Intro

This library exports a function getQuery which takes a data-structure as query and returns an Postgres SQL query to retrieve nested data in JSON form.

JSON Query

Here is an example of a JSON query

  {
    "table_name": {
      "fields": {
        "id": "table_id"
      },
      "children": {
        "other_table": {
          "fields": {
            "id": "other_id"
          }
        }
      },
      "conditionString": "example_number = 1",
      "conditions": { "boolean_field": true, "number_field": "> 5" }
    }
  }

Description

table_name - is the name of the table querying

children - is an embedded query neste under the current table

conditions - contains field keys with values that the field should equal. A leading '=' is implied if an operator is not specified.

conditionString - raw unprocessed condition.

Example

import getQuery from 'pg-nested-json-query'

{
const query = {
  "table_name": {
    "fields": {
      "id": "table_id"
    },
    "children": {
      "other_table": {
        "fields": {
          "id": "other_id"
        }
      }
    },
    "conditionString": "example_number = 1",
    "conditions": {
      "boolean_field": true,
      "number_field": "> 5"
    }
  }
}


console.log( getQuery( query ) )

Output

select json_build_object(
  'table_name', array(
    select json_build_object(
      'id', table_name.table_id,
      'other_table', array(
        select json_build_object(
          'id', other_table.other_id
        ) from other_table where other_table.table_id = table_name.table_id
      )
    ) from table_name where table_name.boolean_field = true and table_name.number_field > 5 and example_number = 1
  )
)

CLI Tool

This package provides a CLI in bin directory that can accept either a JSON, JSON6, or YAML file as a query and writes and Postgres SQL query to STDIN.

Example use

npx pg-nested-json-query web-query.yaml | psql database > web-data.json

Here is the help screen for CLI tool

Usage

  pg-nested-json-query query-file [options]

Options

  --file file       This is the default option and can be omitted.
  --type, -t type   Declare file format. Either "yaml", "json" or "json6".
  --help, -h        Opens this help screen, all other options are ignored.

MIT License (As-Is No Warranty Open License)

Copyright 2018 Babak Badaei

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.