书接上文，多个关联模型这种情况很常见。

特别是用户模型，因为：

* **输入模型**应该含密码
* **输出模型**不应含密码
* **数据库模型**需要加密的密码

/// danger | "危险"

千万不要存储用户的明文密码。始终存储可以进行验证的**安全哈希值**。

如果不了解这方面的知识，请参阅[安全性中的章节](security/simple-oauth2.md#password-hashing){.internal-link target=_blank}，了解什么是**密码哈希**。

///

## 多个模型

下面的代码展示了不同模型处理密码字段的方式，及使用位置的大致思路：

//// tab | Python 3.10+

```Python hl_lines="7  9  14  20  22  27-28  31-33  38-39"

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.collect.CollectPreconditions.checkPositive;
import static com.google.common.collect.Hashing.smearedHash;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Objects;
import com.google.common.base.Preconditions;

  val random: Random,
  private val perMessageDeflate: Boolean,
  private val noContextTakeover: Boolean,
  private val minimumDeflateSize: Long,
) : Closeable {
  /** This holds outbound data for compression and masking. */
  private val messageBuffer = Buffer()

  /** The [Buffer] of [sink]. Write to this and then flush/emit [sink]. */
  private val sinkBuffer: Buffer = sink.buffer
  private var writerClosed = false

   *
   * <p>Values do not have to be unique. However, values must be non-null.
   *
   * <p>If either or both endpoints are not already present in this graph, this method will silently
   * {@link #addNode(Object) add} each missing endpoint to the graph.
   *
   * @return the value previously associated with the edge connecting {@code nodeU} to {@code
   *     nodeV}, or null if there was no such edge.

			expectedErr: errors.New("MasterKeyID is missing with aws:kms"),
			shouldPass:  false,
		},
		// 6. Invalid Algorithm
		{

* <abbr title="also known as: serialization, parsing, marshalling">Conversion</abbr> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

* <abbr title="also known as: serialization, parsing, marshalling">Conversion</abbr> of input data: coming from the network to Python data and types. Reading from:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Forms.
    * Files.

)

// SelectStatement is the top level parsed and analyzed structure
type SelectStatement struct {
	selectAST *Select

	// Analysis result of the statement
	selectQProp qProp

	// Result of parsing the limit clause if one is present
	// (otherwise -1)
	limitValue int64

	// Count of rows that have been output.
	outputCount int64

	// Table alias
	tableAlias string
}

import java.util.StringTokenizer;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.context.SingletonContext;


/**
 * This class now contains only utilities for config parsing.
 * 
 * We strongly suggest that you create an explicit {@link jcifs.context.CIFSContextWrapper}
 * with your desired config. It's base implementation {@link jcifs.context.BaseContext}
 * should be sufficient for most needs.

                return false;
            }
        }

        if ( !foundPreauth ) {
            log.error("Missing preauth negotiate context");
            return false;
        }
        if ( !foundEnc && ( caps & Smb2Constants.SMB2_GLOBAL_CAP_ENCRYPTION ) != 0 ) {
            log.error("Missing encryption negotiate context");
            return false;
        }
        else if ( !foundEnc ) {