How to loop and insert data into different tables from JSON - postgresql

Question

I have a JSON and I need to write the values into different tables. I could get the data from json, but I need to insert the data accordingly. It's like I have a form, the form has n number of sections, each section have n number of steps and each step can have n number of questions. How I can loop this and write into different tables? Basically I need to know how we can find how many sections, steps and questions we have in the JSON. I tried array_length, but not working.
Here is a small sample of my JSON.
{ "functionId" : "2","subFunctionId" : "6","groupId" : "11","formId" : "","formName":"BladeInseption","submittedBy" : "200021669","createdDate" : "2015-08-06",
"updatedBy" : "","updatedDate" : "","comments" : "","formStatusId" :"11","formStatus" :"Draft","formLanguage" : "English","isFormConfigured" : "N","formChange":"Yes",
"sectionLevelChange":"Yes","isActive" : "Y","formVersionNo" : "1.0","formFooterDetails" : "","formHeaderDetails" : "","images" : [
{"imageId" : "","imageTempId" : "","imageTempUrl" : "","imageName" : "","imageUrl" : "","isDeleted" : "","imagesDesc" : ""} ],
"imagesDescLevel" : "","sectionElements" : [{"sectionElement":[{"sectionId" : "","sectionTempId":"sectionId+DDMMHHSSSS","sectionName":"section1",
"sectionChange":"Yes","stepLevelChange":"Yes","sectionLabel" : "","sectionOrder" : "1","outOfScopeSection" : "false",
"punchListSection" : "false","images" : [{"imageId" : "","imageTempId" : "","imageTempUrl" : "","imageName" : "","imageUrl" : "","isDeleted" : "",
"imagesDesc" : ""}],"imagesDescLevel" : "","isDeleted" : "","stepElements" : [{"stepElement":[{"stepId" : "","stepTempId":"stepId+DDMMHHSSSS",
"stepName":"section1step1","stepLabel" : "","stepOrder" : "1","stepChange":"Yes","questionLevelChange":"Yes","images" : [{"imageId" : "",
"imageTempId" : "","imageTempUrl" : "","imageName" : "","imageUrl" : "","isDeleted" : "","imagesDesc" : ""}],"imagesDescLevel" : "","isDeleted" : "",
"questionAnswerElements" : [{"questionAnswerElement":[{"questionId" : "","questionClientUid" : "","questionDescription" : "step1question1",
"questionAccessibility" : "","isPunchListQuestion" : "","questionChange":"Yes","questionOrder" : "1","isDeleted" : "","images" : [{
"imageId" : "","imageTempId" : "","imageTempUrl" : "","imageName" : "","imageUrl" : "","isDeleted" : "","imagesDesc" : ""}],"imagesDescLevel" : "",
"answerId" : "","answerClientUid" : "","elements" :[{"element" :[{"elementId": "2","elementMapId" : "12","clientUid" : "","clientClass" : "","imageTempId" : "",
"imageTempUrl" : "","elementType":"Question","elementOrder" : "1","elementArributuesProp": [{"attributeId" : "1","attributeName" : "","defaultValue" : ""}],
"elementArributuesVal":[{"value1" : "item1"}],"rule" : [{"ruleId" : "1","ruleName" : "Mandatory","formula" : "i>a","formulaData" : "i>50","isDeleted" : "",
...
}

Answer 1

If you know all paths to JSON arrays in your code, can use some special functions appearing in 9.4 such as
SELECT json_array_length('{"array":[{"a":1},{"b":2},{"c":3}]}'::json->'array')
If you need to iterate through JSON array, there is another useful function:
SELECT json_array_elements('{"array":[{"a":1},{"b":2},{"c":3}]}'::json->'array')
SELECT json_array_elements('[{"a":1},{"b":2},{"c":3}]'::json)
or if json is stored in table, lets call
SELECT json_array_elements(tbl.json_value->'array') FROM jsontable AS tbl
It returns a set of json values unwrapped from array ready to processing.
http://www.postgresql.org/docs/9.4/static/functions-json.html
More information about JSON parsing can be found here
How do I query using fields inside the new PostgreSQL JSON datatype?