With an ORM, you normally create a class that represents a table in a SQL database, each attribute of the class represents a column, with a name and a type.

For example a class `Pet` could represent a SQL table `pets`.

And each *instance* object of that class represents a row in the database.

## ORMs（对象关系映射）

**FastAPI**可与任何数据库在任何样式的库中一起与 数据库进行通信。

一种常见的模式是使用“ORM”：对象关系映射。

ORM 具有在代码和数据库表（“*关系型”）中的**对象**之间转换（“*映射*”）的工具。

使用 ORM，您通常会在 SQL 数据库中创建一个代表映射的类，该类的每个属性代表一个列，具有名称和类型。

例如，一个类`Pet`可以表示一个 SQL 表`pets`。

该类的每个*实例对象都代表数据库中的一行数据。*

又例如，一个对象`orion_cat`（`Pet`的一个实例）可以有一个属性`orion_cat.type`, 对标数据库中的`type`列。并且该属性的值可以是其它，例如`"cat"`。

这些 ORM 还具有在表或实体之间建立关系的工具（比如创建多表关系）。

**FastAPI** 👷 ⏮️ 🙆 💽 & 🙆 👗 🗃 💬 💽.

⚠ ⚓ ⚙️ "🐜": "🎚-🔗 🗺" 🗃.

🐜 ✔️ 🧰 🗜 ("*🗺*") 🖖 *🎚* 📟 & 💽 🏓 ("*🔗*").

⏮️ 🐜, 👆 🛎 ✍ 🎓 👈 🎨 🏓 🗄 💽, 🔠 🔢 🎓 🎨 🏓, ⏮️ 📛 & 🆎.

🖼 🎓 `Pet` 💪 🎨 🗄 🏓 `pets`.

& 🔠 *👐* 🎚 👈 🎓 🎨 ⏭ 💽.

🖼 🎚 `orion_cat` (👐 `Pet`) 💪 ✔️ 🔢 `orion_cat.type`, 🏓 `type`. & 💲 👈 🔢 💪, ✅ `"cat"`.

👫 🐜 ✔️ 🧰 ⚒ 🔗 ⚖️ 🔗 🖖 🏓 ⚖️ 👨‍💼.

   * It is set by a client who only wants to make a request if it can be fully satisfied by the
   * cache. Cached responses that would require validation (ie. conditional gets) are not permitted
   * if this header is set.
   */
  @get:JvmName("onlyIfCached") val onlyIfCached: Boolean,
  @get:JvmName("noTransform") val noTransform: Boolean,
  @get:JvmName("immutable") val immutable: Boolean,

- *If total drives has many common divisors the algorithm chooses the minimum amounts of erasure sets possible for a erasure set size of any N*.  In the example with 1024 drives - 4, 8, 16 are GCD factors. With 16 drives we get a total of 64 possible sets, with 8 drives we get a total of 128 possible sets, with 4 drives we get a total of 256 possible sets. So algorithm automatically chooses 64 sets, which is *16* 64 = 1024* drives in total.

MinIO in distributed mode lets you pool multiple drives (even on different machines) into a single object storage server. As drives are distributed across several nodes, distributed MinIO can withstand multiple node failures and yet ensure full data protection.

    supported on Android, Java, or Conscrypt.

    We removed this cipher suite and `TLS_AES_128_CCM_SHA256` from the restricted, modern, and
    compatible sets of cipher suites. These two cipher suites aren't enabled by default in either
    Firefox or Chrome.

    See our [TLS Configuration History][tls_configuration_history] tracker for a log of all changes

      }

    /**
     * Sets the URL target of this request.
     *
     * @throws IllegalArgumentException if [url] is not a valid HTTP or HTTPS URL. Avoid this
     *     exception by calling [HttpUrl.parse]; it returns null for invalid URLs.
     */
    open fun url(url: String): Builder {
      return url(canonicalUrl(url).toHttpUrl())
    }

    /**
     * Sets the URL target of this request.
     *

    }
  }

  /**
   * This test reproduces a crash where OkHttp attempted to use a deferred connection when the call
   * already had a healthy connection. It sets up a deferred connection by stalling the IPv6
   * connect, and it sets up a same-connection retry with [ErrorCode.REFUSED_STREAM].
   *
   * https://github.com/square/okhttp/pull/7190
   */
  @Test
  fun preferCallConnectionOverDeferredConnection() {

FIELD com.google.common.collect.ImmutableRangeSet.ranges
FIELD com.google.common.collect.ImmutableSet.asList
FIELD com.google.common.collect.Maps.FilteredMapValues.unfiltered
FIELD com.google.common.collect.Sets.SubSet.inputSet
FIELD com.google.common.collect.SingletonImmutableBiMap.inverse
FIELD com.google.common.collect.TreeTraverser.PostOrderNode.childIterator
FIELD com.google.common.collect.TreeTraverser.PreOrderIterator.stack