講稿控制結(jié)構(gòu)與語句

控制結(jié)構(gòu)與語句Episode

III,

Part

IIIEpisode

III控制結(jié)構(gòu)與語句結(jié)構(gòu)目標(biāo)預(yù)備知識回顧內(nèi)容總結(jié)作業(yè)目標(biāo)掌握在PL/SQL塊中可用的基本語法單元函數(shù)注釋嵌套塊熟練在PL/SQL塊中執(zhí)行SQL語句熟練使用IF，CASE，循環(huán)結(jié)構(gòu)預(yù)備知識回顧內(nèi)容基本語法單元PL/SQL中的SQL語句控制結(jié)構(gòu)內(nèi)容基本語法單元PL/SQL中的SQL語句控制結(jié)構(gòu)注釋單行注釋

--多行注釋

/*

*/可用的函數(shù)全部單行函數(shù)不可用的函數(shù)分組函數(shù)DECODE函數(shù)全部轉(zhuǎn)換函數(shù)嵌套塊DECLAREv_outer_variable

VARCHAR2(20):='GLOBAL

VARIABLE';BEGINDECLAREv_inner_variable

VARCHAR2(20):='LOCAL';BEGINDBMS_OUTPUT.PUT_LINE(v_inner_variable);DBMS_OUTPUT.PUT_LINE(v_outer_variable);END;DBMS_OUTPUT.PUT_LINE(v_outer_variable);END;BEGIN

<<outer>>DECLAREv_salmNUMBER(7,2)

:=

60000;NUMBER(7,2):=v_sal*0.20;VARCHAR2(255)

:=

'

eligible

for

commission';v_messageBEGINDECLAREv_salmNUMBER(7,2)NUMBER(7,2):=:=50000;0;pNUMBER(7,2):=v_sal+m;BEGINv_message

:=

'CLERK

not'||v_message;m

:=

v_sal

*

0.30;END;v_message

:=

'SALESMAN'||v_message;END;ENDouter;/內(nèi)容基本語法單元PL/SQL中的SQL語句控制結(jié)構(gòu)SELECT…INTO只適用于查詢結(jié)果為一行SELECTINTOFROM[WHEREselect_list{variable_name[,

variable_name]...|

record_name}tablecondition];DECLAREv_fname

VARCHAR2(25);BEGINSELECT

first_name

INTO

v_fnameFROM

employees

WHERE

employee_id=200;DBMS_OUTPUT.PUT_LINE(‘

First

Name

is

:’||v_fname);END;/employees.hire_date%TYPE;employees.salary%TYPE;DECLAREv_emp_hiredatev_emp_salaryBEGINhire_date,

salaryv_emp_hiredate,

v_emp_salaryemployeesemployee_id

=

100;SELECTINTOFROMWHEREEND;/其他DML可以直接在PL/SQL中使用INSERTUPDATEDELETEMERGEINSERTUPDATEDELETEMERGEBEGININSERT

INTO

employees(employee_id,

first_name,

last_name,

email,hire_date,

job_id,

salary)VALUES(employees_seq.NEXTVAL,

'Ruth',

'Cores','RCORES',CURRENT_DATE,

'AD_ASST',

4000);END;/employees.salary%TYPE

:=

800;DECLAREsal_increaseBEGINUPDATE

employeesSET salary

=

salary

+

sal_increaseWHERE job_id

=

'ST_CLERK';END;/employees.department_id%TYPE

:=

10;DECLAREdeptnoBEGINDELETE

FROM

employeesWHERE department_id