Excel数据导入Mysql常见问题汇总：如何处理导入时遇到的外键约束问题？

import java.sql.*;

public class ImportData {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
            stmt = conn.createStatement();
            
            // 检查关联表是否存在对应的主键值
            String checkQuery = "SELECT id FROM parent_table WHERE id = '123'";
            ResultSet rs = stmt.executeQuery(checkQuery);
            if (!rs.next()) {
                System.out.println("关联表中不存在对应的主键值，插入失败！");
                return;
            }
            
            // 插入数据到子表
            String insertQuery = "INSERT INTO child_table (parent_id, value) VALUES ('123', 'abc')";
            int affectedRows = stmt.executeUpdate(insertQuery);
            if (affectedRows > 0) {
                System.out.println("数据插入成功！");
            } else {
                System.out.println("数据插入失败！");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

import java.sql.*;

public class ImportData {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
            stmt = conn.createStatement();
            
            // 检查关联表是否存在对应的主键值
            String checkQuery = "SELECT id FROM parent_table WHERE id = '123'";
            ResultSet rs = stmt.executeQuery(checkQuery);
            if (!rs.next()) {
                System.out.println("关联表中不存在对应的主键值，更新失败！");
                return;
            }
            
            // 更新带有外键约束的表中的数据
            String updateQuery = "UPDATE child_table SET value = 'xyz' WHERE parent_id = '123'";
            int affectedRows = stmt.executeUpdate(updateQuery);
            if (affectedRows > 0) {
                System.out.println("数据更新成功！");
            } else {
                System.out.println("数据更新失败！");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}