I created a delta table through a cluster over a dbfs location .

Schema :

create external table tmp_db.delta_data(

delta_id int ,

delta_name varchar(20) ,

delta_variation decimal(10,4) ,

delta_incoming_timestamp timestamp,

delta_date date generated always as (cast (split(cast(delta_incoming_timestamp as string),' ')[0] as date)) comment 'Generated', -- cound use date(col)

delta_time string generated always as (cast(split(cast(split(cast(delta_incoming_timestamp as string),' ')[1] as string),'\\.')[0] as string)) comment 'Generated',

delta_milliseconds string generated always as (cast(split(cast(split(cast(delta_incoming_timestamp as string),' ')[1] as string),'\\.')[1] as string)) comment 'Generated'

) 

using delta 

partitioned by (delta_date)

location 'dbfs:/tmp/tables_base/tmp_db/delta_data';

It got created for the first time. I inserted few rows into the table.

I dropped the table as it is a external table and created the table in another databricks cluster. I'm getting the below error.

```

== Specified ==

root

-- delta_id: integer (nullable = true)

-- delta_name: varchar(20) (nullable = true)

-- delta_variation: decimal(10,4) (nullable = true)

-- delta_incoming_timestamp: timestamp (nullable = true)

-- delta_date: date (nullable = true)

-- delta_time: string (nullable = true)

-- delta_milliseconds: string (nullable = true)

== Existing ==

root

-- delta_id: integer (nullable = true)

-- delta_name: string (nullable = true)

-- delta_variation: decimal(10,4) (nullable = true)

-- delta_incoming_timestamp: timestamp (nullable = true)

-- delta_date: date (nullable = true)

-- delta_time: string (nullable = true)

-- delta_milliseconds: string (nullable = true)

== Differences==

- Specified metadata for field delta_name is different from existing schema:

Specified: {}

Existing: {"__CHAR_VARCHAR_TYPE_STRING":"varchar(20)"}

- Specified type for delta_name is different from existing schema:

Specified: varchar(20)

Existing: string

```

I don't understand why this metadata got added to a varchar column and why the varchar column got saved as string. And If it is a default behavior , How can I specify the config {"__CHAR_VARCHAR_TYPE_STRING":"varchar(20)"} for that particular column ?