> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/introduction-to-etl-pipeline/exercise-4-etl-pipeline-csv-source-and-ftp-connector-using-sections.md).

# Exercise 4: ETL pipeline, CSV Source & FTP Connector using Sections

In this exercise, store data in an Entity with a formatted date.

## Requirements

* For this exercise, use a CSV file with the following fields containing customer information.

{% hint style="info" %}
This is just test data, not real, and has been auto-generated by <http://www.convertcsv.com/generate-test-data.htm>. \
In this exercise, the joining date information is in the wrong format, and actions will be defined to correct it before storing it in the entity.&#x20;
{% endhint %}

* Store data through the ETL pipeline.&#x20;
* Use an FTP tool to establish a connection with the Langstack application. In this exercise, the tool in use is Filezilla.&#x20;
* File must be residing on the FTP server before the execution of the ETL pipeline starts.&#x20;
* Create entity “UserName\_Acc\_customers”.&#x20;
* Store the data from the CSV file in the entity “UserName\_Acc\_customers” after the following:&#x20;
  * Format the date to align with the format of the entity&#x20;
  * Create additional fields for
    * DayMonthJoinDate
    * Customer\_Value
    * Rating

## Solution

The CSV file stores customer information, which needs to be updated in the Customer entity. However, two issues need to be sorted beforehand:

1. The joining date for the customer in this file is in the format (M/DD/YYYY), whereas the format of the Join\_Date in the entity is (MM/DD/YYYY). The joining date values must be reformatted before storing in the entity.&#x20;
2. Three fields DateMonthJoinDate, Customer\_Value, and Rating are not present in the CSV file. These fields must be created in the ETL pipeline and assigned relevant values. \
   \
   The solution is based on the following steps:

* Step 1: Create the ETL pipeline adding the three extra fields for:
  * DateMonthJoinDate
  * Customer\_Value
  * Rating. \
    Map the Reader and Writer fields.&#x20;
* Step 2: When the ETL pipeline is created, define actions to convert the format of the Join\_Date received in the Reader to align with the format of the Join\_Date field in the target entity. Also, define Actions to assign values to Customer\_Value and Rating fields before storing in the entity.