SQLite3 gem中的类型转换有什么作用？

Question

gem的网站上没有记录初始化方法中的

type_translation = true。它做了什么？

Answer 1

从此链接：https://github.com/sparklemotion/sqlite3-ruby/blob/master/lib/sqlite3/database.rb

＆＃34; ... Database类也提供类型转换服务，SQLite3数据类型（全部表示为字符串）可以通过它转换为相应的类型（如表中的模式中所定义） ）。此查询仅在从数据库查询数据时发生 - 插入和更新仍然是无类型的...＆＃34;

这也可能有所帮助：https://sqlite.org/datatype3.html因为它解释了如何在sqlite3中处理数据类型。

Answer 2

答案可以在examining the source code找到：

# Return the type translator employed by this database instance. Each
# database instance has its own type translator; this allows for different
# type handlers to be installed in each instance without affecting other
# instances. Furthermore, the translators are instantiated lazily, so that
# if a database does not use type translation, it will not be burdened by
# the overhead of a useless type translator. (See the Translator class.)

当您查看Translator class：

时

# The Translator class encapsulates the logic and callbacks necessary for
# converting string data to a value of some specified type. Every Database
# instance may have a Translator instance, in order to assist in type
# translation (Database#type_translation).

因此，当type_translation = true时，sqlite3将使用该数据库的类型转换器来协助在数据类型之间序列化数据。