Store Object with Arbitrary Properties in BigQuery -

i trying load data table in bigquery in 1 of fields needs hold json object arbitrary property names. since there limitless amount of property names have expect, predefining of property names in schema not option.

the data trying insert looks this:

{   property1: "randomstring",   property2: 128,   property3: {     randomnestedproperty1: "value1",     ...   } } 

where property3 named property3 yet can contain arbitrary amount of properties inside. how define schema object or create field hold property3 , of properties?

edit: should clarify every value in object property3 references string. i.e. there no nested objects in property3.