Ruby: SQLite3 insert binary

gistfile1.rb

require "sqlite3"

db = SQLite3::Database.new("test.sqlite3")

sql = <<SQL
  create table test(
    content blob
  )
SQL
db.execute_batch(sql)

binary = File.open("test.pdf", "rb").read
db.execute("insert into test (content) values(?)", SQLite3::Blob.new(binary))

res = db.execute("select content from test")
File.open("res2.pdf", "wb").write(res[0][0])
p res[0][0].size