This CorDapp demonstrates how Custom Query works in Corda. Corda allows developers to have the ability to query the vault using multiple mechanisms such as the Vault Query API, using a JDBC session, etc. This sample demonstrates how to store your state data to a custom database using an ORM tool and how to query this vault via Vault Query using some custom field defined in your state (for example a string property of your state). To use Vault Query to query by a certain property the state must implement QueryableState with a custom mapped schema. This way the DB (and Corda) know what you will be querying By. Please refer to the flow InsuranceClaimFlow for details.

In this CorDapp we would use an Insurance state and persist its properties in a custom table in the database. The Insurance state among other fields also contains an VehicleDetail object, which is the asset being insured. We have used this VehicleDetail to demonstrate One-to-One relationship. Similarly, we also have a list of Claim objects in the Insurance state which represents claims made against the insurance. We use them to demonstrate _ One-to-Many_ relationship.

A spring boot client is provided with the CorDapp, which exposes two REST endpoints (see Controller in the clients' module) to trigger the flows. Use the command ./gradlew bootRun in the project root folder to run the Spring Boot Server.

There are two flows in this CorDapp:

1. IssueInsurance: It creates the insurance state with the associated vehicle information.

2. InsuranceClaim: It creates the claims against the insurance.It uses the Vault Query to perform a custom vault query.

For development environment setup, please refer to: Setup Guide.

Open a terminal and go to the project root directory and type: (to deploy the nodes using bootstrapper)

./gradlew clean build deployNodes

Then type: (to run the nodes)

./build/nodes/runnodes

The Postman collection containing API's calls to the REST endpoints can be imported from the link: https://www.getpostman.com/collections/ddc01c13b8ab4b5e853b. Use the option Import > Import from Link option in Postman to import the collection. The collection file is also included in this repo for reference.

The JDBC url to connect to the database would be printed in the console in node startup. Use the url to connect to the database using a suitable client. The default username is 'sa' and password is '' (blank). You could download H2 Console to connect to h2 database here: http://www.h2database.com/html/download.html

Refer here for more details regarding connecting to the node database. https://docs.corda.net/head/node-database-access-h2.html