Delphi: Accessing JSON Objects within a JSON Array

Question

I have a JSON Object, let's name it jObject that looks like this:

{
  "id": 0,
  "data": "[{DAT_INCL: \"08/03/2012 10:07:08\", NUM_ORDE: 1, NUM_ATND: 1, NUM_ACAO: 2, NUM_RESU: 3},
            {DAT_INCL: \"08/03/2012 10:07:09\", NUM_ORDE: 2, NUM_ATND: 1, NUM_ACAO: 4, NUM_RESU: 5},
            {DAT_INCL: \"08/03/2012 10:07:09\", NUM_ORDE: 3, NUM_ATND: 1, NUM_ACAO: 8, NUM_RESU: NULL}]"
}

As you can see, it contains two pairs, one of which is an array with three objects in this case (the amount of objects is dynamic) with multiple "key: values"(these don't vary, being always the same 5 fields), which I want to insert into an SQL database, "key" being column, "value" being field. Question is, how do I access each object individually?

Code-wise what I did was extract the pair that contained this array by putting it in jPair

jPair := OriginalObject.Get(1); 

and then captured the array

jArray:= TJSONArray(jPair.JsonValue);

(Also, as a bonus, when I evaluate jArray.Size, the result is 6226004. What?)

Answer 1

If you have an array from DBXJSON, then it is a TJSONArray. Call its Get method to get an element of the array.

var
  Value: TJSONValue;

Value := jArray.Get(0);

You can also go through the entire array with a for loop:

for Value in jArray do

---

But if you check the Size property and get 6226004 instead of 3, that suggests there's something else wrong here. My guess is that what you think is a TJSONArray isn't really that type. Use as to do a checked type cast:

jArray := jPair.JsonValue as TJSONArray;

You'll get an EInvalidCast exception if that fails.