SQL Server: Update table based on JSON - sql

Question

I am trying to update rows in table based on JSON I have. JSON has the following structure:
"sensors": [
{
"id": "5afd7160f16819f11814f6e2",
"num": 0,
"name": "AC01",
"enabled": true,
"unit": "Volt AC Phase 1",
"desc": "NAMsdafE",
"lt_disaster": 1,
"gt_disaster": 1,
"lt_high": 1,
"gt_high": 1,
"lt_average": 1,
"gt_average": 1
},...
Table dbo.sensors has same structure + few more columns. To insert such JSON object, not array, into table, I would do it this way:
INSERT INTO dbo.sensors (.......)
SELECT .......
FROM OPENJSON(#json)
WITH (
id varchar(200),
....
);
So I have 2 questions: how to iterate over each element in JSON array and update each row with the same id. Any help would be appreciated:)

Answer 1

1) once you change the json into a select statement, you can iterate over that using cursor.
2) you can treat json select statement as a table. That said, you can do insert, update, delete operations exactly as you do with two tables. For updated case you can use code like this:
With Json_data as
( SELECT .......
FROM OPENJSON(#json)
WITH (
id varchar(200),
....
)
update S set ....
from dbo.sensors as S
inner join Json_data as JD on JD.id = S.id

Answer 2

First, read documentation OPENJSON. This feature is available starting version 2016.
Next, apply new knowledge.
--truncated for shortness
--note: wrap JSON string in curly brackets {}
declare #json nvarchar(max)='{"sensors":[
{
"id": "5afd7160f16819f11814f6e2",
"num": 0,
"name": "AC01",
"more": "unused"
},
{ "id": "5afd7160f16819f11814f6e3",
"num": 0,
"name": "AC02"
}]}
'
--insert...
select * from
openjson(#json,'$.sensors') --note the "path" argument here
with(
id varchar(200),
num int,
name varchar(10)
) json --alias sometimes required.
You can use result (rowset) as it is a table.

Answer 3

;With Json_data as
( SELECT
Evaluation_IDNO,
Rating_IDNO,
Notes_TEXT,
NextSteps_TEXT,
EvaluationCategory_CODE,
EvalType_ID
FROM OPENJSON(#As_EvaluationCategory_Json) WITH
(
Evaluation_IDNO INT N'$.matrixId',
Rating_IDNO VARCHAR(150) N'$.ratingValue',
Notes_TEXT VARCHAR(MAX) N'$.notesText',
NextSteps_TEXT VARCHAR(MAX) N'$.nextStepsText',
EvaluationCategory_CODE VARCHAR(50) N'$.ratingData',
EvalType_ID VARCHAR(4) N'$.evalTypeId'
)
AS EvaluationCategories
)
UPDATE EvaluationRatings_T1 SET
UserCreatedBy_ID=#As_SignedOnWorker_ID,
User_ID=#Ls_User_Id,
WorkspaceCreatedBy_ID=#Ls_WorkspaceCreatedBy_Id,
BeginValidity_DTTM=#Ls_Evaluation_DTTM,
EndValidity_DTTM=#Ld_HighValidity_DTTM,
TransactionEvenSeq_NUMB=#An_TransactionEventSeq_NUMB,
Update_DTTM=#Ld_BeginValiditiy_DTTM,
WorkspaceUpdatedBy_ID=#Ls_WorkspaceUpdatedBy_ID,
Evaluation_IDNO=c1.Evaluation_IDNO,
Rating_IDNO=c1.Rating_IDNO,
Notes_TEXT=c1.Notes_TEXT,
NextSteps_TEXT=c1.NextSteps_TEXT,
EvaluationCategory_CODE=c1.EvaluationCategory_CODE,
EvalType_ID=c1.EvalType_ID
FROM Json_data c1
inner JOIN EvaluationRatings_T1 e1 on e1.Evaluation_IDNO=c1.Evaluation_IDNO
WHERE e1.Evaluation_IDNO=#AS_Evaluation_IDNO;