From 200a40b332420f94992eb39a6d0ea1cf1490ffc4 Mon Sep 17 00:00:00 2001 From: coreyg Date: Fri, 21 Nov 2014 09:30:19 +0000 Subject: Adding tuscany's website to their svn repo for svnpubsub git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1640879 13f79535-47bb-0310-9956-ffa450edef68 --- site/trunk/site-publish/partialupdate.html | 124 +++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) create mode 100644 site/trunk/site-publish/partialupdate.html (limited to 'site/trunk/site-publish/partialupdate.html') diff --git a/site/trunk/site-publish/partialupdate.html b/site/trunk/site-publish/partialupdate.html new file mode 100644 index 0000000000..f124fc940a --- /dev/null +++ b/site/trunk/site-publish/partialupdate.html @@ -0,0 +1,124 @@ + + + + + + + + + + + + + + + Apache Tuscany : PartialUpdate + + + + + + + + + + + + + + + +
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+  Apache Tuscany > Home > DAS Overview > DAS Java > DAS Java Documentation Menu > DAS Java Developer Guide > RDB DAS Java > RDB DAS - User Guide > PartialUpdate + + User List | Dev List | Issue Tracker   +
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PartialUpdate

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The RDB DAS uses the SDO Change Summary to generate a set of database write operations. Rather than generated a statement to update all columns in a table that maps to a SDO DataObject Type, the DAS generates statements that update ony those columns that map to a modified DataObject property. For example, consider a Customer DataObject that has had the LastName property changed. The partial update statement generated by the DAS will look something like this:

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UPDATE CUSTOMER SET LASTNAME = ? WHERE ID = ?
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Rather than a statement that updates all columns like this:

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UPDATE CUSTOMER SET FIRSTNAME = ?, SET LASTNAME = ?, SET ADDRESS = ?, SET PHONE = ?, SET AGE = ?, SET SHOESIZE = ? WHERE ID = ?
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There are a couple of very good reasons for using a partial update approach. For one, a performance boost can be realized by applications writing to wide tables. For example, tables with over 100 columns are not unheard of. It can be a huge waste of resource to update 100 columns when only one was modified. Another reason for partial update is that some databases employ triggerson specific columns in a table. Partial updates are necessary when column triggers are employed to avoid tripping the trigger on every row update rather than only on updates to the specific column.

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