Oracle学习之路

 SELECT TO_DATE('12-3月-04') FROM dual;
 select * from dept for update;
 
 update dept t set t.dept_time=to_date('2013-01-13','yyyy-mm-dd') where t.deptno='10';
 
 
 
 SELECT *  FROM NLS_DATABASE_PARAMETERS
 
 select * from nls_session_parameter；ggggggggggggggggggggggggggggggggggggggggggg
 
 --有空值 count(列) count(*)不一样
 select count(t.dname) from dept t ;
 select count(*) from dept;
 
 
 select * from dept;
 
 --查询当前用户信息
 select user from dual;
 
 connect tt/tt11;
 
 
 
 SELECT *  FROM NLS_DATABASE_PARAMETERS;
 
 
 select * from emp for update;
 
 --分组统计男女
 select sum(decode(sex,'男',1,0)) 男人数,sum(decode(sex,'女',1,0)) 女人数 from emp;
 
 select * from abc;
 
 --nvl系统函数处理空值
  select deptno, nvl(dname,'未输入')from dept;
 
  select * from dept t where t.dname is null;
 
  select * from dept t where t.dname=null;--判断为空错误写法
 
  select * from dept t order by t.deptno asc;
  select * from dept t order by t.deptno desc;
    select * from dept t for update;
   
    select distinct loc from dept;
   
   
 
 
  select empno, ename, job, mgr, hiredate, sal, comm, deptno, sex from emp;
 
  select (t.deptno*sal) from emp t;
  --分组查询
  select  sex ,count(sex) from emp group by sex having count(sex)>1;
 
  --模糊查询 1981年雇佣的员工
  select * from emp t where t.hiredate like '1981%';--日期类型无法模糊
 
 
  --模糊查询销售员工
   select * from emp t where t.job like 'CLE%';
  
   --表的链接 部门和员工
   select * from emp e ;--for update;
   select * from dept d --for update;
  
   select e.empno 员工编号,d.deptno 部门编号 from emp e ,dept d
   where e.deptno = d.deptno;
  
   --内连接
     select e.empno 员工编号,e.sex 性别,d.dname 所在部门 from emp e join dept d
     on e.deptno = d.deptno;
    
     --外连接不完全匹配 --左连接
     select e.empno 员工编号,e.ename 姓名 ,e.sex 性别,d.dname 所在部门 from emp e join dept d
     on e.deptno = d.deptno(+);
    
      select e.empno 员工编号,e.ename 姓名 ,e.sex 性别,d.dname 所在部门 from emp e join dept d
     on e.deptno(+) = d.deptno;
  
  --子查询
  select * from emp e where e.deptno in (select d.deptno from dept d);
 
  select * from emp where exists (select e.empno from emp e where e.empno=22);
 
 select * from emp where exists (select * from dept where dept.deptno=emp.deptno);
 
 --union 使用
 select deptno  from emp union
 select deptno from dept;
 --intersect
 select deptno  from emp intersect
 select deptno from dept;
 
 --插入结果集
 insert into emp(empno,ename) select deptno,dname from dept;
 
 
 
 create table ttt as (select * from emp);
 
 select * from ttt;
 
 
 
 --视图

 1、Oracle8/8i/9i/10i数据库（thin模式）  

Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();  
String url="jdbc:oracle:thin:@localhost:1521:orcl"; //orcl为数据库的SID  
String user="test";  
String password="test";  
Connection conn= DriverManager.getConnection(url,user,password);  

　　 2、DB2数据库  

Class.forName("com.ibm.db2.jdbc.app.DB2Driver ").newInstance();  
String url="jdbc:db2://localhost:5000/sample"; //sample为你的数据库名  
String user="admin";  
String password="";  
Connection conn= DriverManager.getConnection(url,user,password);  

　　 3、Sql Server7.0/2000数据库  

Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();  
String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydb";  
//mydb为数据库  
String user="sa";  
String password="";  
Connection conn= DriverManager.getConnection(url,user,password);  

 
 

ibatis连接oracle异常：

java.sql.SQLException: Io 异常: NL Exception was generated 

 

    百度可能是连接url的问题：

    

 4、Sybase数据库  

Class.forName("com.sybase.jdbc.SybDriver").newInstance();  
String url =" jdbc:sybase:Tds:localhost:5007/myDB";//myDB为你的数据库名  
Properties sysProps = System.getProperties();  
SysProps.put("user","userid");  
SysProps.put("password","user_password");  
Connection conn= DriverManager.getConnection(url, SysProps);  

　　 5、Informix数据库  

Class.forName("com.informix.jdbc.IfxDriver").newInstance();  
String url = "jdbc:informix-sqli://123.45.67.89:1533/myDB:INFORMIXSERVER=myserver;  
user=testuser;password=testpassword"; //myDB为数据库名  
Connection conn= DriverManager.getConnection(url);  

　　 6、MySQL数据库  

Class.forName("org.gjt.mm.mysql.Driver").newInstance();  
String url ="jdbc:mysql://localhost/myDB?user=soft&password=soft1234&useUnicode=true&characterEncoding=8859_1"  
//myDB为数据库名  
Connection conn= DriverManager.getConnection(url);  

　　 7、PostgreSQL数据库  

Class.forName("org.postgresql.Driver").newInstance();  
String url ="jdbc:postgresql://localhost/myDB" //myDB为数据库名  
String user="myuser";  
String password="mypassword";  
Connection conn= DriverManager.getConnection(url,user,password);  

　　 8、access数据库直连用ODBC的 

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver") ; 
String url="jdbc:odbc:Driver={MicroSoft Access Driver (*.mdb)};DBQ="+application.getRealPath("/Data/ReportDemo.mdb"); 
Connection conn = DriverManager.getConnection(url,"",""); 
Statement stmtNew=conn.createStatement() ; 

    

    查看oracle连接的url

   

"jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=127.0.0.1)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=flight)(SERVER=DEDICATED))";

 

    复制到myeclipse java类文件中查看少了一个)晕，复制的问题：

     

jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=127.0.0.1)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=flight)(SERVER=DEDICATED)))