class SemanticModelsError(Exception):
    """Base exception for Semantic Models application."""

    pass


class NotFoundError(SemanticModelsError):
    """Raised when a requested resource is not found."""

    pass


class ValidationError(SemanticModelsError):
    """Raised when validation fails."""

    pass


class ConfigurationError(SemanticModelsError):
    """Raised when there's a configuration issue."""

    pass


class ExecutionError(SemanticModelsError):
    """Raised when SQL execution fails."""

    pass
