这儿有一个**FastAPI**和**PostgreSQL**的官方项目生成器，全部基于**Docker**，包括前端和更多工具：<a href="https://github.com/tiangolo/full-stack-fastapi-postgresql" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-fastapi-postgresql</a>

///

/// note

请注意，大部分代码是`SQLAlchemy`的标准代码，您可以用于任何框架。FastAPI特定的代码和往常一样少。

///

## 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。

 * ```
 *
 * Clear the connection pool with [evictAll()][ConnectionPool.evictAll]. Note that the connection
 * pool's daemon thread may not exit immediately.
 *
 * ```java
 * client.connectionPool().evictAll();
 * ```
 *
 * If your client has a cache, call [close()][Cache.close]. Note that it is an error to create calls
 * against a cache that is closed, and doing so will cause the call to crash.
 *

**FastAPI** hoàn toàn được dựa trên những gợi ý kiểu dữ liệu, chúng mang đến nhiều ưu điểm và lợi ích.

Nhưng thậm chí nếu bạn không bao giờ sử dụng **FastAPI**, bạn sẽ được lợi từ việc học một ít về chúng.

/// note

Nếu bạn là một chuyên gia về Python, và bạn đã biết mọi thứ về gợi ý kiểu dữ liệu, bỏ qua và đi tới chương tiếp theo.

///

## Động lực

Hãy bắt đầu với một ví dụ đơn giản:

```Python

@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

**Note**

Si vous n'êtes pas familier avec cette notion, consultez la section _"Vous êtes pressés ?"_ à propos de <a href="https://fastapi.tiangolo.com/fr/async/#vous-etes-presses" target="_blank">`async` et `await` dans la documentation</a>.

// which in-turn heals the respective meta directory path and any files in int.
func (h *healSequence) healMinioSysMeta(objAPI ObjectLayer, metaPrefix string) func() error {
	return func() error {
		// NOTE: Healing on meta is run regardless
		// of any bucket being selected, this is to ensure that
		// meta are always upto date and correct.

		return defPool, noReadQuorumPools, nil
	}
	return PoolObjInfo{}, noReadQuorumPools, toObjectErr(errFileNotFound, bucket, object)
}

// return all pools with read quorum error or no error for an object with given opts.Note that this array is
// returned in the order of recency of object ModTime.
func (z *erasureServerPools) poolsWithObject(pools []PoolObjInfo, opts ObjectOptions) (errs []poolErrs) {
	for _, pool := range pools {

   *
   * <p>If the mapped elements contain duplicates (according to {@link Object#equals}), the element
   * will be added more than once, with the count summed over all appearances of the element.
   *
   * <p>Note that {@code stream.collect(toMultiset(function, e -> 1, supplier))} is equivalent to
   * {@code stream.map(function).collect(Collectors.toCollection(supplier))}.
   *
   * <p>To collect to an {@link ImmutableMultiset}, use {@link

   *
   * <p>If the mapped elements contain duplicates (according to {@link Object#equals}), the element
   * will be added more than once, with the count summed over all appearances of the element.
   *
   * <p>Note that {@code stream.collect(toMultiset(function, e -> 1, supplier))} is equivalent to
   * {@code stream.map(function).collect(Collectors.toCollection(supplier))}.
   *
   * <p>To collect to an {@link ImmutableMultiset}, use {@link

    👉 📁 **🚫 🔀 🛎**, ☁ 🔜 🔍 ⚫️ & ⚙️ **💾** 👉 🔁, 🛠️ 💾 ⏭ 🔁 💁‍♂️.

4️⃣. ❎ 📦 🔗 📄 📁.

     `--no-cache-dir` 🎛 💬 `pip` 🚫 🖊 ⏬ 📦 🌐, 👈 🕴 🚥 `pip` 🔜 🏃 🔄 ❎ 🎏 📦, ✋️ 👈 🚫 💼 🕐❔ 👷 ⏮️ 📦.

    /// note

    `--no-cache-dir` 🕴 🔗 `pip`, ⚫️ ✔️ 🕳 ⏮️ ☁ ⚖️ 📦.

    ///

     `--upgrade` 🎛 💬 `pip` ♻ 📦 🚥 👫 ⏪ ❎.

    ↩️ ⏮️ 🔁 🖨 📁 💪 🔍 **☁ 💾**, 👉 🔁 🔜 **⚙️ ☁ 💾** 🕐❔ 💪.

      return new ImmutableSortedMap<>(
          ImmutableSortedSet.emptySet(comparator), ImmutableList.<V>of());
    }
  }

  /**
   * Returns the empty sorted map.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  // unsafe, comparator() returns a comparator on the specified type