FlattenSchema

SQL

When you import tables with variant data into Prophecy, they become columns with nested columns, and a variant data type, which is an array of values with more than one data type.

You can use the FlattenSchema gem to transform your variant schema into a more consistent and digestible format. This allows your team to make subsequent steps in the pipeline more efficient and streamlined. This also makes your variant data easier to analyze, report, and integrate traditional systems without doing this manually yourself.

Parameters

Parameter	Description	Required
Flatten	Array column to flatten for each Output Column.	True
Expressions	Expression to compute each field in the Output Column.	True

Example

Assume you have the following JSON file that includes variant data type that you would like to flatten.

[{
  "first_name":"Remmington", "last_name":"Smith", "age":"68",
  "business":[{
    "address":[{
      "manager":"Liara Andrew", "name":"RS Enterprises",
      "contact":[{"content":"rsmith@example.com","type":"email"},{"content":"1234-345-56","type":"phone"}],
      "is_still_active":false}]}]}, {
  "first_name":"Penny", "last_name":"John", "age":"57",
  "business":[{
    "address":[{
      "manager":"Bobby Frank","name":"PJ Enterprises",
      "contact":[{"content":"pjohn@example.com","type":"email"},{"content":"8203-512-49","type":"phone"}],
      "is_still_active":true}]}]}]

Expressions

The FlattenSchema gem allows you to extract variant data into a flattened schema.

For example, to flatten your variant data:

1. In the Input tab, hover over the in0 field and click the Add 12 Columns button.

   Now, all the nested lowest-level values of your object are visible as columns in the Expressions section.

   

2. (Optional) To change the name of the column in the output, change the value in the Output Column for the row.

3. Click Run.

Output

After you run the FlattenSchema gem, click the Data button to see your schema based on the selected columns:

The FlattenSchema gem flattened all your variant data, which gives you individual rows for each one.

Snowflake advanced settings

You can use advanced settings with your Snowflake source to customize the optional column arguments.

To use the advanced settings:

1. Hover over the column you want to flatten.

2. Click the dropdown arrow.

   You can customize the following options:

   Option	Description	Default
   Path to the element	Path to the element within the variant data structure that you want to flatten.	None
   Flatten all elements recursively	Whether to expand all sub-elements recursively.	false
   Preserve rows with missing field	Whether to include rows with missing fields as null in the key, index, and value columns.	false
   Datatype that needs to be flattened	Data type that you want to flatten. Possible values are: Object, Array, or Both.	Both