grant connect,create table to test1;
conn cyts_cc/cyts_cc@orcl2000;
create table(
id int)
tablespace user;
ERROR 位于W?1 ?
ORA-01950: 表空?USERS'中无权限
conn cyts_cc/cyts_cc@orcl2000;
alter user test1 quota 1M on users;
create tab
(id int);
success
alter user test1 account lock;
conn test1/test1@orcl2000;
ERROR:
ORA-28000: the account is locked
1 Database Schema
a schema is a named collection of objects
b user is created and a corresponding schema is created
c user can be associated only with one schema
d username and schema are often userd interchangely.
2 Checklist for creating users
a idntfigy tablespaces in which the usr nedds to store objects
b decide on quotas for each tablespace
c assign a default tablespace and temporary tablespace.if you do not specify at the time of create user,system tablespace will be the defalut tablespace and temporary.it will affect the performance of the oralce.
d create user
e grant privileges and roles to user
desc dba_users;
select * from dba_users;
3 Creating a new user:
Database Authentiacation
set the initial password
create user aaron
identified by soccer
default tablespace data
temporary tablespace temp
guota 15m on data
password expire;
alter database default temporary tablespace temp;
4 Creating a new user operating System Authentication
os_authent_prefix initialllization parameter specifies the format of the username
defauts to ops$
create user arron
identified externally
default tablespace users
temporary tablespace temp
quota 15m on data
password expire;
conn /
show parameter os
os_authent_prefix string OPS$
create user ops$test3
identified externally
default tablespace us
temporary tablespace
quota 10m on users
thee test2 is an user of os ,which the oracle is installed.
5 Changing user quota on tablespace
alter user test3 quota 4m on users;
you cann't grant quota on temp and undotbs.
alter quota 0 on uers -- means that no new table space can be allocated and cannot change the exist object in the tablespaces
6 drop user
you cannot drop user who has connected to oracle
drop user (cascade)
7 Obtaining User information
information about uers can be obtained by qerying the data dictionary
dba_users
名称
-----------------------------
USERNAME
USER_ID
PASSWORD
ACCOUNT_STATUS
LOCK_DATE
EXPIRY_DATE
DEFAULT_TABLESPACE
TEMPORARY_TABLESPACE
CREATED
PROFILE
INITIAL_RSRC_CONSUMER_GROUP
EXTERNAL_NAME
dba_ts_quotas
名称
---------------
TABLESPACE_NAME
USERNAME
BYTES
MAX_BYTES
BLOCKS
MAX_BLOCKS
]]>
The union operator returns results form both queries after eliminating duplications.\
select employee_id,job_id
from employees
uniion
select employ_id ,job_id
from job_history;
2 the all operator
The union all opertor reutrn result from both queries,including all duplications
3 interset
select ster_id,qty from sales where qty>20;
intersect
select ster_id,qty from sales where ster_id like '7%';
4 minus
select ster_id,qty from sales where qty>20
minus
select ster_id from sales where ster_id like '7%'
5 set operator guidelines
. teh expressions in the select list must match in number and data type;
. Parentheses can be used to alter the sequence of the execution
.The order by clause:
can appear only at the very end of the statement
will accept the column name,aliases from thee firest select statement ,or thee positional notation
.Duplicate row are atuomatically eliminated except in union all.
.Column names from the first query appear in the result
.The output is sorted in ascending order by default except in union all
6 matching the select statement
select department_id,to_number(null),location,hire_date
from employees
union
select department_id,location_id,to_date(null)
from departments;
select employee_id,job_id,salary
from employees
union
select employee_id,job_id,0
from job_history;
7 Controlling the order of the rows
select 'sing' as "my dream" ,3,a_dummy
from dual
union
select 'like''d like to teach',1
from dual
union
select 'the world to',2
from dual
order by 2;
]]>
is
begin
dbms_output.put_line(systimestamp);
end;
a 使用execute 命o调用q程
set serveroutput on
exec out_time;
b 使用call 命o调用q程
set serveroutput on
call out_time();
2) 建立q程Q带有in参数 默认入参敎ͼ另外也可以用in 关键子显C的定义
create or replace procedure add_employee
(eno number,name varchar2,sal number,
job varchar default 'clerk',dno number)
is
e_integrity exception;
pragma exception_init(e_intgegrity,-2291);
begin
insert into emp(empno,ename,sal,job.deptno)
values(eno.name,sal,job,dno);
exception
when dup_val_on_index then
raise_application_error(-20000,'雇员号不能重?);
when e_integrity then
raise_application_error(-20001,'部门号不存在');
调用
exec add_employee(111,'clark',200,'manager',10);
3 建立q程Q带有out 参数
create or replcace procedure query_employee
(eno number,name out varchar2,salary out number)
is
begin
select ename,sal,into name,salary from emp where empno=eno;
exception
when no_data_found then
raise_application_error(-20000,'G该雇员不存在');
end;
调用
var name varchar2(10)
var salary number
exec query_employee(7788,:name,:salary);
print name,salary;
4 建立q程Q带有in out 参数
create or replace procedure compute
(num1,in out number,num2 in out number)
is
v1 number;
v2 number;
begin
v1:=num1/num2;
v2:=mod(num1,num2);
num1:=v1;
num2:=v2;
end;
调用
var n1 number
var n2 number
exec :n1:=100;
exec :n2:=30
exec compute(:n1,:n2)
print n1 n2
5) 为参C递变量和数据 位置传递，名称传递，l合传?br /> create or replace procedure add_dept
(dno number,dname varchar2 default null,loc varchar default null)
is
begin
insert into dept values(dno.dname,loc);
end;
-- 位置传?br /> exec add_dept(50,'sales','new york');
exec add_dept(60);
exec add_dept(70,'admin');
-- 名称传?br /> exec add_dept(50,loc=>'new york');
exec add_dept(60,dname=>'sales',loc=>'new york');
6) 昄当前用户的所有程序及其源代码
select text from user_source where name='add_dept';
7) 删除q程
drop procedure add_dept;
2 开发函?br /> 可以在sql语句和其他子q程中执行?br /> 1 建立函数Q不带Q何参?br /> create or replace function get_user
return varchar2
is
v_user varchar2(100);
begin
select username into v_user from user_users;
return v_user;
end;
--使用变量接收函数q回?br /> var v2 varchar2(100)
exec :v1:=get_user
print v1;
-- 在sql 语句中直接调用函?br /> select get_user from dual;
-- 使用dbms_output 调用函数
set serveroutput on
exec dbms_output.put_line('get_user');
2) 建立函数Q带有in 参数
create or replace function get_sal(name in varchar2)
reutnr number
as
v_sal emp.sal%type;
begin
select sal into v_sal from emp where upper(ename)=upper(name);
return v_sal;
exception
when no_data_found then
raise_application_error(-20000,'employee does not exist');
end;
3) 建立函数Q带有out 参数
create or replace function get_info
(name varchar2,title out varchar2)
return varchar2
as
deptname dept.dname%type;
begin
select a,job,b,dname into title,deptname from emp a,dept b
where a.deptno=b.deptno
and upper(a.ename)=uppder(name);
return deptname;
end;
var job varchar2(20)
var dname varchar2(20)
exec :dname:=get_info('scott',job);
print dname job
4) 带有 in out 参数
create or replace function result
(num1,number,num2 in out nu8mber)
return number
as
v_result number(6);
v_remainder number;
begin
v_result:=num1/num2;
v_remainder:=mod(num1,num2);
num2:=v_remainder;
retrun v_result;
exception
when zero_divide then
raise_application_error(-20000,'zero divied');
end;
5) 函数调用的限?br /> -- 在sql 语句中只能调用存储函?br /> -- 在sql 语句中只能调用带有输入参数in Q而不能有输出参数out 和in out 参数的函?br /> -- 在sql 语句中调用的函数的参数必L标准的sql 数据cdQ不能是pl/sql 所Ҏ的数据类?br /> -- 在sql 语句中调用的函数不能包含insertQupdate 和delete
6) 查看源代?br /> set pagesize 40
select text form user_source where name='result';
7) 删除函数
drop function result;
3 理子程?br /> 1) 列出当前用户的子E序
select object_name,created,status form user_objects
where object_type in ('procedure','function');
2)列出子程序源代码
select text from user_sorce where name='raise_salary'
3)cd子程序编译错?br /> -- show errors
--使用数据字典user_errors 定错误原因和位|?br /> select line||'/'||position as "line/col",text error
from user_errors where name='raise_salary';
4) 列出对象的依赖关p?br /> -- 使用 user_dependenciess 定直接依赖关系
select name,type from user_dependencies
where referenced_name='emp'
-- 使用 deptree ?ideptree 定依赖和见解依赖关p?br /> select nested_level,name,type from deptree;
5) 重新~译子程?br /> 当被应用对象的结构被修改以后Q就会将相关依赖对象转变为无效invalid Q需要重新编?br /> 1
alter table emp add remark varchar2(100);
2
select object_name,object_type from user_objects
where status='invalid'
3
alter procedure add_employee compile;
alter view dept10 compile;
alter function get_info compile;
]]>
预定义分c，非预定义分类Q自定义例外?br />2 处理预定义例?br /> 1) 常用预定义例?br /> a access_into_null;
create type emp_type as object
(name varchar2(2),sal number(6,2));
declare
emp emp_type;
begin
emp.name:='scott';
exception
when access_into_null then
dbms_output.put_line('首先初始化对象emp');
b case_not_found
undef no
declare
v_val emp.sal%type;
begin
select sal into v_sal from emp where empno=&no;
case
when v_sal<1000 then
update emp set sal=sal+100 where empno=&no;
when v_sal<2000 then
update emp set sal=sal+150 where empno=&no;
when v_sal<3000 then
update emp set sal=sal+200 where empno=&no;
end case;
exception
when case_not_found then
dbms_output.put_line();
end;
c collection is null
在给集合元素Q嵌套表或arraycdQ赋值前Q必首先初始化集合元素
declare type ename_table_type is table of emp.eanme%type;
ename_table ename_table_type;
begin
select e_name into ename_talbe(2) from emp where empno=$no;
exception
when collection_is_null then
dbms_output.put_lilne('必须使用构造方法初始化集合元素');
end;
d currsor_already_open
reopen curosr 如果用户已经使用了open 命o打开了显C游标，或执行for循环(隐式的打开游标)
delcare
cursor emp_surosr is select ename,sal,from emp;
begin
open emp_curosr;
for emp_record in emp_cursor loop
dbms_output.put_line(emp_record.eanme);
end loop;
exception
when cursor_already_open then
dbms_output.put_line("游标已经打开");
end;
e dup_val_on_index
begin
exception
when dup_val_on_index then
dbms_output.put_line("列上不能出现重复?);
end;
d invalid_curosr
delcare
curosr emp_cursor is select ename,sla from emp;
emp_record emp_crusor%rowtype;
begin
fetch emp_cursor into emp_record;
close emp_crusro;
exception
dbms_output.put_line("游标没有打开");
end;
f invalid_number can not convert char to nmuber successfully
begin
update mep set sal=sal+1oo;
exception
when invalid_number then
g no_data_found when select into is executed ,no row is returned
declare
v_sal emp.sal%type;
begin
select sal into v_cal form emp where lower(ename)=lower('&name');
exception
when no_data_found then
dbms_output.put_line('没有q回l果');
end;
h too_many_row ora -01422 there are too many are return when "select into" is executed
i zero_divide ora-01476
g subscript_beyond_count ora-065533
declare
type emp_array_type is varray(20) of varchar2(10);
emp_array emp_array_type;
begin
emp_array:=emp_array_type('scott','mary');
dbms_output.put_line('emp_array(3)');
exception
when subscript_beyone_count then
dbms_out.put_line('出下标范围');
end;
k subscript_outside_limit
emp_array(-1);
l value_error the length of variable cannot contain the actual value;
declare
begin
end;
3 处理非预定义例外
delcare
e_integrity exception;
pragma exception_init(e_integrity,-2291);
begin
update emp set deptno=dno where empno=&no;
exception
when a_integrity then
end;
4 处理自定义例?br /> 与oracle 错误没有M联系Qؓ业务逻辑所定义的例?br /> delcare
e_no_employee exception;
begin
update emp set deptno=&dno where empno=&eno;
if sql%notfound then
raise e_no_employee;
end if;
exception
when e_no_emplyee then
dbms_output.put_line('该雇员不存在');
5 使用错误例外函数
使用例外函数可以取得错误号以及相关的错误消息Qsqlcode 用于取得oracle 的错误号Q而sqlerrm
则用于取得与之相关的错误信息?br /> 1 sqlcode ?sqlerrm
Z在pl/sql 应用E序中处理其他ؓ预料的到的oracle 错误Q用户可以在例外处理部分?br />when others 自句后，引用两个函数
declare
v_ename emp.ename%type;
begin
select ename into v_ename form emp where sal='&v_sal';
exception
when no_data_found then
when others then
dbms_output.put_line(sqlcode);
dbms_output.put_line(sqlerrm);
end;
2 raise_aaplicaition_error
只能在子E序中用（q程Q函敎ͼ包，触发器）
raise_application_error(error_number,message,[true|false]);
error_number 错误P在－20000刎ͼ20999 之间
message 指定错误消息Q不能超q?048
if v_comm is null then
raise_application_error(-20001,'该雇员无补助');
end if;
]]>
create or replace package emp_package is
g_deptno number(3):=30;
procedure add_employee(eno number,name varchar2,salary number dno number default g_deptno);
procedure fire_empoyee(eno number);
function get_sal(eno number) return number;
end emp_package;
2) 建立包体
用于实现包规范所定义的过E和函数。在包体中也可以单独定义U有lgQ包括变量，帔RQ过E和函数{。但在包体中所定义的组件只能在包内使用Q而不能由其他子程序引用?br /> create or replace package body emp_package is
function validate_deptno(v_deptno number)
return boolean;
is
v_temp int;
begin
select 1 into v_temp from dept where deptno=v_deptno;
return true;
exception
when no_data_found then
return false;
end;
procedure add_employee(eno number,name varchar2,salary number,dno number default g_deptno)
is
begin
if validate_deptno(dno) then
insert into emp(empno,ename,sal,deptno)
values(eno,name,salary,dno);
esle
raise_application_error(-20011,'部门不存?);
end if;
exception
when dup_val_on_index then
raise_application_error(-20011,'该雇员已存在')
end;
procedure fire_employee(eno number) is
begin
select from emp where empno=eno;
if sql%notfound then
raise application_error(-20012,'');
end if;
end;
function get_sal(eno number) return number
is
v_sal emp.sal%type;
begin
select sal into v_sal from emp where empno=eno;
return v_sal;
exception
when no_data_found then
raise_application_error(-200012,'');
end;
end emp_package;
3) 调用包组?br /> Q－ 在同一个包内调用组?不需要加包名前缀Q直接调?br /> create or replace paclage body emp_package is
procedure add_employee(eno number,name varchar2,salary number,dno number default g_deptno)
is
begin
validate_deptno(dno) then
exception
end;
-- 调用包公用变?br /> exec emp_package.g_deptno:=20
-- 调用公用q程
exec emp_package.add_employee(111,'mary,2000');
-- 调用q程数据库包的公用组?br /> exec emp_paclage.add_employee@orasrv(1116,'scott',1200);
4) 查看包源代码
select text from user_source where name='emp_package' and type='package';
5) 删除?br /> drop packagee emp_package;
2 使用包重?br /> 指多个具有相同名字的子程序，在调用的时候用不同的参数传递?br /> 1) 建立包规?br /> 同名q程和函数必d有不同的输入参数Q但同名函数q回值的cd数据必须相同
create or replace package overload is
function get_sal(eno number) return number;
function get_sal(name varchar2) return number;
procedure fire_employee(eno number);
procedure fire_employee(name varchar2);
2) 建立包体
。。?br />3) 使用包构造过E?br /> 初始化全局变量
1 建立包规?br /> create or replace packiage emp_package
is
minsal number(6,2);
maxsal number(6,2);
procedure upd_sal(eno number,salary number);
procedure upd_sal(name varhcar2,salary number);
end;-- 定义了两全局变量和三个公用过E?br /> 2 建立包体
create or replace package body emp_package is
procedure add_employee(cno number,name varchar2,salary number,dno number)
is
begin
if salary between minsal and maxsal then
insert into emp(empno,ename,sal,deptno)
........
-- 构造过E，位于子程序尾部，已begin 开始已end l束
begin
select min(sal),max(sal) into minsal,maxsal from emp;
end;
end;
3 调用包公用组?br /> 在同一ơ会话中W一ơ调用包的公用组建时Q会自动执行其它构造函敎ͼ而将来调用其他组建时则不会再调用其构造过E?br />4 使用U度U别
1 安包规?br /> create or replcace package purity is
minsal number(6,2);
maxsal number(6,2);
function max_sal return number;
function min_sal return number;
pragma restrict_references(max_sal,wnps);--wnps 不能修改包的变量Q不能给包的变量赋| --wnds 不能执行dml
pragma restrict_references(min_sal,wnps);--rnps 用于限制函数不能d包变?br /> end;
]]>
2) Constrains the deletion of a table if there are dependencies
2 Constrain Guidelines
1) Name a constraint or the oracle generate a name by the sys_cn format
2) Create a constraint either
--At the same time as the table is created.or
--After the table has been created
3)Define a constraint at the column or table level
4)view constraint in the data dictionary
3 Crete a constraint
create table test2
(id int not null,-- column level
lname varchar(20),
fname varchar(20),
constraint uk_test2_1 unique(lname,fname))--table level
4 The not null Constraint
create table employees(
employee_id number(6),
last_name varchar2(25) not null --system named
hire_date DATE
constraint emp_hire_date not null --User named
5Foreign key
create table test3
(rid int,
name varchar(30),
constraint fk_test3_1 foreign key(rid) reference test2(id));
froeign key constraint keywords
foreign key :Define the column in thee child table at the table constrain level.
references :Identifies the table and column in the parent table.
on delete cascade: Delete the dependent rows in the child table when a row in the parent table is deleted
on delete set null:Convert the dependent foreign key values to null when a row in the
parent table is deleted.
--parent table referenced table
--child table refernce other table
6 The check Constraint
Define a condition that each row must be satisfy
alter table test3
add constrain ch_test3 check(name like 's%')
7 Dropping a Constraint
1) Remove the manager constraint form the employee table
alter table test3
drop constriant test3_manager_fk
2) Remove the primary key constraint on the departments table and drop the associated
foreign key constraint on the employees.department_id column
alter table departments
drop primary key cascade
8 Disabling and enable Constraints
1)Execute the disable clause of the alter table statment to deactive an integrity constraint
2)Apply the cascade option to disable dependent integrity constrints
alter table employees
disable constraint emp_emp_id_pl cascade
3) enabling Constraints
.Active an integrity constraint currently disabled in the table definition by using the enable clause.
alter table employees
enable constraint emp_emp_id_pk;
a unique or a primary index is automatically created if you enable a unique key or a primary key constraint
8 View Constraints
select constraint_name,constriant_type,serch_condition
from user_constraints
where table_name='employees'
9 view the columns associated with constraints
select constraint_name,column_name
from user_cons_columns
where table_name='employees'
]]>
to make complex query easy
to provide data independence
to provide defferent view of the same data
2 Creating a View
1)create [or replace] [force|noforce] view view
as subquery
force : create view wether the referenced object existed or not
desc view_name;
2)create a view by using column aliases in the subquery
create view salv50
as select employee_idIO_NUMBER,last_name NAME,slaary*12 ANN_SALARY
from employees
where department_id=50;
3 Modigy a View
1) Modigy the emplvu80 view by using create or replace view clause.Add an alias for each column name;
create or replace view empvu80
(id_number,name,sal,department_id)
as select employee_id,first_name||" "||last_name,salary.department_id
from employees
where department_id=80;
column aliases in the create view clause are listed in the same order as the columns in the subquery
note : alter view_name is not a valid command.
4 Create a Complex View
Create a complex view that contains group functions to display values from two tables
create view dept_sum_vu
(name,minsal,maxsal,avgsal)
as
select d.department_name,min(e.salary),max(e.salary),avg(e.salary)
from employees e,departments d
where e.department_id=d.department_id
group by d.department_name;
5 Rules for performs DML operaton on a view
1) You can perform DML operation on simple views
2) You can not romove a row if the view contains the following:
--group functions
--a group by clause
--the distinct keyword
-- rownum keyword
-- column defined by expressions
6 Using the with check option Clause
1) you can ensure that dml operatons performed on the view stay within the domain of the view by using the with check option clause.
create view test1
as
select * from emp where qty>10;
with check option;
update testview1 set qty=10
where ster_id=6830;
--when you doing the following update operation
update testview1 set qty=5 where id=10;
-- an error will report
--you violate the where clause
2)Any attempt to change the department number for any row in the view fails because it violates the with check option constraint
create or replace view empvu20
as
select * where department_id=20
with check option constriant empvu20_ck;
7 Denying DML Operations
1 You can ensure that no dml operations occur by adding the with read only option to your view definition.
2)Any attempt to a DML on any row in the view resuls in an oralce server error.
8 remove veiw
drop view_name
9 inline view
1) an inline view is a subquery with an alias that you can use within a sql statement.
2) a named subquery in the from clause of the main query is an exqmple of an inline view
3) an inline view is not a schema object.
10 Top-N Analysis
1)Top_N querise ask for the n largest or smallest values of a column.
2)Both largest values and smallest values sets considered Top-N queries
select * from (select ster_id,qty from sales);
example
To display the top three earner names and salaries from the employees
select rownum as rank,last_name,salary
from (select last_anme,slary from employee
order by slary desc)
where rownum<=3;
]]>
type ename_table_type is table of emp.ename%type
index by binary_integer;
ename_table ename_table_type;
begin
select ename into ename_table(-1) from emp
where empno=&no;
dbms_output.put_line('雇员名：'||ename_table(-1));
end;
set serveroutput no
declare
type area_table_type is table of number
index by varchar2(10);
rea_table area_table_type;
begin
area_table('beijing'):=1;
area_table('shanghai'):=2;
area_table('guangzhou'):=3;
dbms_output.put_line(area_table.first);
dbms_output.put_line(area_table.last);
end;
2) 嵌套?br /> 索引表类型不能作为篏得数据类型用，但是嵌套表可以作cȝ数据cd使用?br />当用嵌套表元素Ӟ必须先用其构造方法初始化其嵌套表Q?br /> a 在pl/sql 块中使用嵌套?br /> declare
type ename_table_type is table of emp.ename%type;
ename_table ename_table_type;
begin
ename_table:=eanme_table_type('2','2','3');
select ename into ename table(2) from emp where empno=&no;
dbms_ouput.put_line(ename_table(2));
end;
b 在表中用嵌套表
create type phone_type is table of varchar2(20);
create table employee(
id number (4),name varchar2(10),sal number(6,2),
phone phone_type
)nested table phone store as phone_table;
-- 为嵌套表插入数据
insert into employee values(2,'scott',200,phone_type('2222','333333'));
Q－索嵌套表累得数据
set serveroutput on
declare
phone_table phone_type;
begin
select phone into phone_table
from employee where id=1;
for i in 1..phone_table.count loop
dbms_output.put_line(phone_table(i));
end loop;
end;
-- 更新嵌套表列的数?br /> delcare
phone_table phone_type:=('44444','555555');
begin
update employee set phone=phone_table
where id=1;
end;
3) 变长数组
在用varray 时必L定最大个敎ͼ和数据类?在用其元素时必进行初始化
type ename_table_type is varray(20) of emp.ename%type;
ename_table ename_table_type:=ename_table_type('1','2');
-- 在快中用varray
declare
type ename_table_type is varray(20) of emp.enameQtypeQ?br /> ename_table ename_table_type:=ename_table_type('mary');
begin
select ename into ename_table(1) form emp
where empno=&no;
end;
--在表列中使用varray
create type phone type is varray(20) of varchar2(20);
create table employee(
id number(4),name varchar2(10),
sal number(6,2),phone phone_type);
3)记录?br /> 记录表结合了记录和集合的优点
declare
type emp_table_type is table of emp%rowtype
index by binary_integer;
emp_table emp_table_type;
begin
select * from into emp_table(1) from emp
where empno=&no;
dbms_output.put_line(emp_table(1).ename);
end;
4)多维集合
1 多varray
declare
--define 一l集?br /> type al_array_type is varray(10) of int;
--定义二维集合
type nal_varray_type is varray(10) of a1_varray_type;
--初始化二l集?br /> nvl nal_varray_type:=nal_varray_type(
a1_varray_type(1,2),
a1_varray_type(2,3)
)
beign
for i in 1..nal_varray_type.count loop
for j in 1..a1_array_type.count loop
dbms_out.putline(nvl(i)(j));
end loop;
end loop;
end;
2 使用多嵌套?br /> table a1_table_type is table of int;
table nvl_table_type is table of a1_table_type;
nvl nvl_table_type:=nvl_table_type(
a1_table_type(1,2),
a1_table_type(2,3)
);
2 集合Ҏ
1) exist
if ename_table.exists(1) then
ename_table(1):='scott';
2) count q回当前集合变量中的元素M?br /> ename_table.count
3) limit q回集合元素的最大个敊W?只有varray ?br /> 4)first and last
ename_table.first
ename_table.last
5) prior 和next
ename_table.prior(5); Q－q回元素5的前一?br /> ename_table.next(5); -- 后一?br /> 6) extend
使用于varray ?嵌套表?br /> extend add a null value
extend (n) add n null value
extend (n,i)add n i value
declare
type ename_table_type is varray(20) of varchar2(20);
ename_table ename_table_type;
begin
ename_table:=ename_table_type('mary');
ename_table.extend(5,1);
dbms_output.put_line(ename_table.count);
end;
7) trim
trim remove one element from the tail of the collection.
trim(n) remove n element from the tail of the colleciton.
8)delete
delete: delete all the elements
delete(n) :delete the nth elements
delete(m,n): delete the elements from m to n
3 集合赋?br /> 1)一个集合的数据赋值给另一个集?clear the destination collectins and set the original collection
delcare
type name_varray_type is varray(4) of varchar2(10);
name_array1 name_varray_type;
name_array2 name_varray_type;
begin
name_array1:=name_varray_type('scott','smith');
name_array2:=name_array_type('a','b','c');
name_array1:=name_array2;
end;
type name_array1_type is varray(4) of varchar2(10);
type name_array2_type is varray(4) of varchar2(10);
name_array1 name_array1_type;
name_array2 name_array2_type;
h相同的数据类型，单具有不同的集合cd不能构赋?br /> 2) l集合赋城null ?br /> 可以使用delete ?trim
也可以?I集合赋l目表集?br /> type name_varray_type is varray(4) of varchar2(10);
name_array name_varray_type;
name_empty name_varray_type;
name_array:=name_varray_type('1','2');
name_array:=name_empty;
3) 使用集合操作赋和比较集合都是10g 的内容，p176 先略q?br />4 扚wl定
执行单词sql 操作能传递所有集合元素的数据?br /> 1 forall 语句
用于insert update 和delete操作。在oracle9i 中forall 语句必须hq箋的元?br /> 1) using forall on insert
declare
type id_table_type is table of number(6)
index by binary_integer;
type name_table_type is table of varchar2(2)
index by binary integer;
id_table id_table_type;
name_table name_table_type;
begin
for i in 1..10 loop
id_table(i):=i;
name_table(i):='Name'||to_char(i);
end loop;
forall i in 1..id_table.count
insert into demo values(id_table(i),name_table(i));
end;
2)using forall on using update
forall i in 1..id_table.count
upate demo set name:=name_table(i)
where id:=id_table(i);
3)using forall on using delete
forall i in 1..id_table.count
delete from demo where id:=id_table(i);
4) using forall on part of the collection
for i in1..10 loop
id_table(i):=i;
name_table(i):="name"||to_char(i);
end loop;
forall i in 8..10 l
insert into demo values(id_table(i),name_table(i));
2 bulk collect
is fit for select into ,fetch into and dml clause
1) using bulk collect
declares
type emp_table_type is table of emp%rowtype
index by binary_integer;
emp_table emp_table_type;
begin
select * bulk collect into emp_table
from emp where deptno=&no;
for i in 1..emp_tablee.count loop
dbms_output.put_line(emp_table(i).ename);
end loop;
2) 在dml 的返回字句用bulk collect 字句
declare
type ename_table_type is table of emp.ename%type;
ename_table ename_table_type;
begin
deletee from emp where deptno=&no
returning ename bulk_collect into ename_table;
for i in 1..ename_table.count loop
dbms_output.put(ename_table(i));
end loop;
end;
end;
end;
]]>
.the result of the subquery is used by the main query.
2 pairwise comarison subquery
select * from employee
where (manager_id,department_id) in
(select manager_id,department_id
from employees
where employee_id in (178,174))
and employee_id not in (178,174);
nonpairwise comparison subquery
select employee_id,manager_id,department_id
from employee
where manager_id in
(select manager_id
from employees
where employee id in (174,141))
and department_id in
(select department_id
from employees
where employee_id in (174,141))
and employ_id not in (174,141);
)
3 using a subquery in the from clause
select a.last_name,a,salary,b.slaavg
from employees a ,(select department_id,
avg(salary) salavg
from employees
group by department_id) b
where a.department_id=b.department_id
and a.salary>b.salavg;
4 scalar subquery expressions
. a scalar subquery expression is a subquery that return exactly on column value from one row
. in oracle8i scalar subqueries can be used in condition and expression part and all clause.
1) sclaar subqueries in casse expression
select employee_id ,last_name,
(case
when department_id=
(select department_id from departments
where location_id=1800)
then 'canada'
else 'usa'
end) location
from employees
2)scalar subqueries in order by clasue
select employee_id,last_name
from employees e
order by (select department_name
from departments d
where e.department_id=d.department);
4 correlated subqueries
the wubquery references a column form a table in the parment query
select column1,solumn2....
from table1 outer
where column1 operator
(select column1,column2
from table2
where expr1=out.expr2);
e.g 1
select last_name,salary,department_id
from employees outer
where salary>
(select avg(salary)
from employees
where department_id=
outer.department_id);
)
e.g 2
display details of those employees who have switched jobs at lease twice
select e.employee_id,last_name,e.job_id
from employees e
where 2<=(select count(*)
from job_history
where employee_id=e.employee_id);
6 using the exists operator
. the exists operator tests for existencee of rows in the results set of the subquery
. if a subquery row value id found:
the search does not continue in the inner query
the condition is flagged true
.if a subquery row value is not fount
the condition is flagged fasle
the search continues in the inner query
e.g
find employees who have at least one person reporting to them
select employee_id,last_name,job_id,department_id
from employees outer
where exists (select count(*)
from employees
where manager_id=outer.employee_id);
not exist.
7 corelated update
use a correlated subquery to update rows in on table based on rows from another table
e.g
--denormalize the employees table by adding a column to store the department name
alter table employees
add(department_name varchar2(14));
--populate the table by using a correlated update
update employees e
set department_name=
(select department_name
from departments d
where e.departmentid=d.department);
8 correlated delete
delete test1 t1
where ster_id in(select ster_id form sales t2 where t.ster_id=t2.ster_id);
9 using the with clause ,you can use the same query block in a a select statement when it cocurs more than once within a complex query
the with clause retrieves the results of a query block and stores it in the user's the user's templary tablespace
the with clause improves performance.
e.g
with
dept_costs as(
select d.department_name,sum(e.salary) as dept_total
from employee e,departments d
where e,department_id=d.department_id
group by d.department_name),
avg_cost as(
select sum(dept_total)/count(*) as dept_avg
from dept_cost)
select *
from dept_costs
where dept_total>(select dept_avg
from afb_cost)
order by department_name;
]]>