DatabaseMigrationHelper Documentation (VB.NET)

Overview

The DatabaseMigrationHelper class provides comprehensive functionality for managing database migrations and schema changes. It enables seamless control over database schema evolution, data transformation, validation, and backup/restore operations.

Features

• Migration system management
• Schema change tracking
• Data transformation
• Database validation
• Backup and restore
• Error handling and logging

Installation

NuGet Package Manager

            
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Install-Package DatabaseMigrationHelper
        

.NET CLI

            
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dotnet add package DatabaseMigrationHelper
        

Usage

Initialize the Helper

            
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Imports Helpers
Imports Microsoft.Extensions.Logging

' Create with optional logger
Dim loggerFactory = LoggerFactory.Create(Sub(builder) builder.AddConsole())
Dim logger = loggerFactory.CreateLogger(Of DatabaseMigrationHelper)
Dim migrationHelper = New DatabaseMigrationHelper(logger)
        

Initialize a Migration System

            
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Dim config = New SystemConfiguration With {
    .Name = "MainMigrationSystem"
    ' Add other configuration parameters
}

Dim options = New InitializationOptions With {
    ' Specify initialization options
}

Dim systemId As String = Await migrationHelper.InitializeSystem(config, options)
        

Create a Migration

            
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Dim migrationParams = New MigrationParameters With {
    .Name = "AddUserTable",
    .Description = "Creates the Users table with basic fields",
    .Changes = {
        New SchemaChanges With {
            ' Define schema changes
        }
    },
    .Transforms = {
        New DataTransforms With {
            ' Define data transformations
        }
    }
}

Dim migrationId As String = Await migrationHelper.CreateMigration(systemId, migrationParams)
        

Apply a Migration

            
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Dim applyParams = New ApplyParameters With {
    .ValidateBeforeApply = True,
    .CreateBackup = True,
    .AutoRollbackOnError = True,
    .Timeout = TimeSpan.FromMinutes(5)
}

Dim migrationResult = Await migrationHelper.ApplyMigration(systemId, migrationId, applyParams)
        

Rollback a Migration

            
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Dim rollbackParams = New RollbackParameters With {
    .ValidateAfterRollback = True,
    .RestoreBackup = True,
    .Timeout = TimeSpan.FromMinutes(5)
}

Dim rollbackResult = Await migrationHelper.RollbackMigration(systemId, migrationId, rollbackParams)
        

Transform Data

            
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Dim transformParams = New TransformParameters With {
    .SourceTable = "OldUsers",
    .TargetTable = "NewUsers",
    .Rules = {
        New TransformRule With {
            ' Define transformation rules
        }
    }
}

Dim transformResult = Await migrationHelper.TransformData(systemId, transformParams)
        

Validate Database

            
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Dim validateParams = New ValidationParameters With {
    .ValidateSchema = True,
    .ValidateData = True,
    .ValidateConstraints = True,
    .CustomRules = {
        New ValidationRule With {
            ' Define custom validation rules
        }
    }
}

Dim validationResult = Await migrationHelper.ValidateDatabase(systemId, validateParams)
        

Create Backup

            
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Dim backupParams = New BackupParameters With {
    .BackupName = "PreMigrationBackup",
    .Type = BackupType.Full,
    .BackupPath = "C:\Backups",
    .Compression = CompressionLevel.Optimal
}

Dim backupResult = Await migrationHelper.CreateBackup(systemId, backupParams)
        

Restore Backup

            
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Dim restoreParams = New RestoreParameters With {
    .ValidateAfterRestore = True,
    .KeepExistingData = False,
    .Timeout = TimeSpan.FromMinutes(10)
}

Dim restoreResult = Await migrationHelper.RestoreBackup(systemId, backupId, restoreParams)
        

Error Handling

The helper uses the DatabaseMigrationException class for error handling:

            
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Try
    Dim result = Await migrationHelper.ApplyMigration(systemId, migrationId, applyParams)
Catch ex As DatabaseMigrationException
    logger.LogError($"Migration failed: {ex.Message}")
    ' Handle the error
End Try
        

Best Practices

1. Migration Planning

   • Plan migrations carefully before execution
   • Test migrations in development environment
   • Always create backups before migrations

2. Data Safety

   • Validate data before and after migrations
   • Use appropriate backup strategies
   • Implement proper error handling

3. Performance Optimization

   • Schedule migrations during low-traffic periods
   • Use appropriate timeout values
   • Monitor system resources during migration

4. Safety Considerations

   • Validate all migration parameters
   • Test rollback procedures
   • Maintain proper backup strategy

Advanced Features

Backup Types

            
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Public Enum BackupType
    Full
    Differential
    Incremental
End Enum
        

Compression Levels

            
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Public Enum CompressionLevel
    None
    Fast
    Optimal
End Enum
        

API Reference

Classes

• DatabaseMigrationHelper: Main helper class
• MigrationSystem: Migration system container
• DatabaseMigrationException: Custom exception class

Key Methods

• InitializeSystem: Initialize a new migration system
• CreateMigration: Create a new migration
• ApplyMigration: Apply a migration
• RollbackMigration: Rollback a migration
• TransformData: Transform data
• ValidateDatabase: Validate database
• CreateBackup: Create database backup
• RestoreBackup: Restore database backup

Version History

• 1.0.0: Initial release
• 1.1.0: Added data transformation
• 1.2.0: Improved backup/restore
• 1.3.0: Enhanced validation

License

MIT License - See LICENSE file for details