Overview

Developed by	Guardrails AI
Date of development	Feb 15, 2024
Validator type	Format
Blog	-
License	Apache 2
Input/Output	Output

Description

This validator checks if a string follows valid SQL code. In order to do this, it expects either a conn string or a schema file. It checks the validity of generated SQL by performing the following steps:

1. If given a connection string, it connects to the DB instance.
2. Alternatively, if given a schema, it creates a local instance of the database based on the schema and connects to the local DB.
3. If neither a connection string nor schema is provided, then SQL validation is performed using sqlvalidator package.
4. In order to validate any generated LLM string representing a SQL statement, that statement is executed against the connected DB. If the statement runs without raising an exception, then the validator passes.

Installation

guardrails hub install hub://guardrails/valid_sql

Usage Examples

Validating string output via Python

In this example, we validate a generated SQL code by providing it with a schema file.

# Import Guard and Validator
from guardrails import Guard
from guardrails.hub import ValidSQL

# Setup Guard
guard = Guard().use(ValidSQL, on_fail="exception")
response = guard.validate("SELECT * FROM EMPLOYEES;")  # Validator passes

try:
    response = guard.validate("SELEKT ID FROM USERS;")  # Validator fails
except Exception as e:
    print(e)

Output:

Validation failed for field with errors:

API Reference

__init__(self, conn=None, schema=None, on_fail="noop")

Initializes a new instance of the Validator class.

Parameters:

• conn (str): The connection string to connect to a sql schema. E.g. sqlite://
• schema (str): The .sql file representing the DB schema.
• on_fail (str, Callable): The policy to enact when a validator fails. If str, must be one of reask, fix, filter, refrain, noop, exception or fix_reask. Otherwise, must be a function that is called when the validator fails.

__call__(self, value, metadata={}) → ValidationResult

Validates the given value using the rules defined in this validator, relying on the metadata provided to customize the validation process. This method is automatically invoked by guard.parse(...), ensuring the validation logic is applied to the input data.

Note:

1. This method should not be called directly by the user. Instead, invoke guard.parse(...) where this method will be called internally for each associated Validator.
2. When invoking guard.parse(...), ensure to pass the appropriate metadata dictionary that includes keys and values required by this validator. If guard is associated with multiple validators, combine all necessary metadata into a single dictionary.

Parameters:

• value (Any): The input value to validate.
• metadata (dict): A dictionary containing metadata required for validation. For this validator, no additional metadata keys are required.