Validation Engine

Validation Engine

The Generic SQL API Framework includes a built-in validation engine that verifies every request before executing a SQL query. This helps prevent invalid requests, improve reliability, and reduce runtime errors.

---

Validation Flow

Every request follows this validation process:

Client Request
      │
      ▼
JSON Validation
      │
      ▼
Query Validation
      │
      ▼
Parameter Validation
      │
      ▼
Security Checks
      │
      ▼
Execute SQL
      │
      ▼
Return Response

---

Request Validation

The framework first validates the incoming JSON request.

Example:

{
    "query": "customers"
}

Checks performed:

• Request is valid JSON
• Required properties exist
• Property names are valid
• Request is not empty

---

Query Validation

The framework verifies that the requested SQL file exists.

Example:

{
    "query": "customers"
}

The framework checks:

queries/customers.sql

If the file does not exist:

{
    "success": false,
    "message": "Query file not found."
}

---

Parameter Validation

Parameterized queries require matching input values.

SQL:

SELECT *
FROM CustomerTable
WHERE CustomerID = :CustomerID;

JSON:

{
    "query": "customer_by_id",
    "parameters": {
        "CustomerID": 101
    }
}

If a required parameter is missing:

{
    "success": false,
    "message": "Missing required parameter: CustomerID"
}

---

Data Type Validation

The framework validates parameter types before execution.

Example:

{
    "parameters": {
        "CustomerID": "ABC"
    }
}

If the query expects an integer, validation fails.

---

Pagination Validation

The framework validates pagination values.

Example:

{
    "pagination": {
        "page": 1,
        "pageSize": 50
    }
}

Validation rules:

• Page must be greater than 0
• Page size must be greater than 0
• Maximum page size depends on framework configuration

---

Sorting Validation

Example:

{
    "sorting": {
        "column": "CustomerName",
        "direction": "ASC"
    }
}

Checks:

• Column exists
• Direction is either ASC or DESC

---

Filter Validation

Example:

{
    "filters": {
        "City": "Bangalore"
    }
}

Validation includes:

• Allowed filter fields
• Supported operators
• Valid values

---

Security Validation

Before executing SQL, the framework performs security checks such as:

• Preventing SQL injection through parameterized queries
• Rejecting invalid or malformed requests
• Restricting execution to registered SQL files

---

Validation Response

Successful validation:

{
    "success": true
}

Validation error:

{
    "success": false,
    "message": "Validation failed."
}

---

Best Practices

• Always use parameterized queries.
• Validate user input before sending requests.
• Use meaningful parameter names.
• Keep SQL queries simple and maintainable.
• Test validation scenarios during development.

---

Next Steps

Now that you understand request validation, continue with:

• Query Examples
• Response Format
• Error Handling
• Framework Architecture