README.md

mongoql

An OTP library to translate a special search query language (including aggregation) in MongoDB query.

Note: the queries are compatible with mongodb-erlang package.

Examples Query

E.g. select data where temperature>23 AND house is in Milano and pression <= 1015, ordered by house name ascending:

house.temperature>23 house.city:"Milano" house.pression<:1015 house.when>2017-12-15T10:20:00Z house.name-asc

Translated in the follow MongoDB query:

Query = {
  '$query', {
    '$and', [
      {<<"house.temperature">>, {'$gt', 23}},
      {<<"house.city">>, {'$eq', <<"Milano">>}},
      {<<"house.pression">>, {'$lte', 1015}},
      {<<"house.when">>, {'$gt', {1513, 333200, 0}}}
    ]
  },
  '$orderby', [
    {<<"house.name">>, 1}
  ]
},
mongopool_app:find(Pool, Table, Query).

Example Aggregation

E.g. count how many times received a new log message today grouped by log level:

date > now-24h date-asc $group id: level count: $count(1)

How to use

Simple query:

MyQueryString = "house.temperature>23 house.city:\"Milano\" house.pression<:1015 house.when>2017-12-15T10:20:00Z house.when < now house.name-asc",
{ok, Query} = mongoql:parse(MyQueryString),
mongopool_app:find(Pool, Table, Query).

Aggregation query:

MyAggString = "date > now-24h date-asc $group id: level count: $count(1)"
{ok, Agg} = mongoql:agg(MyAggString),
mongopool_app:command(Pool, TableInBinaryString, pipeline, Agg).

Operators

Op.	Name	Example
<	Minor	temperature < 10.5
<:	Minor Equal	temperature <: 7.3
:	Equal	temperature : 5 or name : "FuuBar"
>:	Major Equal	temperature >: 2
>	Major	temperature > 4.4
!:	Not Equal	temperature !: 4 or name !: "FuuBar"
~	Regex	name ~ "Mi*"
in	In	temperature in [16 17 18] or city in ["Milano" "Roma"]
not	Not	not temperature > 5 or not name in ["Milano" "Roma"]
exists	Exists*(#)	name exists or not name exists
{name}-asc	Order Ascending	name-asc
{name}-desc	Order Descending	name-desc

(#) matches the documents that contain the field.

Types supported

Type	Example
Integer	15, -23, 543
Float	34.56, -235.32
String	"Hello world!"
Datetime	2016-01-15T18:19:28Z (Note: without doublequote)
Datetime	now (automatically translated with now datetime of the server
Datetime	now - 1h, now - 1m, now - 1s

Build

$ ./utils/rebar3 compile