SQL如何用一条SQL语句更新表行

Question

我有一个包含 2 列的表，用于在 Oracle 数据库中存储应用程序设置。这是一个基本的例子：

我想创建一个 java 方法，用准备好的语句更新值。

示例代码：

更新代码

public void updateDBSettings() throws SQLException {


            String SQL_Statement = null;

            if (ds == null) throw new SQLException();      
       Connection conn = ds.getConnection();
            if (conn == null) throw new SQLException();      

       try {
            conn.setAutoCommit(false);
            boolean committed = false;
                try {
                       SQL_Statement = "UPDATE GLOBALSETTINGS SET (SettingName = ?, SettingValue = ?)";

                       PreparedStatement updateQuery = conn.prepareStatement(SQL_Statement);
                       updateQuery.setString(1, "20");
                       updateQuery.setString(2, "40");

                       updateQuery.executeQuery();

                       conn.commit();
                       committed = true;
                 } finally {
                       if (!committed) conn.rollback();
                       }
            }
                finally {               
                conn.close();

                }  

       }    

我知道这条 SQL 语句是错误的。写SQL语句的正确方法是什么？

最好的祝愿 彼得

P.S 更新代码后我得到这个错误堆栈：

javax.faces.el.E​​valuationException: java.sql.SQLSyntaxErrorException: ORA-00907: 缺少右括号

at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1542)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)

原因：java.sql.SQLSyntaxErrorException: ORA-00907: 缺少右括号

at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:445)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:879)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:450)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:192)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:207)
at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:1044)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1329)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3584)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3628)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:1493)
at com.sun.gjc.spi.jdbc40.PreparedStatementWrapper40.executeQuery(PreparedStatementWrapper40.java:642)
at com.DX_57.SM_57.Application.updateDBSettings(Application.java:124)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at javax.el.BeanELResolver.invokeMethod(BeanELResolver.java:779)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:528)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:257)
at com.sun.el.parser.AstValue.invoke(AstValue.java:248)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:302)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
... 32 more

Answer 1

正确的语法应该是这样的：

UPDATE GLOBALSETTINGS 
   SET settingValue = case 
                        when settingName = 'SessionTTL' = then ? 
                        when settingName = 'MaxUsersActive' = then ? 
                        else settingValue
                      end
WHERE settingName in ('SessionTTL', 'MaxUsersActive');

但我不建议这样做，因为它会使您的代码难以阅读和维护。

运行两个更新语句可能会更好：

String sql = 
   "UPDATE GLOBALSETTINGS " + 
   "  SET settingValue = ? " + 
   "WHERE settingName = ?";

PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "40");
pstmt.setString(2, "SessionTTL");
pstmt.executeUpdate();

pstmt.setString(1, "20");
pstmt.setString(2, "MaxUsersActive");
pstmt.executeUpdate();

如果您想保存一些到数据库的往返，您可以将其作为批处理语句运行：

pstmt.setString(1, "40");
pstmt.setString(2, "SessionTTL");
pstmt.addBatch();

pstmt.setString(1, "20");
pstmt.setString(2, "MaxUsersActive");
pstmt.addBatch();

pstmt.executeBatch();

这会将两个语句“一次性”发送到数据库服务器。

注意：我假设 settingName 是唯一的。

Answer 2

String sqlStatement =
    "update GLOBALSETTINGS " +
    "set SettingName = ?, " +
    "SettingValue = ?" +
    "where id = ?"; // You have to put where condition here, otherwise all rows will get affected. I assume your serch-key-column as id. Change 'id' according to your table
PreparedStatement updateQuery  = con.prepareStatement(sqlStatement);
updateQuery.setString(1, "20");
updateQuery.setString(2, "40");
updateQuery.setString(3, applicationSettingId);

您可以查看tutorials from oracle

Answer 3

SQL_Statement = "UPDATE GLOBALSETTINGS SET (SettingName = ?, SettingValue = ?)";