# Changing data formats

In this example, we will show how to create an AVRO topic from an existing JSON topic.

## Requirements <a href="#requirements" id="requirements"></a>

For this to work, Lenses has to know what the source topic schema is. Lenses can do this in one of three ways:

* through direct user action where the schema is manually set
* through inference; Lenses will try to infer the schema of a topic by looking at the topic data
* and lastly, if the topic is created through Lenses, the schema will be automatically set

## Creating the JSON data <a href="#creating-the-json-data" id="creating-the-json-data"></a>

With the following SQL we can create our intial JSON topic:

```sql
CREATE TABLE car_speed_events_json(
    _key.plate string
    , speedMph int
    , sensor.id string
    , sensor.lat double
    , sensor.long double
    , event_time long
)
FORMAT (json, json);
```

to which we can add data using:

```sql
INSERT INTO car_speed_events_json (
    _key.plate
    , speedMph
    , sensor.id 
    , sensor.lat
    , sensor.long 
    , event_time 
) VALUES
("20-GH-38", 50, "sensor_1", 45.1241, 1.177, 1591970345),
("20-VL-12", 30, "sensor_1", 45.1241, 1.177, 1591970345),
("20-JH-98", 90, "sensor_1", 45.1241, 1.177, 1591970345);
```

It can be quickly verified that the format of our newly created topic is JSON for both key and value by searching our topic `car_speed_events_json` in our explore view:

## Creating the AVRO topic <a href="#creating-the-avro-topic" id="creating-the-avro-topic"></a>

To create a new topic with format AVRO, we can create a processor that will copy the data from our original topic to a new topic changing the format in the process.

To do this, we start by going to “SQL Processor”, clicking: **“New SQL Processor”** and defining our processor with the following code:

```sql
SET defaults.topic.autocreate=true;

INSERT INTO car_speed_events_avro
STORE 
    KEY AS AVRO 
    VALUE AS AVRO
SELECT STREAM *
FROM car_speed_events_json;
```

Notice the addition of `STORE KEY AS AVRO VALULE AS AVRO`. This statement will tell our processor which format we want each facet (key or value) to be stored as.

Hitting “Create New Processor” will start a new processor

We can see the events were added and from now on, Lenses will keep pushing any new events added to `car_speed_events_avro` into `car_speed_events_avro`.

We can also verify that the topic format of our new topic is also AVRO for both the key and value facets: