Solving the Enigma: Duck DB with Angular Unable to Load and Query Parquet File

Are you tired of scratching your head, trying to figure out why your Angular application won’t load and query your Parquet file using Duck DB? Well, buckle up, friend, because we’re about to dive into the solution!

The Problem: A Quick Recap

For those who might be new to this issue, let’s quickly recap what’s going on. You’ve got an Angular application, and you’re trying to use Duck DB to load and query a Parquet file. Sounds simple, right? But, for some reason, it just won’t work. You’ve tried everything: from tweaking the configuration to reinstalling the dependencies, but nothing seems to fix the issue.

What’s Going On?

The problem lies in the way Duck DB interacts with the Parquet file and Angular. By default, Duck DB uses the `fs` module to read and write files, which doesn’t work well with Angular’s environment. Additionally, Parquet files require specific dependencies to be installed and configured correctly.

The Solution: Step-by-Step Guide

Don’t worry, we’ve got you covered! Follow these steps to get Duck DB working with your Parquet file in Angular:

1. Install Required Dependencies

   First things first, make sure you have the necessary dependencies installed. Run the following commands in your terminal:

   npm install --save @duckdb/duckdb
   npm install --save @duckdb/fs
   npm install --save parquetjs
   npm install --save @angular/common

2. Configure Duck DB

   Create a new file called `duckdb.config.js` in the root of your Angular project with the following content:

   const duckdb = require('@duckdb/duckdb');
   const fs = require('@duckdb/fs');
   
   duckdb.configure({
     fs: fs,
     loadExtensions: true,
     verbose: true,
   });
   
   module.exports = duckdb;

3. Load Parquet File

   Next, create a new service in your Angular application to load the Parquet file using Duck DB. Create a new file called `parquet.service.ts` with the following content:

   import { Injectable } from '@angular/core';
   import * as duckdb from './duckdb.config';
   
   @Injectable({
     providedIn: 'root'
   })
   export class ParquetService {
   
     async loadParquetFile(path: string) {
       const db = new duckdb.Database();
       const connection = db.connect();
       const query = `REGISTER FILE '${path}' AS parquet_file;`;
       await connection.query(query);
       return connection;
     }
   
   }

4. Query Parquet File

   Now, create a new component to query the Parquet file using the `ParquetService`. Create a new file called `parquet.component.ts` with the following content:

   import { Component, OnInit } from '@angular/core';
   import { ParquetService } from './parquet.service';
   
   @Component({
     selector: 'app-parquet',
     template: '
   Parquet Data: {{ data | json }}
   '
   })
   export class ParquetComponent implements OnInit {
   
     data: any;
   
     constructor(private parquetService: ParquetService) { }
   
     async ngOnInit() {
       const connection = await this.parquetService.loadParquetFile('path/to/your/parquet/file.parquet');
       const query = 'SELECT * FROM parquet_file;';
       const result = await connection.query(query);
       this.data = result.data;
     }
   
   }

Troubleshooting Tips

If you’re still running into issues, here are some troubleshooting tips to help you out:

• Make sure you’ve installed all the required dependencies and configured Duck DB correctly.

• Check the file path and permissions to ensure Duck DB can read and write to the Parquet file.

• Verify that the Parquet file is in the correct format and not corrupted.

• Use the `verbose` mode in Duck DB to get more detailed error messages.

Conclusion

And that’s it! With these steps and troubleshooting tips, you should be able to load and query your Parquet file using Duck DB in your Angular application. Remember to stay calm, and don’t hesitate to reach out if you encounter any issues.

Dependency	Version
@duckdb/duckdb	^0.3.1
@duckdb/fs	^0.3.1
parquetjs	^3.0.0
@angular/common	^12.2.16

Note: The versions listed above are subject to change, and you should always check for the latest versions.

Frequently Asked Question

Having trouble with Duck DB and Angular when loading and querying parquet files? Don’t worry, we’ve got you covered! Below are some frequently asked questions and answers to help you overcome these challenges.