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SupermarketWEB uses SQL Server LocalDB with Entity Framework Core 8.0 for data persistence. This guide covers database configuration, context setup, and initialization.

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Prerequisites

1

SQL Server LocalDB

Install SQL Server LocalDB (included with Visual Studio) or SQL Server Express
2

Entity Framework Core Tools

Install EF Core tools globally:
dotnet tool install --global dotnet-ef

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Connection String Configuration

The database connection is configured in appsettings.json:
appsettings.json
{
  "ConnectionStrings": {
    "SupermarketDB": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=SupermarketEF;Integrated Security=True;Connect Timeout=30;Encrypt=False;Trust Server Certificate=False;Application Intent=ReadWrite;Multi Subnet Failover=False"
  }
}
The connection string uses SQL Server LocalDB with integrated security, which authenticates using your Windows credentials. No separate username or password is required.

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Connection String Parameters

ParameterValuePurpose
Data Source(localdb)\\MSSQLLocalDBLocalDB instance name
Initial CatalogSupermarketEFDatabase name
Integrated SecurityTrueUse Windows authentication
EncryptFalseDisable connection encryption for local development
For production environments, change the connection string to use a full SQL Server instance with proper encryption and authentication.

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Entity Framework Core Configuration

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DbContext Registration

The SupermarketContext is registered in Program.cs:
Program.cs
using Microsoft.EntityFrameworkCore;
using SupermarketWEB.Data;

var builder = WebApplication.CreateBuilder(args);

// Register DbContext with SQL Server provider
builder.Services.AddDbContext<SupermarketContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("SupermarketDB"))
);
This configuration:
  • Registers SupermarketContext in the dependency injection container
  • Configures the SQL Server provider
  • Reads the connection string from appsettings.json

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DbContext Implementation

The SupermarketContext class in Data/SupermarketContext.cs defines all database tables:
Data/SupermarketContext.cs
using Microsoft.EntityFrameworkCore;
using SupermarketWEB.Models;

namespace SupermarketWEB.Data
{
    public class SupermarketContext : DbContext
    {
        public SupermarketContext(DbContextOptions options) : base(options)
        {
        }

        public DbSet<Product> Products { get; set; }
        public DbSet<Category> Categories { get; set; }
        public DbSet<Customer> Customers { get; set; }
        public DbSet<PayMode> PayModes { get; set; }
        public DbSet<User> Users { get; set; }
    }
}
Each DbSet<T> property represents a table in the database:
  • Products - Product inventory items
  • Categories - Product categories
  • Customers - Customer information
  • PayModes - Payment methods
  • Users - Application users for authentication

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Database Initialization

1

Create Initial Migration

Generate the first migration to create database schema:
dotnet ef migrations add InitialCreate
This creates a migration file in the Migrations folder with the database schema definition.
2

Apply Migration to Database

Create the database and apply the migration:
dotnet ef database update
This command:
  • Creates the SupermarketEF database if it doesn’t exist
  • Applies all pending migrations
  • Creates tables for all DbSet properties
3

Verify Database Creation

Connect to LocalDB using SQL Server Object Explorer in Visual Studio or SQL Server Management Studio to verify the database and tables were created successfully.

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Working with Migrations

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Create a New Migration

After modifying model classes, create a new migration: 
dotnet ef migrations add <MigrationName>
Use descriptive migration names like AddProductStockColumn or CreateCustomersTable to make the migration history clear.

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Apply Migrations

Update the database with pending migrations: 
dotnet ef database update

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Rollback Migration

Revert to a specific migration: 
dotnet ef database update <PreviousMigrationName>

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Remove Last Migration

Remove the most recent unapplied migration: 
dotnet ef migrations remove
Only remove migrations that haven’t been applied to production databases. Removing applied migrations can cause data loss.

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Database Schema

The SupermarketWEB database includes the following entities:
  • Id (int, primary key)
  • Name (string)
  • Price (decimal(6,2))
  • Stock (int)
  • CategoryId (int, foreign key)
Relationships: Many-to-One with Category
  • Id (int, primary key)
  • Name (string)
  • Description (string, nullable)
Relationships: One-to-Many with Products
  • Id (int, primary key)
  • Customer-specific fields (see Models/Customer.cs)
  • Id (int, primary key)
  • Payment mode fields (see Models/PayMode.cs)
  • Id (int, primary key)
  • Authentication fields (see Models/User.cs)

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Troubleshooting

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LocalDB Instance Not Found

If you encounter connection errors, verify LocalDB is installed: 
sqllocaldb info
Create a new LocalDB instance if needed: 
sqllocaldb create MSSQLLocalDB
sqllocaldb start MSSQLLocalDB

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Migration Errors

If migrations fail, check:
  • Ensure the database is not in use by other applications
  • Verify connection string credentials
  • Check migration files for conflicts
  • Review the error message for specific model or constraint issues

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Connection Timeout

Increase the connection timeout in appsettings.json if needed: 
"SupermarketDB": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=SupermarketEF;Integrated Security=True;Connect Timeout=60;..."

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Next Steps

  • Learn about the Project Structure to understand how the application is organized
  • Explore Razor Pages to see how data is accessed and displayed

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