Question

我需要创建一个动态查询来更新行，并为用户提供该行中存在的每个列的输入窗口，然后在查询中插入这些值。

我现在不知道该怎么做，因为我是编程新手。

这是我的代码：

try {
  Class.forName("org.sqlite.JDBC");
  c = DriverManager.getConnection("jdbc:sqlite:test.db");
  c.setAutoCommit(true);
  System.out.println("Opened database successfully");
  stmt = c.createStatement();
  ResultSet rs = stmt.executeQuery("SELECT * FROM "+tablename);
  ResultSetMetaData rsmd = rs.getMetaData();
  //Grabs the first,second and third column name which only is used if you are deleting   from the SPJ table.
  FirstColumn = rsmd.getColumnName(1);
  SecondColumn = rsmd.getColumnName(2);
  ThirdColumn = rsmd.getColumnName(3);
  //Changes the query depending on what table you have chosen
  if(tablename.equals("SPJ")) {
    query = "UPDATE "+ tablename +" WHERE " + FirstColumn + " = '" + row1 + "' AND " +  SecondColumn + " = '" + row2 + "' AND " + ThirdColumn + " = '" +row3+"'" ;

} else {
        query = "UPDATE "+ tablename +" WHERE " + FirstColumn + " = '" + row + "'  VALUES("+values+")";
  }
int columnCount = rsmd.getColumnCount();
  Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; ++i) {
row[i - 1] = rs.getString(i); // Or even rs.getObject()
}
// runs the query.
  stmt.executeUpdate(query);
//closes connections
  stmt.close();
  c.close();

我尝试了这个，它为每个列提供了一个输入面板并将其放入数组但是我在WHERE附近遇到了sql语法错误？：/

int columnCount = rsmd.getColumnCount();
  Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; ++i) {
row[i-1] = JOptionPane.showInputDialog("Insert value: "+i); // Or even rs.getObject()
System.out.println(Arrays.toString(row));

}
}

Answer 1

您使用错误的UPDATE语法。你应该使用这样的东西：

UPDATE table_name SET column1 = value1，column2 = value2，... WHERE some_column = SOME_VALUE;

有关更新的更多示例，请参阅此链接：SQL UPDATE

我错过了UPDATE语句中的SET。 VALUES用于INSERT语句。

动态更新查询

1 个答案: