126 lines
8.2 KiB
HTML
126 lines
8.2 KiB
HTML
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<meta name="DC.Title" content="Change ResultSets" />
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<meta name="abstract" content="With the iSeries JDBC drivers, you can change ResultSets by performing several tasks." />
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<meta name="description" content="With the iSeries JDBC drivers, you can change ResultSets by performing several tasks." />
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<title>Change ResultSets</title>
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</head>
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<body id="rsltchng"><a name="rsltchng"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Change ResultSets</h1>
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<div><p>With the iSeries™ JDBC drivers, you can change ResultSets by
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performing several tasks.</p>
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<div class="section"><p>The default setting for ResultSets is read only. However, with Java™ Database
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Connectivity (JDBC) 2.0, the iSeries JDBC drivers provide complete support for
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updateable ResultSets.</p>
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<p>You can refer to ResultSet <a href="rsltchar.htm">concurrency</a> on
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how to update ResultSets.</p>
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<p><strong>Update rows</strong></p>
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<p>Rows may be updated
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in a database table through the ResultSet interface. The steps involved in
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this process are the following:</p>
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</div>
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<ol><li><span>Change the values for a specific row using various update<<em>Type</em>>
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methods, where <<em>Type</em>> is a Java data type. These update<<em>Type</em>>
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methods correspond to the get<<em>Type</em>> methods available for retrieving
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values.</span></li>
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<li><span>Apply the rows to the underlying database.</span></li>
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</ol>
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<div class="section"><p>The database itself is not updated until the second step. Updating
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columns in a ResultSet without calling the updateRow method does not make
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any changes to the database.</p>
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<p>Planned updates to a row can be thrown
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away with the cancelUpdates method. Once the updateRow method is called, changes
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to the database are final and cannot be undone.</p>
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<p><strong>Note:</strong> The rowUpdated
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method always returns false as the database does not have a way to point out
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which rows have been updated. Correspondingly, the updatesAreDetected method
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returns false.</p>
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<p><strong>Delete rows</strong></p>
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<p>Rows may be deleted in a database
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table through the ResultSet interface. The deleteRow method is provided and
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deletes the current row.</p>
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<p><strong>Insert rows</strong></p>
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<p>Rows may be inserted
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into a database table through the ResultSet interface. This process makes
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use of an "insert row" which applications specifically move the cursor to
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and build the values they want to insert into the database. The steps involved
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in this process are as follows:</p>
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<ol><li>Position the cursor on the insert row.</li>
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<li>Set each of the values for the columns in the new row.</li>
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<li>Insert the row into the database and optionally move the cursor back to
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the current row within the ResultSet.</li>
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</ol>
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<div class="note"><span class="notetitle">Note:</span> New rows are not inserted into the table where the cursor is positioned.
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They are typically added to the end of the table data space. A relational
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database is not position-dependent by default. For example, you should not
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expect to move the cursor to the third row and insert something that shows
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up before the forth row when subsequent users fetch the data.</div>
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<p><strong>Support
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for positioned updates</strong></p>
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<p>Besides the method for updating the database
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through a ResultSet, SQL statements can be used to issue positioned updates.
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This support relies on using named cursors. JDBC provides the setCursorName
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method from Statement and the getCursorName method from ResultSet to provide
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access to these values.</p>
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<p>Two DatabaseMetaData methods, supportsPositionedUpdated
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and supportsPositionedDelete, both return true as this feature is supported
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with the native JDBC driver.</p>
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<p>See <a href="usingpositionedupdate.htm">Example:
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Change values with a statement through another statement's cursor</a> for
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more information.</p>
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<p>See <a href="usingpositioneddelete.htm">Example:
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Remove values from a table through another statement's cursor</a> for more
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information. </p>
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</div>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="usingpositioneddelete.htm">Example: Remove values from a table through another statement's cursor</a></strong><br />
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This is an example of how to remove values from a table through another statement's cursor.</li>
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<li class="ulchildlink"><strong><a href="usingpositionedupdate.htm">Example: Change values with a statement through another statement's cursor</a></strong><br />
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This is an example of how to change values with a statement through another statement's cursor.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rsltsets.htm" title="The ResultSet interface provides access to the results generated by running queries. Conceptually, data of a ResultSet can be thought of as a table with a specific number of columns and a specific number of rows. By default, the table rows are retrieved in sequence. Within a row, column values can be accessed in any order.">ResultSets</a></div>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="rsltchar.htm" title="This topic discusses ResultSet characteristics such ResultSet types, concurrency, ability to close the ResultSet by committing the connection object, and specification of ResultSet characteristics.">ResultSet characteristics</a></div>
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<div><a href="rsltcurs.htm" title="The iSeries Java Database Connectivity (JDBC) drivers support scrollable ResultSets. With a scrollable ResultSet, you can process rows of data in any order using a number of cursor-positioning methods.">Cursor movement</a></div>
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<div><a href="rsltdata.htm" title="The ResultSet object provides several methods for obtaining column data for a row. All are of the form get<Type>, where <Type> is a Java data type. Some examples of these methods include getInt, getLong, getString, getTimestamp, and getBlob. Nearly all of these methods take a single parameter that is either the column index within the ResultSet or the column name.">Retrieve ResultSet data</a></div>
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<div><a href="rsltclse.htm" title="To create a ResultSet object, you can use executeQuery methods, or other methods. This article describes options for creating ResultSets.">Create ResultSets</a></div>
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</div>
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<div class="relref"><strong>Related reference</strong><br />
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<div><a href="resultex.htm" title="This is an example of how to use the ResultSet interface.">Example: ResultSet interface for IBM Developer Kit for Java</a></div>
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</div>
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</div>
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</body>
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</html>
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