## CRUD工具

现在让我们看看文件`sql_app/crud.py`。

在这个文件中，我们将编写可重用的函数用来与数据库中的数据进行交互。

**CRUD**分别为：增加（**C**reate）、查询（**R**ead）、更改（**U**pdate）、删除（**D**elete），即增删改查。

...虽然在这个例子中我们只是新增和查询。

### 读取数据

从 `sqlalchemy.orm`中导入`Session`，这将允许您声明`db`参数的类型，并在您的函数中进行更好的类型检查和完成。

导入之前的`models`（SQLAlchemy 模型）和`schemas`（Pydantic*模型*/模式）。

创建一些工具函数来完成：

          "vres&cisab,lautriv,??ial.sppa,?s&codehtdaer,gnihtbew,nemeis-om,pparevelc,t&acdnas,ekcit,??t&e&kcubtib,notorp,?i&belet,detfihs,gude,kecaps,?raedon.egats,s&etwolfbew,udgniht.&cersid.&dvreser,tsuc,?dorp.tsuc,gnitset.&dvreser,tsuc,?ved.&dvreser,tsuc,????vgib.0ku,w&hs,olfbew,?x&bdrym,cq,rotide,?y&olpedew,srab,??b?d&ar?u&a?ts???j?r?syhp??j!.&eman?gro?hcs?lim?moc?ten?ud...

          "vres&cisab,lautriv,??ial.sppa,?s&codehtdaer,gnihtbew,nemeis-om,pparevelc,t&acdnas,ekcit,??t&e&kcubtib,notorp,?i&belet,detfihs,gude,kecaps,?raedon.egats,s&etwolfbew,udgniht.&cersid.&dvreser,tsuc,?dorp.tsuc,gnitset.&dvreser,tsuc,?ved.&dvreser,tsuc,????vgib.0ku,w&hs,olfbew,?x&bdrym,cq,rotide,?y&olpedew,srab,??b?d&ar?u&a?ts???j?r?syhp??j!.&eman?gro?hcs?lim?moc?ten?ud...

		{
			[]CompletePart{
				{ETag: fmt.Sprintf("\"\"\"\"\"%s\"\"\"", validPartMD5), PartNumber: 5},
			},
		},
		// inputParts - 4.
		// Used to verify that the other remaining parts are deleted after
		// a successful call to CompleteMultipartUpload.
		{
			[]CompletePart{
				{ETag: validPartMD5, PartNumber: 6},
			},
		},
	}
	s3MD5 := getCompleteMultipartMD5(inputParts[3].parts)

        return next;
      }

      @Override
      public String toString() {
        return "Iterators.consumingIterator(...)";
      }
    };
  }

  /**
   * Deletes and returns the next value from the iterator, or returns {@code null} if there is no
   * such value.
   */
  @CheckForNull
  static <T extends @Nullable Object> T pollNext(Iterator<T> iterator) {

    silently leak connections when an interceptor retries without closing the response body. With
    3.14 we detect this problem but the exception was not helpful.

## Version 3.14.0

_2019-03-14_

 *  **This release deletes the long-deprecated `OkUrlFactory` and `OkApacheClient` APIs.** These
    facades hide OkHttp's implementation behind another client's API. If you still need this please

continue to comply in full to this Library. If you modify this Library, you
may apply this exception to your version of this Library, but you are not
obliged to do so. If you do not wish to do so, delete this exception
statement from your version. This exception does not (and cannot) modify any
license terms which apply to the Application, with which you must still
comply.

            <p><strong>Warning:</strong> This is an internal utility property that is only public for technical reasons,
            it is not part of the public API. In particular, this property can be changed or deleted without prior
            notice.</p>
            ]]>
          </description>
        </field>
        <field>
          <name>goals</name>
          <version>4.0.0+</version>

tours

// town : 2014-03-06 Binky Moon, LLC
town

// toyota : 2015-04-23 TOYOTA MOTOR CORPORATION
toyota

// toys : 2014-03-06 Binky Moon, LLC
toys

// trade : 2014-01-23 Elite Registry Limited
trade

// trading : 2014-12-11 Dog Beach, LLC
trading

// training : 2013-11-07 Binky Moon, LLC
training

// travel : 2015-10-09 Dog Beach, LLC
travel