8.使用元数据分析数据库

package com.java1234.jdbc.chap08.sec01;

import java.sql.Connection;
import java.sql.DatabaseMetaData;

import com.java1234.jdbc.util.DbUtil;

public class Demo1 {

public static void main(String[] args)throws Exception {
DbUtil dbUtil=new DbUtil();
Connection con=dbUtil.getCon();
DatabaseMetaData dmd=con.getMetaData(); // 获取元数据
System.out.println("数据库名称："+dmd.getDatabaseProductName());
System.out.println("数据库版本："+dmd.getDriverMajorVersion()+"."+dmd.getDriverMinorVersion());

}
}

package com.java1234.jdbc.chap08.sec02;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;

import com.java1234.jdbc.util.DbUtil;

public class Demo2 {

public static void main(String[] args) throws Exception{
DbUtil dbUtil=new DbUtil();
Connection con=dbUtil.getCon();
String sql="select * from t_book";
PreparedStatement pstmt=con.prepareStatement(sql);
ResultSetMetaData rsmd=pstmt.getMetaData();
int num=rsmd.getColumnCount(); // 获取元数据列的总数
System.out.println("共有"+num+"列");
for(int i=1;i<=num;i++){
System.out.println(rsmd.getColumnName(i)+","+rsmd.getColumnTypeName(i));
}
}
}