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Create a Collection

The zkDatabase library provides the functionality to create a collection, which serves as a structured grouping of documents similar to a table in a relational database. In a zkDatabase, each collection is defined by a schema that allows the representation of data both as human-readable JSON and in a cryptographically provable format suitable for zero-knowledge (ZK) circuits. This dual representation ensures data is both easily manageable and secure, supporting advanced privacy-preserving operations.

Definition​

When creating a collection, you need to specify a schema that dictates the structure and data types of the documents. This schema ensures that all documents within the collection are consistent and integrate seamlessly with cryptographic operations.

await zkdb.db(databaseName: string)
    .collection(collectionName: string)
    .create(
      schemaDefinition:Schema,
      permission: Permission,
      groupName: string
    )

Parameters​

  • schemaDefinition (Schema): The predefined structure for the collection, detailing the data types and constraints for its documents, ensuring they meet both usability and cryptographic integrity standards.
  • permission (Permission): A object that defines the permissions for accessing and manipulating the collection, ensuring proper security measures are met.
  • groupName (string): The name of the group associated with this collection. It helps categorize or restrict collections to specific groups of users, supporting both organizational needs and security policies.

Returns​

The operation to create a collection will typically return a promise that resolves upon successful establishment of the collection with its specified schema. This confirmation allows for subsequent operations, such as document insertion and queries.

Example​

Here is an example of creating a collection in the zkDatabase:

import { CircuitString, UInt64 } from 'o1js';
import { Schema, ZkDatabase } from 'zkdb';

const zkdb = await ZkDatabase.connect({
  userName: "chiro-user",
  privateKey: "EKFTciRxyxshZjimay9sktsn7v5PvmC5zPq7q4JnitHUytxUVnFP",
  environment: "node",
  // This URL is for test environment
  url: "https://api.zkdatabase.org/graphql",
});

await zkdb.auth.signIn();

//Create new group for user chiro-user
await zkdb.db('zkdb_test').group('chiro').create({
  groupDescription: 'Test group',
});

// Define the schema for given collection
class Shirt extends Schema.create({
  name: CircuitString,
  price: UInt64,
}) {}

// Create a new collection with the defined schema
console.log(
  await zkdb.db('zkdb_test')
    .collection('test_collection')
    .create(
      Shirt,
      Permission.policyPrivate(),
      'chiro'
    )
);

console.log(await zkdb.db('zkdb_test').collection('test').create(Shirt));

await zkdb.auth.signOut();

Deploy Smart Contract​

To incorporate this collection into a blockchain-based application, you may need to use the zkDatabase Management tool to deploy the appropriate smart contract. This enables on-chain management of the collection, ensuring data integrity and supporting zero-knowledge proofs.