class DuckDB::Appender

.flush
.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'

data is invalidated, and this method raises DuckDB::Error.
If flushing the data triggers a constraint violation or any other error, then all
Flushes the appender to the table, forcing the cache of the appender to be cleared.

appender.flush -> self
:call-seq:

def flush
  return self if _flush
  raise_appender_error('failed to flush')
end