java 之数据库

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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());}}}