jdbcÁ¬½Ósql server
import java.sql.*;
public class JdbcUtil
{
public static void close(Statement st, Connection con)
{
try
{
st.close();
}catch(Exception e)
{
}
try
{
con.close();
}catch(Exception e)
{
}
}
public static void close(ResultSet rs, Statement st, Connection con)
{
try
{
rs.close();
}catch(Exception e)
{
}
close(st, con);
}
public static Connection getConnection() throws Exception
{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
return DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db", "sa", "54321");
}
}
Ïà¹ØÎĵµ£º
1.Oracleɾ³ýÖظ´¼Ç¼.
ɾ³ý±íÖжàÓàµÄÖظ´¼Ç¼£¬Öظ´¼Ç¼ÊǸù¾Ýµ¥¸ö×ֶΣ¨peopleId£©À´Åжϣ¬Ö»ÁôÓÐrowid×îСµÄ¼Ç¼.
delete from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
and rowid not i ......
²éѯÖظ´Öµ£¬ÏÔʾ³ö²»Öظ´µÄ²¿·Ö
select distinct(employeeid) from orders
²éѯÁ½¸ö±íÖ®¼äÏàͬÊý¾Ý
select orders.EmployeeID,Employees.EmployeeID
from orders INNER JOIN Employees
on Employees.EmployeeID=orders.EmployeeID
ʵÏÖÄ¿µÄ£¬Ò»¸ö±í´æ·ÅÓû§±àºÅºÍÓû§Ãû£¬ÔÚÁíÒ»¸ö±íÖпÉÒÔ¸ù¾ÝÓû§±àº ......
Ò²ÊÇSQL Server 2005´øÀ´µÄÐÂÌØÐÔ£¬²¿·Ö±¸·Ý£¨partial backup£©×Ô¶¯´´½¨Êý¾Ý¿âÖÐÖ÷Îļþ×éºÍËùÓ줻î¶Áд¹¦ÄܵÄÎļþ×éµÄ±¸·Ý¡£Èç¹û±¸·Ý´æÔÚÖ»¶ÁÎļþ×éµÄÊý¾Ý¿â£¬²¿·Ö±¸·Ý½«Ö»¶ÔÖ÷Îļþ×é½øÐб¸·Ý¡£Õâ¸öÑ¡Ïî¶ÔÓÚÄÇЩ´æÔÚÖ»¶ÁÎļþ×éµÄ³¬´óÐÍÊý¾Ý¿âÊÇÀíÏëµÄ£¬Ëü²»ÐèÒªÏñÄÇЩ¿ÉдµÄÎļþ×鱸·ÝµÃÄÇôƵ·±¡£
³ýÁËÐèÒªÖ¸¶¨READ_WRIT ......
ORACLE SQLÐÔÄÜÓÅ»¯
ORACLE SQLÐÔÄÜÓÅ»¯ÏµÁÐ (Ò»)
1. Ñ¡ÓÃÊʺϵÄORACLEÓÅ»¯Æ÷
ORACLEµÄÓÅ»¯Æ÷¹²ÓÐ3ÖÖ:
a. RULE (»ùÓÚ¹æÔò) b. COST (»ùÓڳɱ¾) c. CHOOSE (Ñ¡ÔñÐÔ)
ÉèÖÃȱʡµÄÓÅ»¯Æ÷,¿ÉÒÔͨ¹ý¶Ôinit.oraÎļþÖÐOPTIMIZER_MODE²ÎÊýµÄ¸÷ÖÖÉùÃ÷,ÈçRULE,COST,CHOOSE,ALL_ROWS,FIRST_ROWS . Ä㵱ȻҲÔÚSQ ......