列索引无效,使用PreparedStatement进行更新

Question

我正在使用PreparedStatement更新表

以下代码完美运行

pst = conn.prepareStatement("UPDATE playjdbc SET jlname ='javafx10new' WHERE jfname = 'java10'");
int i = pst.executeUpdate();

但是当我尝试这样的时候它会抛出异常

 pst = conn.prepareStatement("UPDATE playjdbc SET jlname ='javafx10new' WHERE jfname =?");
 pst.setString(2, "java10"); // yeah second column is jfname

 int i = pst.executeUpdate();

堆栈跟踪 :

java.sql.SQLException: Invalid column index
    at oracle.jdbc.driver.OraclePreparedStatement.setStringInternal(OraclePreparedStatement.java:5330)
    at oracle.jdbc.driver.OraclePreparedStatement.setString(OraclePreparedStatement.java:5318)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.setString(OraclePreparedStatementWrapper.java:282)
    at com.indus.database.EmployeeDTO.updateData(EmployeeDTO.java:114)

Answer 1

以下2是指查询字符串中问号的位置,而不是数据库表中列的位置,而不是查询中使用的列名的顺序:

 pst.setString(2, "java10"); // yeah second column is jfname

请改用1.

pst.setString(1, "java10"); // first question mark is jfname