# Quick Start Guide for Future AI Agents

## What This Project Is

A .NET database migration library that helps applications manage database schema changes across versions, supporting SQL Server and SQLite with flexible metadata storage.

## What Was Accomplished This Session

✅ Added multi-schema support for SQL Server  
✅ Added table/file prefixing for service isolation
✅ Implemented placeholder-based SQL script system
✅ Simplified Entity Framework configurations  
✅ Added comprehensive validation rules
✅ Updated all documentation

## Current Entry Points

```csharp
// Main configuration method
services.AddMigration(
    databaseType: DatabaseType.SQLServer,           // or SQLite
    metadataStorage: MetadataStorage.Database,      // or XmlFile
    metadataSchema: "myservice",                    // SQL Server only
    metadataPrefix: "svc_"                          // table/file prefix
);

// Start migrations
app.UseMigration();
```

## Key Files to Understand

1. **`DependencyInjectionExtensions.cs`** - Main entry point and configuration
2. **`ServiceConfiguration.cs`** - Central configuration object
3. **`TableNamingService.cs`** - Handles dynamic naming and SQL placeholder processing
4. **`Services/MigrationService.cs`** - Core migration execution logic
5. **`Scripts/` folders** - SQL scripts with `{MetadataSchema}` and `{TablePrefix}` placeholders

## How It Works

1. User calls `AddMigration()` with configuration
2. System validates configuration and registers services
3. On `UseMigration()`, system:
   - Checks if migration tables exist, creates if needed
   - Finds script folders organized by version (1.0.0, 1.0.1, etc.)
   - Runs scripts in version order, tracks progress in metadata
   - Supports both XML file and database metadata storage

## Common Tasks for Future Development

### Adding New Database Support

1. Add enum value to `DatabaseType`
2. Create scripts in `Scripts/{NewDatabase}/` folder
3. Add case to `GetSqlResources()` in `MetadataLocationService`
4. Update `MigrationRepository.MigrationTablesAreSet()` query logic

### Adding New Validation Rules

Add to `ValidateConfiguration()` in `DependencyInjectionExtensions.cs`

### Modifying SQL Scripts

Edit scripts in `Scripts/` folders using placeholders:

- `{MetadataSchema}` for schema names
- `{TablePrefix}` for table prefixes

### Testing Changes

```bash
dotnet build  # Should compile without errors
```

## Project Dependencies

- .NET 8.0
- Entity Framework Core (SQL Server + SQLite providers)
- Microsoft.Extensions.\* packages for DI and logging

## Current Limitations

- No rollback support
- No MySQL/PostgreSQL support
- No unit tests implemented
- No migration script validation

## User Preferences (Important!)

- Prefers simplicity over complexity
- Likes placeholder systems over dynamic generation
- Values dependency injection and testability
- Wants clear validation with helpful error messages
- Prefers embedded resources over external files