using json array to represent tables col>3
We are not not putting the tables with colum > 3 as json object rather using array

a b c d
1 2 3 4
5 6 7 8

will give json like:
[
{
    a:1,
    b:2,
    c:3,
    d:4
},
{
    a:5,
    b:6,
    c:7,
    d:8
}
]