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Learn how to dynamically pass parameter values into your custom JPA queries in Spring Boot for effective database management.
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How to Pass Parameter Values into Queries in Spring Boot

In the world of web development, building efficient and dynamic applications is a top priority. When working with databases in a Spring Boot application, you might encounter situations where you need to pass parameters dynamically into your custom queries. This is common when using JPA (Java Persistence API) to interact with your database. In this post, we'll address a common issue developers face when trying to pass parameter values into queries in Spring Boot, and provide a clear solution.

The Problem: Passing Parameters in JPA Queries

Suppose you have a JPA repository set up to query a customer table in your database. The goal is to search for customers by their first name based on a keyword input. Here's a typical way to define the query:

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At first glance, this query seems correct. However, the parameter you are trying to include within the like clause is not functioning as expected because of how it's written. The expression '%:keyword%' is treated as a literal string, which means the parameter will not be replaced with the actual value you pass.

The Solution: Correctly Passing Parameters

To resolve this issue, you need to use the CONCAT function within your query. By doing so, you can dynamically construct the string that includes your parameter. Here's how you can modify your query:

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Explanation of the Changes

CONCAT: This function concatenates the parameter value with the wildcard characters %, allowing for a more dynamic search. It allows the query to correctly identify records that contain the keyword you are searching for, regardless of its position in the first name field.

How to Use Your Enhanced Query

With the updated query in place, you can now call findByKeyword and pass any keyword string you want. Here's a quick example of how you might call this method from a service layer:

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This would return all customers in the customer_tbl whose first names contain the substring "John."

Conclusion

Dynamically passing parameter values into your JPA queries in Spring Boot is essential for creating responsive applications. By replacing a literal string with a CONCAT function, you can ensure that parameter values are inserted correctly, allowing your queries to return the expected results. This simple tweak can save you time and frustration as you continue developing your Spring Boot applications.

Make sure to apply this technique whenever you need to pass dynamic parameters in your queries, and avoid the common pitfalls associated with string literals in SQL.

Feel free to reach out with any questions or further clarifications needed on this topic!