DbExceptionClassifier

Classify ADO.NET database exceptions by error type. Works with any ADO.NET provider without requiring Entity Framework Core.

Supports PostgreSQL, SQL Server, SQLite, Oracle, MySQL (MySql.Data and MySqlConnector).

What does DbExceptionClassifier do?

When working with ADO.NET, database exceptions are provider-specific. To determine whether an error was caused by a unique constraint violation, a foreign key violation, or a null constraint, you need to inspect the provider-specific exception type and error codes.

DbExceptionClassifier provides a unified IDbExceptionClassifier interface that classifies DbException instances into common error types:

• Unique constraint violation
• Reference (foreign key) constraint violation
• Cannot insert null
• Max length exceeded
• Numeric overflow
• Deadlock

Getting started

Install the package for your database:

dotnet add package DbExceptionClassifier.PostgreSQL

dotnet add package DbExceptionClassifier.SqlServer

dotnet add package DbExceptionClassifier.Sqlite

dotnet add package DbExceptionClassifier.Oracle

dotnet add package DbExceptionClassifier.MySQL

dotnet add package DbExceptionClassifier.MySQL.Pomelo

Usage

Create an instance of the classifier for your database and use it to classify exceptions:

var classifier = new PostgreSQLExceptionClassifier();

try
{
    // Execute your ADO.NET command
    await command.ExecuteNonQueryAsync();
}
catch (DbException ex) when (classifier.IsUniqueConstraintError(ex))
{
    // Handle unique constraint violation
}
catch (DbException ex) when (classifier.IsReferenceConstraintError(ex))
{
    // Handle foreign key violation
}

IDbExceptionClassifier interface

public interface IDbExceptionClassifier
{
    bool IsUniqueConstraintError(DbException exception);
    bool IsReferenceConstraintError(DbException exception);
    bool IsCannotInsertNullError(DbException exception);
    bool IsMaxLengthExceededError(DbException exception);
    bool IsNumericOverflowError(DbException exception);
    bool IsDeadlockError(DbException exception);
}

CompositeExceptionClassifier

If your application connects to multiple database types, use CompositeExceptionClassifier to combine multiple classifiers into one. It delegates to each classifier and returns true if any of them matches:

var classifier = new CompositeExceptionClassifier(
    new PostgreSQLExceptionClassifier(),
    new SqlServerExceptionClassifier()
);

try
{
    await command.ExecuteNonQueryAsync();
}
catch (DbException ex) when (classifier.IsUniqueConstraintError(ex))
{
    // Works regardless of which database threw the exception
}

Entity Framework Core

If you are using Entity Framework Core, use the EntityFrameworkCore.Exceptions packages instead. They build on top of DbExceptionClassifier and provide typed exceptions that inherit from DbUpdateException.