Scival REST API to database table for analysis - JSON Path - oracle

Question

I'm trying to get some specific dataset from Scival REST API to oracle database table. Below is the JSON payload that I'm trying to manipulate.
{
"metrics": [{
"metricType": "ScholarlyOutput",
"valueByYear": {
"2017": 4,
"2018": 0,
"2019": 3,
"2020": 1,
"2021": 1
}
}],
"author": {
"link": {
"#ref": "self",
"#href": "https://api.elsevier.com/analytics/scival/author/123456789?apiKey=xxxxxxxxxx&httpAccept=text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2",
"#type": "text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2"
},
"name": "Citizen, John",
"id": 123456789,
"uri": "Author/123456789"
}
}
I'm able to query the 'author' bit with the below SQL.
SELECT jt.*
FROM TABLE d,
JSON_TABLE(d.column format json, '$.author' COLUMNS (
"id" VARCHAR2 PATH '$.id',
"name" VARCHAR2 PATH '$.name')
) jt;
However, I'm not able to get the 'valueByYear' value. I've tried below.
SELECT jt.*
FROM TABLE d,
JSON_TABLE
(d.column, '$.metrics[*]' COLUMNS
(
"metric_Type" VARCHAR2 PATH '$.metricType'
,"Value_By_Year" NUMBER PATH '$.valueByYear'
NESTED PATH '$.valueByYear[1]' COLUMNS
("2021" NUMBER PATH '$.valueByYear[1]'
)
)
) jt;
I would appreciate if you could let me know what I'm missing here. I'm after the latest 'year' value.

Answer 1

You can use:
SELECT jt.*
FROM table_name d,
JSON_TABLE(
d.column_name format json,
'$'
COLUMNS (
id VARCHAR2 PATH '$.author.id',
name VARCHAR2 PATH '$.author.name',
NESTED PATH '$.metrics[*]' COLUMNS (
metricType VARCHAR2(30) PATH '$.metricType',
value2021 NUMBER PATH '$.valueByYear."2021"'
)
)
) jt;
Which, for the sample data:
CREATE TABLE table_name (
column_name CLOB CHECK (column_name IS JSON)
);
INSERT INTO table_name (column_name) VALUES (
'{
"metrics": [{
"metricType": "ScholarlyOutput",
"valueByYear": {
"2017": 4,
"2018": 0,
"2019": 3,
"2020": 1,
"2021": 1
}
}],
"author": {
"link": {
"#ref": "self",
"#href": "https://api.elsevier.com/analytics/scival/author/123456789?apiKey=xxxxxxxxxx&httpAccept=text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2",
"#type": "text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2"
},
"name": "Citizen, John",
"id": 123456789,
"uri": "Author/123456789"
}
}'
);
Outputs:
ID
NAME
METRICTYPE
VALUE2021
123456789
Citizen, John
ScholarlyOutput
1
db<>fiddle here

Answer 2

If you want to do it dynamically in PL/SQL, then you can create the types:
CREATE TYPE scival_row IS OBJECT(
name VARCHAR2(100),
id NUMBER(12),
metricType VARCHAR2(50),
year NUMBER(4),
value NUMBER
);
CREATE TYPE scival_tbl IS TABLE OF scival_row;
and then the pipelined function:
CREATE FUNCTION parseScival(
i_json CLOB,
i_year NUMBER
) RETURN scival_tbl PIPELINED DETERMINISTIC
IS
v_obj JSON_OBJECT_T := JSON_OBJECT_T.parse(i_json);
v_author JSON_OBJECT_T := v_obj.get_Object('author');
v_name VARCHAR2(100) := v_author.get_String('name');
v_id NUMBER(12) := v_author.get_Number('id');
v_metrics JSON_ARRAY_T := v_obj.get_Array('metrics');
v_metric JSON_OBJECT_T;
BEGIN
FOR i IN 0 .. v_metrics.Get_Size - 1 LOOP
v_metric := TREAT(v_metrics.get(i) AS JSON_OBJECT_T);
PIPE ROW(
scival_row(
v_name,
v_id,
v_metric.get_string('metricType'),
i_year,
v_metric.get_object('valueByYear').get_number(i_year)
)
);
END LOOP;
END;
/
Then you can use the query:
SELECT j.*
FROM table_name t
CROSS APPLY TABLE(parseScival(t.column_name, 2021)) j
Which outputs:
NAME
ID
METRICTYPE
YEAR
VALUE
Citizen, John
123456789
ScholarlyOutput
2021
1
db<>fiddle here