java 之数据库

1，统计有多少记录

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class k1 { public static void mb_show(ResultSet r) { try { r.last(); System.out.println("数据表共有 "+r.getRow()+"行."); } catch (Exception e) { System.out.println("异常"+e.getMessage()); } } public static void main(String args[]) { try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection c=DriverManager.getConnection ("jdbc:odbc:studentDatabase"); Statement s=c.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE); ResultSet r=s.executeQuery("select * from 学生成绩"); mb_show(r); s.close(); c.close(); } catch (Exception e) { } } }

2，实现插入、删除、修改操作

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class c { public static void main(String args[]) { try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection c=DriverManager.getConnection ("jdbc:odbc:studentDatabase"); Statement s=c.createStatement(); // s.executeUpdate("ALTER TABLE 学生成绩 "+"add 性别 char(10)"); // s.executeUpdate("alter table 学生成绩 "+"drop column xingming"); s.executeUpdate("update 学生成绩 set chengji ='99' where xuehao='2' "); System.out.println("sdfs"); s.close(); c.close(); System.out.println("sdf"); } catch (Exception e) { System.out.println("yichang"+e.getMessage()); } } }