<rt id="bn8ez"></rt>
<label id="bn8ez"></label>

  • <span id="bn8ez"></span>

    <label id="bn8ez"><meter id="bn8ez"></meter></label>

    lqxue

    常用鏈接

    統計

    book

    tools

    最新評論

    hibernate version

    3.4.2 Version Attributes
    The Version field or property is used by the persistence provider to perform optimistic locking. It is
    accessed and/or set by the persistence provider in the course of performing lifecycle operations on the
    entity instance. An entity is automatically enabled for optimistic locking if it has a property or field
    mapped with a Version mapping.

    An entity may access the state of its version field or property or export a method for use by the application
    to access the version, but must not modify the version value[17]. Only the persistence provider is
    permitted to set or update the value of the version attribute in the object.

    The version attribute is updated by the persistence provider runtime when the object is written to the
    database. All non-relationship fields and properties and all relationships owned by the entity are
    included in version checks.

    The persistence provider's implementation of the merge operation must examine the version attribute
    when an entity is being merged and throw an OptimisticLockException if it is discovered that
    the object being merged is a stale copy of the entity—i.e. that the entity has been updated since the
    entity became detached. Depending on the implementation strategy used, it is possible that this exception
    may not be thrown until flush is called or commit time, whichever happens first.

    The persistence provider runtime is only required to use the version attribute when performing optimistic
    lock checking. Persistence provider implementations may provide additional mechanisms beside
    version attributes to enable optimistic lock checking. However, support for such mechanisms is not
    required of an implementation of this specification.[18]

    If only some entities contain version attributes, the persistence provider runtime is required to check
    those entities for which version attributes have been specified. The consistency of the object graph is not
    guaranteed, but the absence of version attributes on some of the entities will not stop operations from
    completing.

    posted on 2007-05-14 14:17 lqx 閱讀(298) 評論(0)  編輯  收藏


    只有注冊用戶登錄后才能發表評論。


    網站導航:
     
    主站蜘蛛池模板: 亚洲av色影在线| 免费一级国产生活片| 亚洲国产成人久久精品影视 | 日本人的色道www免费一区| 久久亚洲精品专区蓝色区| 7723日本高清完整版免费| 国产色在线|亚洲| 成**人免费一级毛片| 久久水蜜桃亚洲AV无码精品| 国产伦一区二区三区免费| 曰韩无码AV片免费播放不卡| 国内精品久久久久久久亚洲| 任你躁在线精品免费| 中文字幕亚洲色图| 搡女人真爽免费视频大全| 亚洲av无码专区亚洲av不卡| 亚洲成av人片一区二区三区| 成av免费大片黄在线观看 | 亚洲国产综合自在线另类| 精品久久久久国产免费| 亚洲第一se情网站| 亚洲熟妇无码乱子AV电影| 三年片在线观看免费| 久久精品国产亚洲AV久| 免费国产小视频在线观看| 中文字幕在线免费看线人| 亚洲精品中文字幕无乱码| 日韩一级免费视频| 精品国产免费一区二区三区香蕉 | av无码免费一区二区三区| 自拍偷自拍亚洲精品播放| 亚洲国产一二三精品无码| 一二三四影视在线看片免费 | 亚洲人成日本在线观看| 国产成人免费a在线视频app | 久操免费在线观看| 亚洲国产AV无码一区二区三区| 久久亚洲国产成人精品无码区| 亚欧色视频在线观看免费| 黄色网址大全免费| 亚洲成人免费网址|