class DuckDB::Appender

.close
.end_row
.append_varchar('Alice')
.append_int32(1)
appender
appender = con.appender('users')
con.query('CREATE TABLE users (id INTEGER, name VARCHAR)')
con = db.connect
db = DuckDB::Database.open
require 'duckdb'

invalidated, and this method raises DuckDB::Error.
If flushing the data triggers a constraint violation or any other error, then all data is
Closes the appender by flushing all intermediate states and closing it for further appends.

appender.close -> self
:call-seq:

def close
  return self if _close
  raise_appender_error('failed to close')
end