Bypass the JSON object using PL / SQL, and output all data in key value format in Oracle - sql

Question

I have JSON, I want to bypass it and display all the data that is in it. But the problem is that I can't know what data will be there. I made the code, but it only looks for top-level objects. And the rest are not. I will be grateful for your help.
DECLARE
l_object json_object_t;
l_key_list json_key_list;
v_clob CLOB;
tv apex_json.t_values;
BEGIN
-- JSON_OBJECT can figure out what keys it has...
v_clob := '{"devices":{"id":"d652f632-0835-871b-a140-58701f019000","scale_id":"88348A32BD3D149FE055000000000001"},"data":{"external_id":"40023"},"data_weight":{"weight":"20322","prevWeight":"1000","prevTransaction":"1607680754361","transaction":"1607680754361","on":"false","transactionDataCount":"1","stable":"false","duration":"12","transactionMaxWeight":"2000","perimetr":"true","driverInCar":"false"}}';
apex_json.parse(tv,v_clob);
l_object := json_object_t.parse (v_clob);
l_key_list := l_object.get_keys;
FOR counter IN 1 .. l_key_list.COUNT
LOOP
DBMS_OUTPUT.put_line (
l_key_list (counter)
|| ' : '
|| apex_json.get_varchar2(p_path => l_key_list (counter), p_values => tv));
END LOOP;
END;
If you take into account only the top level objects, then this code works
DECLARE
l_object json_object_t;
l_key_list json_key_list;
v_clob CLOB;
tv apex_json.t_values;
BEGIN
-- JSON_OBJECT can figure out what keys it has...
v_clob := '{"devices":"3423","data":"okwwwe"}';
apex_json.parse(tv,v_clob);
l_object := json_object_t.parse (v_clob);
l_key_list := l_object.get_keys;
FOR counter IN 1 .. l_key_list.COUNT
LOOP
DBMS_OUTPUT.put_line (
l_key_list (counter)
|| ' : '
|| apex_json.get_varchar2(p_path => l_key_list (counter), p_values => tv));
END LOOP;
END;
RESULT :
devices : 3423
data : okwwwe
And how to deduce the data from the first example, I can not understand. These data must correspond to the hierarchy.

Answer 1

If you have access to the native JSON types (JSON_ELEMENT_T, JSON_ARRAY_T, etc.) you should always use them over using the APEX_JSON package ans they will have much better performance. A package similar to the one below can be used to output the full hierarchy of a JSON object or array. Feel free to tweak the package to change the format of the output.
Package Specification
CREATE OR REPLACE PACKAGE output_json
AS
c_padding_char CONSTANT VARCHAR2 (1) := '-';
c_padding_amount CONSTANT PLS_INTEGER := 1;
PROCEDURE output_scalar (p_element json_element_t,
p_padding PLS_INTEGER,
p_json_key VARCHAR2 DEFAULT NULL);
PROCEDURE output_object (p_object json_object_t, p_padding PLS_INTEGER);
PROCEDURE output_array (p_array json_array_t, p_padding PLS_INTEGER);
PROCEDURE output_element (p_element json_element_t,
p_padding PLS_INTEGER,
p_json_key VARCHAR2 DEFAULT NULL);
END;
/
Package Body
CREATE OR REPLACE PACKAGE BODY output_json
AS
PROCEDURE output_scalar (p_element json_element_t,
p_padding PLS_INTEGER,
p_json_key VARCHAR2 DEFAULT NULL)
IS
BEGIN
DBMS_OUTPUT.put_line (
LPAD (c_padding_char, p_padding, c_padding_char)
|| CASE WHEN p_json_key IS NOT NULL THEN p_json_key || ' : ' END
|| CASE
WHEN p_element.is_boolean
THEN
CASE WHEN p_element.to_boolean THEN 'TRUE' ELSE 'FALSE' END || ' (boolean)'
WHEN p_element.is_date
THEN
TO_CHAR (p_element.TO_DATE, 'YYYY-MM-DD') || ' (date)'
WHEN p_element.is_number
THEN
p_element.TO_NUMBER || ' (number)'
WHEN p_element.is_string
THEN
p_element.TO_STRING || ' (string)'
END);
END;
PROCEDURE output_object (p_object json_object_t, p_padding PLS_INTEGER)
IS
l_keys json_key_list;
l_element json_element_t;
BEGIN
l_keys := p_object.get_keys;
FOR i IN 1 .. l_keys.COUNT
LOOP
l_element := p_object.get (l_keys (i));
output_element (l_element, p_padding, l_keys (i));
END LOOP;
END;
PROCEDURE output_array (p_array json_array_t, p_padding PLS_INTEGER)
IS
BEGIN
FOR i IN 0 .. p_array.get_size - 1
LOOP
output_element (p_array.get (i), p_padding);
END LOOP;
END;
PROCEDURE output_element (p_element json_element_t,
p_padding PLS_INTEGER,
p_json_key VARCHAR2 DEFAULT NULL)
IS
BEGIN
DBMS_OUTPUT.put_line (
CASE
WHEN p_json_key IS NOT NULL AND NOT p_element.is_scalar THEN p_json_key || ' : '
END);
IF p_element.is_scalar
THEN
output_scalar (p_element, p_padding, p_json_key);
ELSIF p_element.is_object
THEN
output_object (TREAT (p_element AS json_object_t), p_padding + c_padding_amount);
ELSIF p_element.is_array
THEN
output_array (TREAT (p_element AS json_array_t), p_padding + c_padding_amount);
END IF;
END;
END;
/
Example Call
DECLARE
l_clob CLOB;
BEGIN
l_clob :=
'{"arr":[1,2,3],"devices":{"id":"d652f632-0835-871b-a140-58701f019000","scale_id":"88348A32BD3D149FE055000000000001"},"data":{"external_id":"40023"},"data_weight":{"weight":"20322","prevWeight":"1000","prevTransaction":"1607680754361","transaction":"1607680754361","on":"false","transactionDataCount":"1","stable":"false","duration":"12","transactionMaxWeight":"2000","perimetr":"true","driverInCar":"false"}}';
output_json.output_element (json_element_t.parse (l_clob), 0);
END;
/
Example Output
arr :
--1 (number)
--2 (number)
--3 (number)
devices :
--id : "d652f632-0835-871b-a140-58701f019000" (string)
--scale_id : "88348A32BD3D149FE055000000000001" (string)
data :
--external_id : "40023" (string)
data_weight :
--weight : "20322" (string)
--prevWeight : "1000" (string)
--prevTransaction : "1607680754361" (string)
--transaction : "1607680754361" (string)
--on : "false" (string)
--transactionDataCount : "1" (string)
--stable : "false" (string)
--duration : "12" (string)
--transactionMaxWeight : "2000" (string)
--perimetr : "true" (string)
--driverInCar : "false" (string)

Answer 2

I also made my own version, but it is limited to 2 levels of objects, and does not take into account arrays.
DECLARE
l_object json_object_t;
l_key_obj json_key_list;
v_clob CLOB;
tv apex_json.t_values;
obj_in_obj JSON_OBJECT_T;
l_key_list json_key_list;
BEGIN
v_clob := '{
"devices":{
"id":"d652f632-0835-871b-a140-58701f019000",
"scale_id":"88348A32BD3D149FE055000000000001"
},
"data":{
"external_id":"40023"
},
"data_weight":{
"weight":"20322",
"prevWeight":"1000",
"prevTransaction":"1607680754361",
"transaction":"1607680754361",
"on":"false",
"transactionDataCount":"1",
"stable":"false",
"duration":"12",
"transactionMaxWeight":"2000",
"perimetr":"true",
"driverInCar":"false"
}
}';
apex_json.parse(tv,v_clob);
l_object := json_object_t.parse (v_clob);
l_key_list := l_object.get_keys;
FOR counter IN 1 .. l_key_list.COUNT
LOOP
obj_in_obj := l_object.get_object(l_key_list (counter));
l_key_obj := obj_in_obj.get_keys;
FOR counter_all_obj IN 1 .. l_key_obj.COUNT
LOOP
DBMS_OUTPUT.put_line (
l_key_list (counter)||'.'||l_key_obj (counter_all_obj)
|| ' : '
|| apex_json.get_varchar2(p_path => l_key_list (counter)||'.'|| l_key_obj (counter_all_obj), p_values => tv));
END LOOP;
END LOOP;
END;