Derby模式错误 [英] Derby Schema Error

问题描述

我要为我的桌面应用程序插入数据到Derby嵌入式数据库。但是Derby给我错误的模式未找到错误。
我试图通过创建模式为每个用户名解决错误，但不解决我的问题。我搜索互联网，但没有给定的解决方案解决了我的问题。

I am trying to insert data into Derby embedded database for my Desktop Application. But Derby is giving me error of Schema Not found error. I have tried to solve error by creating schema as per username, but does not solve my problem. I searched internet, but none of given solution solved my problem.

package derbyd.ui;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;


public class AddStudent extends javax.swing.JFrame {

private void bt_saveActionPerformed(java.awt.event.ActionEvent evt) {                                        
    String conURL = "jdbc:derby:myDB;create=true";
    String user = "SOURABH";
    String passwd = "pass";
    Connection con = null;
    Statement st = null;
    String query;
    ResultSet rs = null;
    try
    {
        Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
        con = DriverManager.getConnection(conURL, user, passwd);
        st = con.createStatement();
        System.out.println("Connection established");
        query = "INSERT INTO SOURABH.MyTable VALUES('"+txt_name.getText()+"','"+txt_surname.getText()+"')";
        st.executeUpdate(query);
        System.out.println("Added Successfully");
    }
    catch(Exception e)
    {
        System.out.println("Error ->"+e);
    }
}                                       


}

推荐答案

根据常见问题 Apache Derby，您将看到：

According to the Frequently Asked Questions of Apache Derby, you will see that:

模式只能由 CREATE SCHEMA 或在该模式中创建对象（表等）（这是隐式模式创建）。

A schema is only created by CREATE SCHEMA or creating an object (table etc.) in that schema (this is implicit schema creation).

Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
con = DriverManager.getConnection(conURL, user, passwd);
st = con.createStatement();
System.out.println("Connection established");

st.executeUpdate("CREATE TABLE MyTable" +
        "(name VARCHAR(255), surname varchar(255))");
System.out.println("Table created");

query = "INSERT INTO SOURABH.MyTable VALUES(" +
        "'" + txt_name.getText() + "','" + txt_surname.getText() + "')";
st.executeUpdate(query);
System.out.println("Added Successfully");

输出为：

Connection established
Table created
Added Successfully

如果您多次运行此语句，则会收到错误，因为表已经存在。要处理此问题，请此处。

If you run this statement more than once, you'll get an error because the table already exists. To deal with that, here.

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