私のコードは select ステートメントを問題なく実行できますが、何らかの理由で挿入セグメントと削除セグメントを機能させることができません。私はそれらが同じであるべきだと信じていますよね？ここのコードの何が問題なのかわかりません。
else if (e.getSource() == executeButton) {
//Create a statement
if (enterSQLText.getText().toLowerCase().contains("select")){
try{
String commandString = enterSQLText.getText();
Statement statement = conn.createStatement();
//Execute a statement
ResultSet resultSet = statement.executeQuery(commandString);
//Process query results
ResultSetMetaData metaData = resultSet.getMetaData();
int numberOfColumns = metaData.getColumnCount();
for(int i = 1; i<= numberOfColumns; i++){
executionResultText.append(metaData.getColumnName(i) + "\t");
System.out.printf("%20s\t", metaData.getColumnName(i));
}
executionResultText.append("\n");
System.out.println();
while (resultSet.next()){
for (int i = 1; i <= numberOfColumns; i++){
executionResultText.append(resultSet.getObject(i).toString() + "\t");
System.out.printf("%20s\t", resultSet.getObject(i));
}
executionResultText.append("\n");
System.out.println();
}
System.out.println("Execute Button Works!");
}
catch (Exception h){
h.printStackTrace();
}
}
else if (enterSQLText.getText().toLowerCase().contains("delete") || enterSQLText.getText().toLowerCase().contains("insert")) {
try {
String commandString = enterSQLText.getText();
Statement statement = conn.prepareStatement(commandString);
ResultSet resultSet = statement.executeUpdate(commandString);
}
catch (Exception l){
l.printStackTrace();
}
}
else {
executionResultText.setText("Sorry, that is not a valid command");
System.out.println("Not a vilid command.");
}
}
else if ステートメント内で問題が発生しています。通常、insert または delete ステートメントを実行しようとすると、スタック トレース エラーがスローされます。誰か助けてくれませんか？
編集：
コードを実行するには、else if セグメントを次のように変更する必要がありました。
else if (enterSQLText.getText().toLowerCase().contains("delete") || enterSQLText.getText().toLowerCase().contains("insert")) {
try {
String commandString = enterSQLText.getText();
Statement statement = conn.prepareStatement(commandString);
@SuppressWarnings("unused")
int resultSet = statement.executeUpdate(commandString);
}
catch (Exception l){
l.printStackTrace();
}
}
挿入または削除コマンドを実行しようとすると、次のようなスタック トレースが表示されます。
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'Mark Renshaw' for key 'PRIMARY'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1040)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2728)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1811)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1725)
at ConnectToDB.actionPerformed(ConnectToDB.java:203)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
そのセグメントに対して何をしても、データベースに接続できなくなるか、エラーがスローされます。