Spring JDBC - multiple getJdbcTemplate().update(...) calls in same DAO func

Question

Hello there.
I am using pure spring jdbc to connect to a single mysql instance. My DAO class extends JdbcDaoSupport and I am inserting parent and child data into their respective tables by making two calls to getJdbcTemplate().update(...). However, an exception is raised upon call of the second (the child) insert, stating the parent table doesn't have a record with the child expects should be there. I run a query against the parent and child tables, and neither record is there..
I should also note that inserts do occur when i set autocommit to true in the datasource configuration. However, when I set autocommit to false, i get an exception, as described above.
Here are my questions:
1. How does getJdbcTemplate() work when managing a connection?
2. Does calling getJdbcTemplate() each of the two times means I'll get 2 separate (or unique) connections?
3. For question #2, I've also tried creating a local JdbcTemplate variable (let's call it myJdbcTemplate) that points to a single getJdbcTemplate() call. However, when calling myJdbcTemplate.update(...) for both the parent and then the child inserts, I get the same problem.
4. How can I resolve this issue? Must I use some sort of spring jdbc database transaction object?
Any responses or sample code would be appreciated.
Here's my current datasource configuration:
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${jdbc.driverClassName}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<property name="maxActive" value="100"/>
<property name="maxIdle" value="30"/>
<property name="maxWait" value="1000"/>
<property name="defaultAutoCommit" value="false"/>
<property name="removeAbandoned" value="true"/>
<property name="removeAbandonedTimeout" value="60"/>
<property name="validationQuery" value="Select sysdate() from dual"/>
</bean>
Edited by: MrVince on Oct 4, 2008 12:27 AM

Answer 1

duffymo wrote:
MrVince wrote:
Hello there.
I am using pure spring jdbc to connect to a single mysql instance. My DAO class extends JdbcDaoSupport and I am inserting parent and child data into their respective tables by making two calls to getJdbcTemplate().update(...). However, an exception is raised upon call of the second (the child) insert, stating the parent table doesn't have a record with the child expects should be there. I run a query against the parent and child tables, and neither record is there..\Not enough information to tell. Can you boil this down to a SSCE?I'm not clear on what you're asking for here. I did a quick google search for the term SSCE but am unclear about what you're talking about here. Can you provide a little more context to what you're asking for? If it takes too long or if it's going to bother you in responding, please disregard this part of my post. Are you asking for a DDL for those two specific tables?
>
Are you using a transaction manager? At the time I posted the question, no. See below for some detail.
Do you have a service that owns the transaction?At the time I posted the question, no. See at the bottom of the post for an update.
>
A parent/child relationship implies a foreign key relationship between the parent primary key and a child field. Does the parent primary key exist? Yes.
Is the child field allowed to be null? No.
How do you acquire the parent primary key to insert into the child field?From this variation of JdbcTemplate's update method:
int update(PreparedStatementCreator psc, KeyHolder generatedKeyHolder) Using logging, I can confirm a key is being returned. I use this key in the insert of the child. The key is of the expected value.
>
I should also note that inserts do occur when i set autocommit to true in the datasource configuration. However, when I set autocommit to false, i get an exception, as described above.Right, because the parent primary key hasn't been committed yet.
Are you using InnoDB tables? They're the only MySQL tables that enforce referential integrity.
Yes.
Here are my questions:
1. How does getJdbcTemplate() work when managing a connection?What does "work" mean?
You can get an idea by looking at Spring's source for the class. Your question isn't clear.I will rephrase. Will a new connection be retrieved (or attempted to be retrieved) each time getJdbcConnection() is called? Your response in the above quote snippet and the one below seem to address this, however.
>
2. Does calling getJdbcTemplate() each of the two times means I'll get 2 separate (or unique) connections?No, you'll get a reference to the connection that the template has. It doesn't acquire a new connection; it simply uses the connection that was injected into it.
As mentioned just above, this helps me understand. Thanks.
3. For question #2, I've also tried creating a local JdbcTemplate variable (let's call it myJdbcTemplate) that points to a single getJdbcTemplate() call. However, when calling myJdbcTemplate.update(...) for both the parent and then the child inserts, I get the same problem.
4. How can I resolve this issue? Must I use some sort of spring jdbc database transaction object? Of course this should be a single unit of work. You wouldn't want the parent insert to succeed and the children to fail. Exactly. I appreciate you words of understanding and your agreement on what should be done.
Update -- I made some changes since my original post.
Upon googling I found this: [http://sujitpal.blogspot.com/2007/03/spring-jdbctemplate-and-transactions.html]. I decided to use what seemed to be the less invasive declarative approach. I made the following changes to my code:
1. Updated my spring-ws-servlet.xml file to include a DataSourceTransactionManager.
<bean id="transactionManager"
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
          <property name="dataSource" ref="dataSource" />
</bean>2. In the same file, I also configure the TransactionProxyFactoryBean.
     <bean id="myDao"
          class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
          <property name="transactionManager" ref="transactionManager" />
          <property name="target" ref="testResultDao" />
          <property name="proxyTargetClass" value="true" />
          <property name="transactionAttributes">
               <props>
                    <prop key="save*">PROPAGATION_REQUIRED</prop>
                    <prop key="*">PROPAGATION_SUPPORTS,readOnly</prop>
               </props>
          </property>
     </bean>3. I then updated my maven pom.xml to include the following dependencies to support the additions I list above steps #1 and #2.
<dependency>
     <groupId>cglib</groupId>
     <artifactId>cglib-nodep</artifactId>
     <version>2.1_3</version>
</dependency>
<dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-aop</artifactId>
       <version>2.0-m4</version>
</dependency>Here are other portions that may provide some relevance.
The DAO implementation code.
public class TestResultDaoImpl extends JdbcDaoSupport implements TestResultDao {
     public Integer saveStartedTestResult(TestResult testResult) {          
          KeyHolder genKeyHolder = new GeneratedKeyHolder();
          Integer testResultId = null;
                // save parent record
          getJdbcTemplate().update(new SaveResultPac(testResult), genKeyHolder);
          testResultId = new Integer(genKeyHolder.getKey().intValue());
                // save child records
          StringBuilder sqlStmt = new StringBuilder("INSERT into Selected_Transaction " );
          sqlStmt.append("(trans_type_id, test_result_id, create_date, last_update_date) ");
          sqlStmt.append("values(?, ?, sysdate(), ?) ");
          getJdbcTemplate().batchUpdate(sqlStmt.toString(), new SaveSelectedTransactionListBpss(testResultId, testResult.getSelectedTransactionList()));
          return testResultId;
      // more code
}The declaration of the DAO bean, but I have a feeling this probably isn't relevant.
     <bean id="testResultDao" class="org.foobar.dao.impl.mysql.TestResultDaoImpl">
          <property name="dataSource" ref="dataSource"/>
    </bean>I inject testResultDao into there caller bean. Configuration is not listed here.
After following the above three steps, I was able to compile and deploy my code to my local test server. When I execute the code, I still get same Foreign Key violation error.
In light of your recommendations I think I'm going in the right direction. So what am I missing?
Edited by: MrVince on Oct 5, 2008 12:39 AM