README.md

Simplified GraphQL Example

This folder contains the code necessary to run GraphQL queries from within an Oracle Database Free instance. It extends an earlier example using the GraphQL Reference implementation to perform GraphQL queries. Please refer to the blog post for further details.

Version

The code was tested using the following components:

• Oracle Database 23ai (Free) on Linux x86-64 (version 23.6)
• Node v20 (LTS "Iron")
• Node packages as per package.json

If you detect problems with the code, kindly file an issue. You may also have to update the software releases, this code acts as an example and isn't maintained on a regular basis.

Using GraphQL in Oracle Database Free

After cloning this directory you need to install the NPM modules first, using npm install. The next step is to create the bundle.js file. This is a job for Rollup. Create the bundle.js like so:

npx rollup -c

The resulting dist/bundle.js file can be loaded into the Oracle Database Free instance as GRAPHQL_ENDPOINT_MODULE. Use a recent SQLcl version to do so. Provided you used the compose file shippping with this repo you can connect to the database using the demouser account and load the module:

./sql demouser@localhost/freepdb1

[enter password when prompted]

SQL> mle create-module -filename dist/bundle.js -module-name GRAPHQL_ENDPOINT_MODULE -version 250206

Once the module is present, expose the GraphQL query to SQL and PL/SQL as follows:

create or replace function graphql_query(
  p_query varchar2,
  p_args json
) return json
as mle module GRAPHQL_ENDPOINT_MODULE
signature 'graphQLQuery';
/

Finally, query the endpoint, for example:

select
  json_serialize(
    graphql_query(
      'query locById($id: Int) { getLocationById(id: $id) { city country_id } }',
      JSON('{id: 1000}')
    )
    pretty
  ) graphql_result
/
 
GRAPHQL_RESULT
--------------------------------------------------------------------------------
{
  "data" :
  {
    "getLocationByID" :
    {
      "city" : "Roma",
      "country_id" : "IT"
    }
  }
}

select
  json_serialize(
    graphql_query(
      'query { getAllLocations { city country_id } }',
      JSON('{id: 1000}')
    )
    pretty
  ) graphql_result
/

GRAPHQL_RESULT
--------------------------------------------------------------------------------
{
  "data" :
  {
    "getAllLocations" :
    [
      {
        "city" : "Roma",
        "country_id" : "IT"
      },
[ ... output removed for clarity ... ]
      {
        "city" : "Mexico City",
        "country_id" : "MX"
      }
    ]
  }
}

select
  json_serialize(
    graphql_query(
      'query locByCity($city: String) { getLocation(city: $city) { city country_id state_province } }',
      JSON('{city: "Utrecht"}')
    )
    pretty
  ) graphql_result
/

GRAPHQL_RESULT
--------------------------------------------------------------------------------
{
  "data" :
  {
    "getLocation" :
    [
      {
        "city" : "Utrecht",
        "country_id" : "NL",
        "state_province" : "Utrecht"
      }
    ]
  }
}