mind the character limit when generating table names

[rudolfix]

when table names are composed of several components (which correspond to the elements in nested json) we can easily cross the 255 chat limit of ext filesystem or table name length limit of a particular db.

1. prevent creating component table names longer than x characters: ie. 20 chars max and then 6 chars of hash
2. prevent creating full table names longer than 200 chars. if this is exceeded then: root_table__depth_hash__parent_table__child_table where depth replaces all the inner tables (depth: number of replaces tables, hash: some hash on replaced content)

[rudolfix]

example limits

• postgres, mysql: 63 chars
• redshift: 127 chars
• bigquery: 320 chars

[rudolfix]

ad 2. the length would be configurable so the trim function can be used to create file names and and database names

in case of both the original file name may be retrieved by reverse lookup in the table list in the schema: each name is trimmed to desired length and then compared to the name we look for

[rudolfix]

closed by #157