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To display an image, you need to generate the URL that will display the image on a webpage. The generated URL will in turn call a proedure to retrieve the image content from the database. Both the generate URL function and the retrieve content procedure should be written by you.
A thumbnail can be generated using ORDImage APIs and once again the content should be retrieved and the URL generated for display on a webpage.
Below are some code fragments for the procedures described above. (In these examples the schema is 'security' and the table 'employees' has several columns including an 'image' and a 'thumb' column for storing the image and the thumbnail).
-- Note that function construct_URL generates a URL that is NOT secure. It can be modified by a malicious user to
-- access content he or she is not authorized to access. Please refer to the Oracle Application Express
-- documentation on how to create a URL that is secure.
CREATE OR REPLACE FUNCTION construct_URL(p_id IN NUMBER)
RETURN VARCHAR2 IS
l_str := '<img src="SECURITY.demo_get_image?' || 'p_id=' || p_id || '"/>';
--- procedure demo_get_image has code fragments and is not complete
CREATE OR REPLACE PROCEDURE demo_get_image(p_id IN NUMBER)
…select image from table
…read content into local blob variable
IF owa_util.get_cgi_env( 'REQUEST_METHOD' ) <> 'HEAD'
wpg_docload.download_file( l_blob );
CREATE OR REPLACE PROCEDURE processImage
CURSOR C1 IS SELECT t.image, t.thumb FROM security.employees t FOR UPDATE;
FETCH C1 INTO l_image, l_thumb;
EXIT WHEN C1%NOTFOUND;
l_image.processCopy('maxScale=100 100', l_thumb);
Then the procedure in APEX could be as follows:
(employee_id = :P1_ID)