BATCH-1488: added reference doc section on the StoredProcedureItemWriter
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trisberg
@@ -1716,14 +1716,13 @@ staxItemWriter.write(trade);</programlisting>
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<section id="database">
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<title id="infrastructure.2.2">Database</title>
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<para>Like most enterprise application styles, a database is the
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central storage mechanism for batch. However, batch differs from
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other application styles due to the sheer size of the datasets
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with which the system must work. If a SQL statement returns 1
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million rows, the result set probably holds all returned results
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in memory until all rows have been read. Spring Batch provides two
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types of solutions for this problem: Cursor and Paging database
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ItemReaders.</para>
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<para>Like most enterprise application styles, a database is the central
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storage mechanism for batch. However, batch differs from other application
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styles due to the sheer size of the datasets with which the system must
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work. If a SQL statement returns 1 million rows, the result set probably
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holds all returned results in memory until all rows have been read. Spring
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Batch provides two types of solutions for this problem: Cursor and Paging
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database ItemReaders.</para>
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<section id="cursorBasedItemReaders">
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<title>Cursor Based ItemReaders</title>
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@@ -2039,6 +2038,127 @@ itemReader.close(executionContext);</programlisting>
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<property name="queryString" value="from CustomerCredit" />
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</bean></programlisting>
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</section>
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<section id="StoredProcedureItemReader">
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<title>StoredProcedureItemReader</title>
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<para>Sometimes it is necessary to obtain the cursor data using a
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stored procedure. The <classname>StoredProcedureItemReader</classname>
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works like the <classname>JdbcCursorItemReader</classname> except that
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instead of executing a query to obtain a cursor we execute a stored
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procedure that returns a cursor. The stored procedure can return the
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cursor in three different ways:</para>
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<orderedlist>
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<listitem>
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<para>as a returned ResultSet (used by SQL Server, Sybase, DB2,
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Derby and MySQL)</para>
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</listitem>
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<listitem>
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<para>as a ref-cursor returned as an out parameter (used by Oracle
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and PostgreSQL)</para>
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</listitem>
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<listitem>
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<para>as the return value of a stored function call</para>
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</listitem>
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</orderedlist>
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<para>Below is a basic example configuration using the same 'customer
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credit' example as earlier:</para>
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<programlisting><bean id="reader" class="org.springframework.batch.item.database.StoredProcedureItemReader">
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<property name="dataSource" ref="dataSource"/>
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<property name="procedureName" value="sp_customer_credit"/>
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<property name="rowMapper">
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<bean class="org.springframework.batch.sample.domain.CustomerCreditRowMapper"/>
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</property>
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</bean>
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</programlisting>
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<para>This example relies on the stored procedure to provide a
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ResultSet as a returned result (option 1 above). </para>
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<para>If the stored procedure returned a ref-cursor (option 2) then we
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would need to provide the position of the out parameter that is the
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returned ref-cursor. Here is an example where the first parameter is
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the returned ref-cursor:</para>
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<programlisting><bean id="reader" class="org.springframework.batch.item.database.StoredProcedureItemReader">
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<property name="dataSource" ref="dataSource"/>
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<property name="procedureName" value="sp_customer_credit"/>
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<property name="refCursorPosition" value="1"/>
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<property name="rowMapper">
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<bean class="org.springframework.batch.sample.domain.CustomerCreditRowMapper"/>
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</property>
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</bean>
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</programlisting>
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<para>If the cursor was returned from a stored function (option 3) we
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would need to set the property "<varname>function</varname>" to
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<literal>true</literal>. It defaults to <literal>false</literal>. Here
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is what that would look like:</para>
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<programlisting><bean id="reader" class="org.springframework.batch.item.database.StoredProcedureItemReader">
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<property name="dataSource" ref="dataSource"/>
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<property name="procedureName" value="sp_customer_credit"/>
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<property name="function" value="true"/>
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<property name="rowMapper">
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<bean class="org.springframework.batch.sample.domain.CustomerCreditRowMapper"/>
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</property>
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</bean>
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</programlisting>
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<para>In all of these cases we need to define a
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<classname>RowMapper</classname> as well as a
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<classname>DataSource</classname> and the actual procedure
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name.</para>
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<para>If the stored procedure or function takes in parameter then they
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must be declared and set via the parameters property. Here is an
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example for Oracle that declares three parameters. The first one is
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the out parameter that returns the ref-cursor, the second and third
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are in parameters that takes a value of type INTEGER:</para>
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<programlisting><bean id="reader" class="org.springframework.batch.item.database.StoredProcedureItemReader">
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<property name="dataSource" ref="dataSource"/>
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<property name="procedureName" value="spring.cursor_func"/>
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<property name="parameters">
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<list>
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<bean class="org.springframework.jdbc.core.SqlOutParameter">
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<constructor-arg index="0" value="newid"/>
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<constructor-arg index="1">
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<util:constant static-field="oracle.jdbc.OracleTypes.CURSOR"/>
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</constructor-arg>
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</bean>
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<bean class="org.springframework.jdbc.core.SqlParameter">
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<constructor-arg index="0" value="amount"/>
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<constructor-arg index="1">
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<util:constant static-field="java.sql.Types.INTEGER"/>
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</constructor-arg>
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</bean>
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<bean class="org.springframework.jdbc.core.SqlParameter">
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<constructor-arg index="0" value="custid"/>
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<constructor-arg index="1">
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<util:constant static-field="java.sql.Types.INTEGER"/>
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</constructor-arg>
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</bean>
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</list>
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</property>
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<property name="refCursorPosition" value="1"/>
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<property name="rowMapper" ref="rowMapper"/>
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<property name="preparedStatementSetter" ref="parameterSetter"/>
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</bean></programlisting>
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<para>In addition to the parameter declarations we need to specify a
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<classname>PreparedStatementSetter</classname> implementation that
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sets the parameter values for the call. This works the same as for the
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<classname>JdbcCursorItemReader</classname> above. All the additional
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properties listed in <xref linkend="JdbcCursorItemReaderProperties" />
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apply to the <classname>StoredProcedureItemReader</classname> as well.
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</para>
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</section>
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</section>
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<section id="pagingItemReaders">
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