Data Management

Relevant source files

The following files were used as context for generating this wiki page:

• MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py
• MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs
• MercaditoMovil/Mercadito.Domain/Entities/User/User.cs
• MercaditoMovil/MercaditoMovil.Application/Service/AuthService.cs
• MercaditoMovil/MercaditoMovil/Controllers/LoginController.cs
• MercaditoMovil/MercaditoMovil.Application/Features/UserManagement/IAuthService.cs
• MercaditoMovil/MercaditoMovil.Application/Validators/UserValidator.cs
• MercaditoMovil/Mercadito.Domain/Interfaces/Interface1.cs
• MercaditoMovil/MercaditoMovil/Program.cs
• MercaditoMovil/MercaditoMovil/Views/Form1.cs
• MercaditoMovil/MercaditoMovil/Views/Form1.Designer.cs

The data management strategy for MercaditoMovil is centered around a collection of CSV files that serve as the application's database. This approach facilitates easy bootstrapping and development without the need for a formal database server. The system includes a Python script for generating initial datasets and a data access layer in C# for reading from and writing to these files.

All data files are generated and stored within the MercaditoMovil.Infrastructure/DataFiles/ directory, organized into subdirectories for different data domains like People, Markets, and Commerce. The application interacts with this data through a repository pattern, abstracting the file-based storage from the application logic.

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:18-20, MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs

Data Generation

A Python script, create_csvs.py, is responsible for generating all the necessary CSV files with mock data. This script has no external dependencies and can be run to populate the DataFiles directory. It creates structured data for users, markets, producers, and product catalogs.

The script's main execution flow is as follows:

1. Generate markets.csv.
2. Load optional location data from locations.csv to generate more realistic user addresses.
3. Generate users.csv with a mix of fixed and randomly generated users.
4. Generate producers.csv with a mix of individual and company producers.
5. Generate product_catalog.csv from a predefined list.
6. Generate producer_products.csv, linking producers to catalog items with random pricing.

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:410-418

The following diagram illustrates the data generation process executed by the script.

Data Storage and Schema

Data is persisted in several CSV files. The relationships between the main entities are established through foreign key identifiers (e.g., MarketId, UserId).

The diagram below shows the entity relationships between the core data files.

users.csv

Stores application user information.

Column	Description
UserId	Unique identifier (e.g., USR-XXXXXXXX).
Username	User's login name.
Password	User's password (stored in plain text).
FirstName	User's first name.
FirstLastName	User's first last name.
SecondLastName	User's second last name.
NationalId	National identification number.
Email	User's email address.
Phone	User's phone number.
Address	User's exact address.
Province	Province of residence.
Canton	Canton of residence.
District	District of residence.
MarketId	Foreign key to the markets.csv file.

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:170-172, MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:14-15

markets.csv

Contains a list of farmers' markets, primarily within the Greater Metropolitan Area (GAM) of Costa Rica.

Column	Description
MarketId	Unique identifier (e.g., MKT-XXX).
MarketName	The full name of the market.
Province	Province where the market is located.
Canton	Canton where the market is located.
District	District where the market is located.

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:68-69

producers.csv

Stores information about product producers, who can be individuals or companies.

Column	Description
ProducerId	Unique identifier (e.g., PR-XXX).
ProducerCode	A business-facing code (e.g., PDCR-XXX).
NationalId	National ID (personal or corporate).
Name	Full name of the person or company.
Email	Contact email.
Phone	Contact phone number.
MarketId	Foreign key to the associated market.
UserId	Optional foreign key to the users.csv file if the producer is also a user.
IsActive	Boolean flag (true/false).

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:245-249

Data Access Layer

The application uses a repository pattern to abstract data operations. The IUserRepository interface defines the contract for user data management, and CsvUserRepository provides the concrete implementation that interacts with users.csv.

Sources: MercaditoMovil/Mercadito.Domain/Interfaces/Interface1.cs, MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs

This diagram shows the class relationships in the data access and application service layers.

User Retrieval and Authentication

User retrieval is performed by a sequential scan of the users.csv file. The Login process demonstrates the interaction between the controller, service, and repository.

The following sequence diagram details the login flow:

The GetByUsername method uses Microsoft.VisualBasic.FileIO.TextFieldParser to correctly handle comma-delimited fields that may be enclosed in quotes. It reads the file line by line, skipping the header, until it finds a matching username (case-insensitive).

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:39-42, 58-59

User Registration

New users are added by appending a new row to the users.csv file. The CsvUserRepository.Add method ensures the file and its directory exist, creates a header if the file is new, and then appends the formatted user data as a single line.

// MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:80-95
var line = string.Join(",",
    Q(user.UserId),
    Q(user.Username),
    Q(user.Password),
    Q(user.FirstName),
    Q(user.LastName1),
    Q(user.LastName2),
    Q(user.NationalId),
    Q(user.Email),
    Q(user.Phone),
    Q(user.ExactAddress),
    Q(user.Province),
    Q(user.Canton),
    Q(user.District),
    Q(user.MarketId));

writer.WriteLine(line);

Code snippet showing how a User object is serialized into a CSV row.
Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:80-95

The Q helper method is used to enclose each field in double quotes and escape any existing double quotes within the field's value, ensuring data integrity.

Sources: MercaditoMovil/MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:176-182

Domain Entities

User Entity

The MercaditoMovil.Domain.Entities.User class is the primary data model for an application user. It is an immutable class whose properties are set only at construction. The constructor provides null-safety by defaulting any null input strings to string.Empty, except for marketId which defaults to "MKT-000".

Property	Type	Description
UserId	string	Unique identifier.
Username	string	User's login name.
Password	string	User's password.
FirstName	string	User's first name.
LastName1	string	User's first last name.
LastName2	string	User's second last name.
NationalId	string	National identification number.
Email	string	User's email address.
Phone	string	User's phone number.
ExactAddress	string	User's exact address.
Province	string	Province of residence.
Canton	string	Canton of residence.
District	string	District of residence.
MarketId	string	ID of the user's preferred market.

Sources: MercaditoMovil/Mercadito.Domain/Entities/User/User.cs:8-53