Using query parameters in Oracle APEX REST services enables you to pass additional data to your endpoints through the URL, allowing for flexible and dynamic data retrieval or processing. Query parameters are appended to the URL after a question mark (?) and consist of key-value pairs, such as ?status=active&limit=10. This approach is essential for filtering, sorting, or paginating results without changing the REST service's base URL structure.
In Oracle APEX, you can access query parameters in your RESTful services by referring to bind variables that correspond to the parameter names. For example, if the URL contains ?status=active, you can use :status in your SQL or PL/SQL code to filter data accordingly. Handling query parameters correctly allows developers to create more powerful and user-friendly APIs that respond dynamically to client requests, improving both performance and user experience.
Using query parameters in Oracle APEX REST services allows you to pass extra information through the URL to dynamically control the behavior of your service. Query parameters appear after a question mark (?) in the URL and consist of key-value pairs separated by ampersands (&), for example: ?status=active&limit=10. These parameters enable filtering, sorting, pagination, or other custom logic within your REST service.
To use query parameters in Oracle APEX, first define your RESTful service module and its REST endpoints in SQL Workshop or through RESTful Services. Within the SQL or PL/SQL code of your REST endpoint, you can reference query parameters as bind variables using the colon notation. For instance, if your URL contains ?status=active, you can access the parameter in your SQL query as :status. This allows you to write flexible queries such as:
SELECT * FROM employees WHERE status = :status
If a query parameter is not provided by the client, the bind variable will be NULL. You can handle this with NVL or CASE statements to provide default behavior. For example:
SELECT * FROM employees
WHERE status = NVL(:status, 'ACTIVE')
In addition to filtering, you can use query parameters for pagination by accepting parameters like limit and offset and applying them in your SQL using FETCH FIRST :limit ROWS ONLY or OFFSET :offset ROWS.
It is important to validate query parameters to ensure they contain expected and safe values. You can do this either within PL/SQL blocks or by adding validation logic in your REST service code to prevent SQL injection or errors.
In summary, query parameters in Oracle APEX REST services provide a powerful way to tailor responses dynamically based on client input. By referencing these parameters as bind variables in your SQL or PL/SQL, you can implement flexible filtering, sorting, and pagination while maintaining clean, reusable REST endpoints. Proper validation and default handling of parameters help ensure secure and reliable REST service operation.
Alternatively, if the RESTful service expects the employee_id as a query parameter, you can pass it like this:
Example URL:
https://your-server/ords/schema/rest/employees?id=123
In this case, modify the code to append the ID as a query parameter:
DECLARE
l_url VARCHAR2(32767);
l_response CLOB;
l_employee_id VARCHAR2(100);
BEGIN
-- Get the employee ID from the page item
l_employee_id := :P1_EMPLOYEE_ID;
-- Construct the RESTful URL with the employee ID as a query parameter
l_url := 'https://your-server/ords/schema/rest/employees?id=' || l_employee_id;
-- Make the REST call to the service
l_response := APEX_WEB_SERVICE.make_rest_request(
p_url => l_url,
p_http_method => 'GET'
);
-- Process the response
-- (Handle response as JSON or XML depending on your API)
DBMS_OUTPUT.put_line(l_response);
-- You can also populate the page items with data from the response
:P1_EMPLOYEE_DATA := l_response; -- Example: Store response in a page item
END;
Here, id is passed as a query parameter, and the API can handle this as such.
Mastering the use of query parameters in Oracle APEX REST services is vital for building robust and adaptable web applications. By efficiently capturing and using these parameters, you can tailor data responses to meet specific client needs, optimize data transfer, and maintain clean, organized REST endpoints. Implementing query parameters thoughtfully enhances your API’s flexibility and scalability, making it easier to support diverse use cases and evolving business requirements.
