oracle定义变量

------------------------------------定义使用变量----------------------------------

--scalar 变量
declare
v_ename varchar2(5);
v_sal number(6,2);
c_tax_rate constant number(3,2) :=0.03;
v_tax_sal number(6,2);
begin
select ename,sal into v_ename,v_sal from emp where empno=&eno;
v_tax_sal:=v_sal*c_tax_rate;
dbms_output.put_line('雇员名:'||v_ename);
dbms_output.put_line('雇员工资:'||v_sal);
dbms_output.put_line('所得税:'||v_tax_sal);
end;
/
--最好使用%type
declare
v_ename emp.ename%type;
v_sal emp.sal%type;
v_tax_rate constant number(3,2) :=0.03;
v_tax_sal v_sal%type;
begin
select ename,sal into v_ename ,v_sal from emp where empno=&no;
v_tax_sal := v_sal*v_tax_rate;
dbms_output.put_line('雇员名:'||v_ename);
dbms_output.put_line('雇员工资:'||v_sal);
dbms_output.put_line('所得税:'||v_tax_sal);
end;
/


--composite 变量
1：pl/sql记录
记录类型：emp_record_type
记录变量：emp_record
记录成员：记录变量.记录成员 emp_record.name
declare
type emp_record_type is record(
     name emp.ename%type,
     salary emp.sal%type,
     title emp.job%type);
emp_record emp_record_type;
begin
select ename,sal,job into emp_record from emp where empno=&no;
dbms_output.put_line('雇员名:'||emp_record.name);
dbms_output.put_line('雇员工资:'||emp_record.salary);
dbms_output.put_line(' 岗位:'||emp_record.title);
end;
/

2：pl/sql表
declare
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;
/

3:嵌套表
4：VARRAY

--Reference 变量
1：ref cursor 游标变量   fetch into
declare
type c1 is ref cursor;
dyn_cursor c1;
col1 varchar2(20);
col2 varchar2(20);
begin
open dyn_cursor for select &col1,&col2 from &tab where &con;
fetch dyn_cursor into col1,col2;
dbms_output.put_line('col1:'||col1);
dbms_output.put_line(' col2:'||col2);
close dyn_cursor;
end;

2:ref obj_type


--lob 变量
clob、blob、nclob、bfile
clob和nclob储存大字符数据
bolb储存大二进制数据
bfile储存指向os文件的指针

--使用子类型定义变量
subtype subtype_name is base_type [(constrain)] [not null];
declare
subtype my_type is varchar2(20);
v_name my_type(20);
begin
select ename into v_name from emp where empno=&no;
dbms_output.put_line('name：'||v_name);
end;
/

--非pl/sql变量
1：sql*plus变量
2：pro*c/c++变量