首先，請先建立你的[虛擬環境](../virtual-environments.md)、啟用它，然後安裝 `sqlmodel`：

<div class="termy">

```console
$ pip install sqlmodel
---> 100%
```

</div>

## 建立只有單一模型的應用 { #create-the-app-with-a-single-model }

我們先用單一 SQLModel 模型建立這個應用的最簡版。

接著我們會在下方用多個模型來提升安全性與彈性。🤓

### 建立模型 { #create-models }

匯入 `SQLModel` 並建立一個資料庫模型：

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[1:11] hl[7:11] *}

  //
  // class Entry {
  //    int hash;
  //    Entry next;
  //    K key;
  //    V value;
  // }
  //
  // The imaginary `hash` and `next` values are combined into a single `int` value in the `entries`
  // array. The top bits of this value are the remaining bits of the hash value that were not used
  // in the short hash. We saw that a mask of 0x7f would keep the 7-bit value 0x6f from a full

まずは [仮想環境](../virtual-environments.md) を作成・有効化し、`sqlmodel` をインストールします:

<div class="termy">

```console
$ pip install sqlmodel
---> 100%
```

</div>

## 単一モデルでアプリ作成 { #create-the-app-with-a-single-model }

まずは最も簡単な、単一の SQLModel モデルだけを使うバージョンを作ります。

後で、下記のとおり複数モデルにしてセキュリティと汎用性を高めます。🤓

### モデルの作成 { #create-models }

`SQLModel` をインポートしてデータベースモデルを作成します:

   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this
  static final int DRAIN_MAX = 16;

  // Fields

  /**

      builder.add(new LocationInfo(entry.getKey(), entry.getValue()));
    }
    return builder.build();
  }

  /**
   * Represents a single location (a directory or a jar file) in the class path and is responsible
   * for scanning resources from this location.
   */
  static final class LocationInfo {
    final File home;

  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableSetMultimap<K, V> of() {
    return (ImmutableSetMultimap<K, V>) EmptyImmutableSetMultimap.INSTANCE;
  }

  /** Returns an immutable multimap containing a single entry. */
  public static <K, V> ImmutableSetMultimap<K, V> of(K k1, V v1) {
    ImmutableSetMultimap.Builder<K, V> builder = ImmutableSetMultimap.builder();
    builder.put(k1, v1);
    return builder.build();
  }

   * @since 19.0 (since 1.0 as constant {@code INVISIBLE})
   */
  @Deprecated
  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *

- DRA device taint eviction: the controller might have reported "1 pod needs to be evicted in 1 namespace. 1 pod evicted since starting the controller." when only a single pod is involved, depending on timing (pod evicted, informer...

    return (ImmutableSortedMap<K, V>) NATURAL_EMPTY_MAP;
  }

  /** Returns an immutable map containing a single entry. */
  public static <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V> of(K k1, V v1) {
    return of(Ordering.natural(), k1, v1);
  }

  /** Returns an immutable map containing a single entry. */
  private static <K, V> ImmutableSortedMap<K, V> of(Comparator<? super K> comparator, K k1, V v1) {

   *
   * <p>If the {@link File} passed to one of the {@link Traverser} methods does not exist or is not
   * a directory, no exception will be thrown and the returned {@link Iterable} will contain a
   * single element: that file.
   *
   * <p>Example: {@code Files.fileTraverser().depthFirstPreOrder(new File("/"))} may return files
   * with the following paths: {@code ["/", "/etc", "/etc/config.txt", "/etc/fonts", "/home",