1.JDBC连接ORACLE
//1.加载驱动 Class.forName("oracle.jdbc.driver.OracleDriver"); //2.得到连接 Connection conn = DriverManager. getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl","scott","tiger"); //3.创建statement对象 Statement sm = conn.createStatement(); //4.执行sql,并返回结果 ResultSet rs = sm.executeQuery("select * from emp"); while(rs.next()){ System.out.println("用户名是:"+rs.getString(2)); } //用完之后一定要关闭资源 rs.close(); sm.close(); conn.close();
2.JSP分页查询
<body> <h2>数据库分页示例</h2> <table border="1"> <tr><td>用户名</td><td>薪水</td></tr> <% //1.加载驱动 Class.forName("oracle.jdbc.driver.OracleDriver"); //2.得到连接 Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl","scott","tiger"); //3.创建statement对象 Statement sm = conn.createStatement(); //总页数 int pageCount = 0; //总记录数 int totalCount = 0; //单页容量 int pageSize = 3; //获取当前页数 String s_pageNow = request.getParameter("pageNow"); int pageNow = 1; if(s_pageNow!=null && !"".equals(s_pageNow)){ pageNow = Integer.valueOf(s_pageNow); } String sql = " select * from (select a1.*,rownum rn from " +"(select * from emp) a1 where rownum <="+pageNow*pageSize +") where rn>="+((pageNow-1)*pageSize+1); System.out.println(sql); String sql_total = " select count(*) from emp"; ResultSet rs = null; //4.执行sql,并返回结果 rs = sm.executeQuery(sql_total); if(rs.next()){ totalCount = rs.getInt(1); //计算页数 if(totalCount%pageSize==0){ pageCount = totalCount/pageSize; }else{ pageCount = totalCount/pageSize+1; } } rs = sm.executeQuery(sql); while(rs.next()){ out.println("<tr>"); out.println("<td>"+rs.getString(2)+"</td>"); out.println("<td>"+rs.getString(6)+"</td>"); out.println("</tr>"); } out.println("<tr>"); out.println("<td colspan='2'>"); for(int i=1;i<pageCount;i++){ out.println("<a href=fenye.jsp?pageNow="+i+"> "+i+"</a>"); } out.println("</td>"); out.println("</tr>"); //用完之后一定要关闭资源 rs.close(); sm.close(); conn.close(); %> </table> </body>
3. oracle小技巧
---------------------使用子查询插入数据 --新建要插入数据的表 create table kkk(myId number(4),myname varchar2(50),mydept number(5)); --通过子查询插入数据 insert into kkk (myid, myname, mydept) select empno, ename, deptno from emp where deptno = 10; ---------------------使用子查询更新数据 update emp set (job,sal,comm) = (select job, sal, comm from emp where empno = 7698) where empno = 7782;
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