostgreSQL Array](https://dba.stackexchange.com/questions/54283/how-to-turn-json-array-into-postgres-array/54289#54289)