### TODO
- support for *
- add support for set setting value
- command line interface
- date functions - now, add_date...
- support for order by, offset, limit (allow column name in order by, validate)
- add count min and max functions, eg aggregate functions
- support for uniqueue indexes (primary key)
- support for btree indexes
- support for parenthesis
- functions rtrim, ltrim, rpad, lpad
- add pipe | token
- maybe to create iterator on table
- class members should have prefix m_
- add const wherever should be