Difference Between Native Query and JPQL Query

Native Query and JPQL query are two different approaches that allow us to write manual queries for interacting with the database in JPA, but the difference between Native Query and JPQL query differ in syntax, flexibility, portability, and use cases to each other. We need to understand their differences is crucial for selecting the appropriate query type for our Spring Boot application.

This topic will explain the difference between Native Query and JPQL, their strengths, and provide practical examples to help us decide which to use.

What is a Native Query in JPA?

A Native Query allows us to write raw SQL queries directly in JPA using @Query and @NamedNativeQuery annotations. It operates directly on database tables and columns, providing complete control over SQL syntax.

Key Features of Native Query

• Uses raw SQL, making it database-specific.
• Provides access to advanced database features (e.g., LIMIT, ROWNUM).
• Requires explicit result mapping for entities or DTOs.
• Validated at runtime when executed.

Syntax Example: Native Query

@Query(value = "SELECT * FROM orders WHERE status = :status", nativeQuery = true)
List<Order> findByStatusNative(String status);

What is JPQL query in JPA?

A JPQL query is a database-independent query that works on JPA entity classes and their properties instead of table names and column names. Abstracting away the underlying database schema helps simplify querying. We can write a JPQL query in JPA using the @Query and @NamedQuery annotations.

Key Features of JPQL

• Works with entity attributes instead of database columns.
• Database-independent and portable.
• Automatically maps results to entities.
• Validated at application startup.

Syntax Example: JPQL Query

@Query("SELECT o FROM Order o WHERE o.status = :status")
List<Order> findByStatus(String status);

Key Difference Between Native Query and JPQL Query

Feature	Native Query	JPQL Query
Syntax	It uses raw SQL and operates on database tables and columns.	It uses JPQL and operates on JPA entities and attributes.
Portability	Database-specific, not portable.	Database-independent, portable across systems.
Validation	Validated during runtime when the query is executed.	Validated at application startup.
Result Mapping	Requires explicit mapping to entities or DTOs.	Automatically maps results to entities.
Flexibility	It fully supports advanced SQL features and functions.	Limited by JPQL capabilities.
Use Case	Ideal for complex queries and database-specific features.	Best for simple, standard queries.
Performance	Executes directly in the database for optimised performance.	May involve JPQL-to-SQL translation overhead.

When to Use Native Query?

• Complex SQL Requirements: Use when queries involve advanced SQL constructs like joins, subqueries, or aggregations.
• Database-Specific Optimizations: Leverage database-specific features like LIMIT or functions.
• Legacy Systems: Ideal for integrating with pre-written SQL queries or stored procedures.

Example Use Case for Native Query

Fetching the top 5 most expensive orders:

@Query(value = "SELECT * FROM orders ORDER BY price DESC LIMIT 5", nativeQuery = true)
List<Order> findTop5ExpensiveOrders();

When to Use JPQL?

• Portability: Use JPQL when you need database-agnostic queries.
• Entity-Centric Queries: For standard CRUD operations and queries involving entity attributes.
• Validation at Startup: When you want queries validated during application initialization.

Example Use Case for JPQL

Fetching all orders with a specific status:

@Query("SELECT o FROM Orders o WHERE o.status = :status")
List<Order> findByStatus( String status);

Practical Comparison

Scenario	Native Query	JPQL Query
Fetching orders by status	Direct SQL query on the status column.	Uses entity attribute status.
Fetching top N records	Supports LIMIT or database-specific syntax.	Not supported in JPQL.
Using database-specific functions	Fully supported (e.g., ROUND, NOW).	Not supported (limited to JPQL functions).
Multi-database compatibility	May require query modification.	Works seamlessly across databases.

Advantages of Native Query

• Flexibility: Provides full control over SQL syntax.
• Advanced SQL Support: Ideal for complex queries and database-specific features.
• Performance Optimization: Executes directly in the database.

Advantages of JPQL Query

• Portability: Works across multiple database systems without modification.
• Ease of Use: Abstracts away database schema and uses entity attributes.
• Validation: Detects errors at application startup.

Best Practices

For Native Query:

• Use parameters (:param) to prevent SQL injection.
• Optimize queries for the target database.
• Map results explicitly for complex queries or DTOs.

For JPQL Query:

• Prefer JPQL for standard, entity-based queries to maintain portability.
• Avoid overly complex JPQL logic for better readability.
• Test JPQL queries across multiple databases to ensure compatibility.

Conclusion

Both Native Query and JPQL are powerful tools in JPA for querying data:

• Use Native Query for advanced, performance-critical, or database-specific queries.
• Use JPQL Query for standard, portable, and entity-centric operations.