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Collection Management

Check if a Collection Exists​

The exist method checks whether a given collection exists in the specified database.

Definition​

await zkdb.db(databaseName: string)
          .collection(collectionName: string)
          .exist(): Promise<boolean>;

Parameters​

  • None

Returns​

  • Promise<boolean>: Returns true if the collection exists in the database, false if it doesn't exist. This is useful for conditional collection creation, validation checks, and preventing errors when attempting operations on non-existent collections.

Example​

import { 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();

const dbTest = zkdb.db('zkdb_test');
await dbTest.collection('Shirt').exist();

await zkdb.auth.signOut();

List Collections​

The zkDatabase library provides the collectionList method to retrieve a list of all collections within a specified database. This function is particularly useful for administrators and developers looking to understand the database structure, inspect available collections, or perform batch operations across multiple collections.

Definition​

The collectionList function is called on a database object, and it returns a promise that resolves to an array of collections.

await zkdb.db(databaseName: string).collectionList(): Promise<string[]>;

Parameters​

  • None

Returns​

  • Promise<string[]>: The collectionList method returns a Promise that resolves to an array of string. Each string represents the name of a collection within the specified database. This list provides insights into the database's structure and can help in planning further operations or analyses.

Example​

import { 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();


const dbTest = zkdb.db('zkdb_test');
console.log('Collections in zkdb_test:', await dbTest.collectionList());

await zkdb.auth.signOut();

Result:​

The result of the collectionList method will be an array containing the names of collections or detailed information about each collection, depending on the implementation specifics. For example:

Collections in zkdb_test: [
  'users',
  'products',
  'orders',
  // ...other collection names
]

This document provides a clear and structured explanation for retrieving collections using zkDatabase, ensuring users understand the method's functionality, parameters, and expected outcomes.