# DB Cache 使用與活用

## 如何裝入獨家數據並添加新數據

[**壟斷加載**](/proudnet.cn/proudnet/db_system/db_cache_ver2/theory.md#undefined)方法爲 <mark style="color:orange;">Proud.CDbCacheClient2.RequestExclusiveLoadData</mark> 。 您需要在參數 <mark style="color:orange;">fieldName</mark> 和 <mark style="color:orange;">cmpValue</mark> 中輸入查找條件以查找要加載的數據 。<br>

使用示例 。

```cpp
Proud::Guid outSessetionGuid;
Proud::CDbCacheClient2* c = ...;
c->RequestExclusiveLoadData(L"Gamer",L"GamerID",gamername,outSessetionGuid);
```

<mark style="color:orange;">Proud.CDbCacheClient2.RequestExclusiveLoadNewData</mark>方法同樣是專有裝入函數， 但在將數據添加到 RootTable 後立即寫入 。<br>

使用示例 。

```cpp
CPropNodePtr newNode = CPropNodePtr(new CPropNode(L"Gamer"));
 
newNode->Fields[L"GamerID"] = "Ulelio";
 
Proud::Guid outSessetionGuid;
Proud::CDbCacheClient2* c = ...;
c->RequestExclusiveLoadNewData(L"Gamer", newNode, outSessetionGuid);
```

## 單方面更改數據

> * Proud.CDbCacheClient2.UnilateralAddData
> * Proud.CDbCacheClient2.UnilateralUpdateData
> * Proud.CDbCacheClient2.UnilateralRemoveData

這些方法在DB cache存儲器中反映變更,之後在DBMS上以異步實際記錄,呼叫後立即返回。 此外，沒有回覆方法。

## 使用DBMS中首先反映的請求應答型方法和blocked方法

首先反映在DBMS上的請求響應方法和Blocked方法的使用是[**更改請求響應數據**](/proudnet.cn/proudnet/db_system/db_cache_ver2/theory.md#id-2)的方法。 呼叫後立即返回,變更只有在實際DBMS上完成記錄後,才能在DB cache的內存中反映出來。

<table data-full-width="false"><thead><tr><th width="294">呼叫方法</th><th>結果回撥</th></tr></thead><tbody><tr><td>Proud.CDbCacheClient2.RequestAddData</td><td>Proud.IDbCacheClientDelegate2.OnAddDataFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnAddDataSuccess</td></tr><tr><td>Proud.CDbCacheClient2.RequestUpdateData</td><td>Proud.IDbCacheClientDelegate2.OnUpdateDataFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnUpdateDataSuccess</td></tr><tr><td>Proud.CDbCacheClient2.RequestRemoveData</td><td>Proud.IDbCacheClientDelegate2.OnRemoveDataFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnRemoveDataSuccess</td></tr></tbody></table>

如果您想要blocked 調用， 而不是請求響應類型， 請使用這些方法 。

> * Proud.CDbCacheClient2.BlockedAddData
> * Proud.CDbCacheClient2.BlockedUpdateData
> * Proud.CDbCacheClient2.BlockedRemoveData

## 請求響應式 SessionGuid

獨佔Client各有一個Session,DB Cache Client爲了區分各Session,使用Guid值。\
請求時，通過Output參數獲取SessionGuid值，並獲取響應<mark style="color:orange;">Event的 CCallbackArgs::m\_sessionGuid</mark>獲取值。 保存<mark style="color:orange;">outSessionGuid</mark>後進行比較，可以確認請求的session。

**請求**

```
CDbCacheClient2::RequestExclusiveLoadNewData(String rootTableName, CPropNodePtr addData, Guid &outSessionGuid);
```

**回應**

```
IDbCacheClientDelegate2::OnExclusiveLoadDataFailed(CCallbackArgs args)
```

{% hint style="info" %}
**請求**中的 <mark style="color:orange;">outSessionGuid</mark> 等於**回應**中的 <mark style="color:orange;">args.m\_sessionGuid</mark>。
{% endhint %}

## 存取非專有數據方法

<mark style="color:orange;">Proud.CDbCacheServer2StartParameter.m\_allowNonExclusiveAccess</mark> 必須設定為允許非獨佔存取。

<table data-full-width="false"><thead><tr><th width="397">呼叫方法</th><th>結果回撥</th></tr></thead><tbody><tr><td>Proud.CDbCacheClient2.RequestNonExclusiveSnapshotData</td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveSnapshotDataFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveSnapshotDataSuccess</td></tr><tr><td>Proud.CDbCacheClient2.RequestNonExclusiveAddData</td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveAddDataAck</td></tr><tr><td>Proud.CDbCacheClient2.RequestNonExclusiveRemoveData</td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveRemoveDataAck</td></tr><tr><td>Proud.CDbCacheClient2.RequestNonExclusiveSetValueIf</td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveSetValueIfFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveSetValueIfSuccess</td></tr><tr><td>Proud.CDbCacheClient2.RequestNonExclusiveModifyValue</td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveModifyValueFailed</td></tr><tr><td></td><td>Proud.IDbCacheClientDelegate2.OnNonExclusiveModifyValueSuccess</td></tr></tbody></table>

非壟斷性數據變更成功後，該數據變更將申報給曾壟斷加載的DB cache client。 爲了申報,以下方法將回電。

> * Proud.IDbCacheClientDelegate2.OnSomeoneAddData
> * Proud.IDbCacheClientDelegate2.OnSomeoneRemoveData
> * Proud.IDbCacheClientDelegate2.OnSomeoneModifyValue
> * Proud.IDbCacheClientDelegate2.OnSomeoneSetValue

爲了便於查看,將各請求和回應關係捆綁起來如下。

<mark style="color:orange;">Proud.CDbCacheClient2.RequestNonExclusiveSnapshotData</mark> : 獲取 Snapshot

```cpp
// 回應:
IDbCacheClientDelegate2::OnNonExclusiveSnapshotDataSuccess (CCallbackArgs args)
IDbCacheClientDelegate2::OnNonExclusiveSnapshotDataFailed (CCallbackArgs args)
```

<mark style="color:orange;">Proud.CDbCacheClient2.RequestNonExclusiveAddData</mark> : 添加數據

```cpp
// 回應:
IDbCacheClientDelegate2::OnNonExclusiveAddDataAck (CCallbackArgs args)
// 被壟斷的DB Cache Client的Callback Event:
IDbCacheClientDelegate2::OnSomeoneAddData(CCallbackArgs& args)
```

<mark style="color:orange;">Proud.CDbCacheClient2.RequestNonExclusiveRemoveData</mark> : 刪除數據

```cpp
// 回應:
IDbCacheClientDelegate2::OnNonExclusiveRemoveDataAck (CCallbackArgs args)
// 被壟斷的DB Cache Client的Callback Event:
IDbCacheClientDelegate2::OnSomeoneRemoveData (CCallbackArgs& args)
```

<mark style="color:orange;">Proud.CDbCacheClient2.RequestNonExclusiveModifyValue</mark> : 對數據進行特定的運算。(+, -, \*, /)

```cpp
// 回應:
IDbCacheClientDelegate2::OnNonExclusiveModifyValueSuccess (CCallbackArgs args)
IDbCacheClientDelegate2::OnNonExclusiveModifyValueFailed (CCallbackArgs args)
// 被壟斷的DB Cache Client的Callback Event:
IDbCacheClientDelegate2::OnSomeoneModifyValue (CCallbackArgs& args)
```

<mark style="color:orange;">Proud.CDbCacheClient2.RequestNonExclusiveSetValueIf</mark> : 請求比較並保存兩個值。

```cpp
// 回應:
IDbCacheClientDelegate2::OnNonExclusiveSetValueIfSuccess (CCallbackArgs args)
IDbCacheClientDelegate2::OnNonExclusiveSetValueIfFailed (CCallbackArgs args)
 
// 被壟斷的DB Cache Client的Callback Event:
IDbCacheClientDelegate2::OnSomeoneSetValue (CCallbackArgs& args)
```

## 使用DB cache時的注意事項

單方向型和請求響應型(獨家數據請求響應型\&Block型&非壟斷數據訪問)混用時的注意事項。

{% hint style="danger" %}

* 如果請求響應方法在使用期間使用單向方法，<mark style="color:orange;">Proud.IDbCacheClientDelegate2.OnAccessError</mark> 將被回饋。
* 在未收到對更改後的 Data 的響應的情況下使用單向方法可能會導致錯誤的數據進入 。
  {% endhint %}

***

## 活用

{% content-ref url="/pages/cPQ1Z5IlzKuwQISDnQuP" %}
[DB Cache 活用法](/proudnet.cn/proudnet/db_system/db_cache_ver2/using/usage.md)
{% endcontent-ref %}


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