🌍 CountrySeeder

A high-performance EF Core seeding tool that imports countries, states, and cities into a PostgreSQL database from a large JSON file.
It uses EFCore.BulkExtensions for blazing-fast data insert and supports command-line or environment-based configuration.

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📦 Features

• ⚡ Bulk insert with EFCore.BulkExtensions
• 🌐 Loads hierarchical country-state-city data from countries_states_cities.json
• 🧩 Supports full JSON structure: coordinates, translations, timezones, etc.
• 🧼 Automatic truncate of existing data (with CASCADE and identity reset)
• 🧪 Safe seeding: detects existing records and skips unless --force is used
• 💻 CLI/ENV-based config (--force, --truncate, connection string)

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📁 Folder Structure

CountrySeeder/
├── Program.cs						   → Entry point with seeding logic
├── AppDbContext.cs					   → EF Core DbContext
├── Entities/						   → Country, State, City entities
├── Models/							   → CountryModel, StateModel, CityModel (for deserialization)
├── countries\_states\_cities.json     → JSON data source (not included in repo)

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🚀 Usage

1. 🔧 Set Up

Install dependencies:

dotnet restore

Add the required NuGet package:

dotnet add package EFCore.BulkExtensions

Make sure your PostgreSQL database has the following tables:

• Countries
• States
• Cities

Tip: Use EF Core migrations if needed.

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2. 📦 Run Seeder

With command-line argument:

dotnet run -- "Host=localhost;Database=GeoDb;Username=postgres;Password=1234"

With environment variable:

set Geo_Connection_String=Host=localhost;Database=GeoDb;Username=postgres;Password=1234
dotnet run

Run executable in powershell:

CountrySeeder.exe "Username=;Password=;Server=;Port=5432;Database=yourdb" --force

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3. 🧪 Optional Flags

Flag / Env	Description
--force	Forces seeding even if tables already contain data
FORCE_SEED=true	Same as --force, for CI or container use

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🧬 JSON Format

This tool expects a file named countries_states_cities.json at the root. File exists in folder but if not exists;

You can download it from the original source:

📥 https://github.com/dr5hn/countries-states-cities-database/blob/master/json/countries%2Bstates%2Bcities.json

Rename to: countries_states_cities.json

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✅ Example Output

Checking table existence...
Cleaning tables...
Seeding starting...
Reading json data file...
Seeding...
✔ Completed!
All seed operations has been completed!

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🛠 Dependencies

• .NET 8+
• PostgreSQL 12+
• EF Core Bulk Extensions

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📄 License

MIT License © 2025 – use freely, attribution appreciated!