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| − | {{EclipseLink_TLJPA
| + | #REDIRECT [[EclipseLink/UserGuide/JPA/2.4/toc]] |
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| − | |category=JPA
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| − | |release=2.4.x
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| − | |title=TLJPA }}
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| − | <span class="metaname"> </span>
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| − | {| class="simple oac_no_warn" width="100%"
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| − | {| class="simple oac_no_warn" width="100%"
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| − | [[Image:Elug_Magnifier.png|Search]][http://www.google.com/cse/home?cx=016171230611334810008:y5kxq4rqd8s&hl=en Search]
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| − | [[Image:Elug_guide_icon.png|Contents]][[EclipseLink/UserGuide/JPA/2.4/toc| Contents]]
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| − | |}
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| − | ----
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| − | {| width="165"
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| − | [[EclipseLink/UserGuide/JPA/2.4/a_array| Previous ]]<span class="previouslink">[[Image:Elug_previous_icon.png|Previous]]</span>
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| − | [[EclipseLink/UserGuide/JPA/2.4/a_cache| Next ]][[Image:Elug_next_icon.png|Next]]
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| − | [[Image:Elug_draft_icon.png|Warning]]Beta Draft: 2012-06-18
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| − | <span id="CHDCCIDA"></span>
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| − | ----
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| − | ==@BatchFetch==
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| − | Use <code>@BatchFetch</code> to read objects related to a relationship mapping (such as one-to-one, one-to-many, many-to-one, many-to-many, and element collection) to be read in a single query.
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| − | <span id="sthref25"></span>
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| − | ''' '''
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| − | ===Annotation Elements===
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| − | [[#CHDJBJBC|Table 2-3]] describes this annotation's elements.
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| − | <span id="sthref26"></span><span id="CHDJBJBC"></span>
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| − | '''''Table 2-3 @BatchFetch Annotation Elements'''''
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| − | {| class="HRuleFormalWide" dir="ltr" title="@BatchFetch Annotation Elements" summary="This table describes the list of attributes for this annotation." width="100%" border="1" frame="hsides" rules="rows" cellpadding="3" frame="hsides" rules="rows"
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| − | |- align="left" valign="top"
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| − | ! id="r1c1-t6" align="left" valign="bottom" | '''Annotation Element'''
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| − | ! id="r1c2-t6" align="left" valign="bottom" | '''Description'''
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| − | ! id="r1c3-t6" align="left" valign="bottom" | '''Default'''
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| − | |- align="left" valign="top"
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| − | | id="r2c1-t6" headers="r1c1-t6" align="left" |
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| − | size
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| − | | headers="r2c1-t6 r1c2-t6" align="left" |
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| − | Default size of the batch fetch, used only when <code>BatchFetchType</code>=<code>IN</code> to definite number of keys in each <code>IN</code> clause
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| − | | headers="r2c1-t6 r1c3-t6" align="left" |
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| − | <code>256</code> or the query's <code>pageSize</code> (for cursor queries)
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| − | |- align="left" valign="top"
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| − | | id="r3c1-t6" headers="r1c1-t6" align="left" |
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| − | BatchFetchType
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| − | | headers="r3c1-t6 r1c2-t6" align="left" |
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| − | (optional) The type of batch fetch to use:
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| − | * JOIN
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| − | * EXISTS
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| − | * IN
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| − | | headers="r3c1-t6 r1c3-t6" align="left" |
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| − | JOIN
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| − | |}
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| − | <br />
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| − | <span id="sthref27"></span>
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| − | ''' '''
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| − | ===Usage===
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| − | Batch fetching allows for the optimal loading of a tree. Setting the <code>@BatchFetch</code> annotation on a ''child'' relationship of a tree structure causes EclipseLink to use a ''single'' SQL statement for each level.
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| − | <span id="sthref28"></span>
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| − | ''' '''
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| − | ===Examples===
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| − | The following examples show how to use this annotation with different batch fetch types.
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| − | <span id="sthref29"></span>
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| − | '''''Example 2-7 Using JOIN BatchFetch Type'''''
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| − | <span id="sthref30"></span>
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| − | '''''Example 2-8 Using EXISTS BatchFetch Type'''''
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| − | <span id="sthref31"></span>
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| − | '''''Example 2-9 Using IN BatchFetch Type'''''
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| − | <span id="sthref32"></span>
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| − | ''' '''
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| − | ===See Also===
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| − | For more information, see:
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| − | * [[EclipseLink/UserGuide/JPA/2.4/a_joinfetch|"@JoinFetch"]]
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| − | <span id="footerspace"> </span>
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| − | ----
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| − | {| class="simple oac_no_warn" width="100%"
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| − | {| width="165"
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| − | | align="center" |
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| − | [[EclipseLink/UserGuide/JPA/2.4/a_array| Previous ]]<span class="previouslink">[[Image:Elug_previous_icon.png|Previous]]</span>
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| − | | align="center" |
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| − | [[EclipseLink/UserGuide/JPA/2.4/a_cache| Next ]][[Image:Elug_next_icon.png|Next]]
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| − | |}
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| − | | width="34%" align="center" |
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| − | [[Image:Eclipselink-logo.gif|150px|EclispeLink]]<br />[[Image:Elug_home_icon.png|EclipseLink logo]] [http://www.eclipse.org/eclipselink/ EclipseLink Home] • [[Image:Elug_pdf.png|PDF]] PDF (coming soon)<br />
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| − | {| class="simple oac_no_warn" width="225"
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| − | | align="center" valign="top" |
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| − | [[Image:Elug_Magnifier.png|Search]][http://www.google.com/cse/home?cx=016171230611334810008:y5kxq4rqd8s&hl=en Search]
| + | |
| − | | align="center" valign="top" |
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| − | [[Image:Elug_guide_icon.png|Contents]][[EclipseLink/UserGuide/JPA/2.4/toc| Contents]]
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| − | |}
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| − | |}
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