開發動態SQL 學習筆記

當編寫動態SQL程序時，根據葯處理SQL的不同，可以使用三种不同類型的動態SQL方法：

（1）使用EXECUTE IMMEDIATE語句

（2）使用OPEN FOR，FETCH和CLOSE語句

（3）使用批量動態SQL

一、處理非查詢語句

1.使用EXECUTE IMMEDIATE處理DDL操作

SQL> create or replace procedure drop_table(table_name varchar2)
2 is
3 sql_statement varchar2(100);
4 begin
5 sql_statement:='drop table '||table_name;
6 execute immediate sql_statement;
7 end;
8 /

Procedure created.

SQL> exec drop_table('TEST1');

PL/SQL procedure successfully completed.

2.使用EXECUTE IMMEDIATE處理DCL操作

SQL> conn system/system
Connected.
SQL> create or replace procedure grant_sys_prive(priv varchar2,username varchar2)
2 is
3 sql_statement varchar2(100);
4 begin
5 sql_statement:='grant '||priv||' to '||username;
6 execute immediate sql_statement;
7 end;
8 /

Procedure created.

SQL> exec grant_sys_priv('create session','SCOTT');

PL/SQL procedure successfully completed.

3.使用EXECUTE IMMEDIATE處理DML操作

3.1 處理無占位符和RETURNING子句的DML語句

SQL> declare
2 sql_stat varchar2(100);
3 begin
4 sql_stat:='update emp set sal=sal*1.1 where deptno=30';
5 execute immediate sql_stat;
6 end;
7 /

PL/SQL procedure successfully completed.

3.2 處理包含占位符的DML語句

1 declare
2 sql_stat varchar2(100);
3 begin
4 sql_stat:='update emp set sal=sal*(1+:percent/100)'
5 ||' where deptno=:dno';
6 execute immediate sql_stat using &percent,&dno;
7* end;
SQL> /
Enter value for percent: 15
Enter value for dno: 30
old 6: execute immediate sql_stat using &percent,&dno;
new 6: execute immediate sql_stat using 15,30;

PL/SQL procedure successfully completed.

3.3 處理包含RETURNING子句的DML語句

1 declare
2 salary number;
3 sql_stat varchar2(100);
4 begin
5 sql_stat:='update emp set sal=sal*(1+:percent/100)'
6 ||' where empno=:eno returning sal into :salary';
7 execute immediate sql_stat using &percent,&eno
8 returning into salary;
9 dbms_output.put_line('NEW SALARY:'||salary);
10* end;
SQL> /
Enter value for percent: 15
Enter value for eno: 7788
old 7: execute immediate sql_stat using &percent,&eno
new 7: execute immediate sql_stat using 15,7788
NEW SALARY:3967.5

PL/SQL procedure successfully completed.

4.使用EXECUTE IMMEDIATE處理單行查詢

SQL> declare
2 sql_stat varchar2(100);
3 emp_record emp%rowtype;
4 begin
5 sql_stat:='select * from emp where empno=:eno';
6 execute immediate sql_stat into emp_record using &eno;
7 dbms_output.put_line('Employee : '||emp_record.ename||'''s salary is : '||emp_record.sal);
8 end;
9 /
Enter value for eno: 7369
old 6: execute immediate sql_stat into emp_record using &eno;
new 6: execute immediate sql_stat into emp_record using 7369;
Employee : SMITH's salary is : 920

PL/SQL procedure successfully completed.

二、處理多行查詢語句

使用OPEN FOR，FETCH和CLOSE語句

1 declare
2 type empcurtype is ref cursor;
3 emp_cur empcurtype;
4 emp_record emp%rowtype;
5 sql_stat varchar2(200);
6 begin
7 sql_stat:='select * from emp where deptno=:dno';
8 open emp_cur for sql_stat using &dno;
9 loop
10 fetch emp_cur into emp_record;
11 exit when emp_cur%notfound;
12 dbms_output.put_line('Employee:'||emp_record.ename||',salary:'||emp_record.sal);
13 end loop;
14* end;
SQL> /
Enter value for dno: 10
old 8: open emp_cur for sql_stat using &dno;
new 8: open emp_cur for sql_stat using 10;
Employee:CLARK,salary:2450
Employee:KING,salary:5000
Employee:MILLER,salary:1300

PL/SQL procedure successfully completed.

三、在動態SQL中使用BULK子句

1.在EXECUTE IMMEDIATE語句中使用BULK子句

1.1 使用BULK子句處理DML語句返回子句

SQL> declare
2 type ename_table_type is table of emp.ename%type
3 index by binary_integer;
4 type sal_table_type is table of emp.sal%type
5 index by binary_integer;
6 ename_table ename_table_type;
7 sal_table sal_table_type;
8 sql_stat varchar(200);
9 begin
10 sql_stat:='update emp set sal=sal*(1+:percent/100)'
11 ||' where deptno=:dno'
12 ||' returning ename,sal into :name,:salary';
13 execute immediate sql_stat using &percent,&dno
14 returning bulk collect into ename_table,sal_table;
15 for i in 1..ename_table.count loop
16 dbms_output.put_line('employee name is :'||ename_table(i)
17 ||' employee salary is :'||sal_table(i));
18 end loop;
19 end;
20 /
Enter value for percent: 15
Enter value for dno: 20
old 13: execute immediate sql_stat using &percent,&dno
new 13: execute immediate sql_stat using 15,20
employee name is :SMITH employee salary is :1058
employee name is :JONES employee salary is :3934.44
employee name is :SCOTT employee salary is :3967.5
employee name is :ADAMS employee salary is :1454.75
employee name is :FORD employee salary is :3967.5
employee name is :NAME employee salary is :3967.5

PL/SQL procedure successfully completed.

1.2 使用BULK子句處理多行查詢

1 declare
2 type ename_table_type is table of emp.ename%type
3 index by binary_integer;
4 ename_table ename_table_type;
5 sql_stat varchar2(100);
6 begin
7 sql_stat:='select ename from emp where deptno=:dno';
8 execute immediate sql_stat bulk collect into ename_table using &dno;
9 for i in 1..ename_table.count loop
10 dbms_output.put_line('Employee''s name is '||ename_table(i));
11 end loop;
12* end;
SQL> /
Enter value for dno: 10
old 8: execute immediate sql_stat bulk collect into ename_table using &dno;
new 8: execute immediate sql_stat bulk collect into ename_table using 10;
Employee's name is CLARK
Employee's name is KING
Employee's name is MILLER

PL/SQL procedure successfully completed.

2.在FETCH語句中使用BULK子句

SQL> set pagesize 300
SQL> set linesize 300
SQL> set timing on
SQL> set serveroutput on size 5000

1 declare
2 type empcurtype is ref cursor;
3 empcur empcurtype;
4 type ename_table_type is table of emp.ename%type
5 index by binary_integer;
6 ename_table ename_table_type;
7 sql_stat varchar2(200);
8 begin
9 sql_stat:='select ename from emp where job=:tt';
10 open empcur for sql_stat using '&job';
11 fetch empcur bulk collect into ename_table;
12 for i in 1..ename_table.count loop
13 dbms_output.put_line(ename_table(i));
14 end loop;
15* end;
SQL> /
Enter value for job: CLERK
old 10: open empcur for sql_stat using '&job';
new 10: open empcur for sql_stat using 'CLERK';
SMITH
ADAMS
JAMES
MILLER

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.03

3.在FORALL語句中使用BULK子句

1 declare
2 type ename_table_type is table of emp.ename%type;
3 type sal_table_type is table of emp.sal%type;
4 ename_table ename_table_type;
5 sal_table sal_table_type;
6 sql_stat varchar2(100);
7 begin
8 ename_table:=ename_table_type('SCOTT','SMITH','CLARK');
9 sql_stat:='update emp set sal=sal*1.1 where ename=:name'
10 ||' returning sal into :salary';
11 forall i in 1..ename_table.count
12 execute immediate sql_stat using ename_table(i)
13 returning bulk collect into sal_table;
14 for j in 1..ename_table.count loop
15 dbms_output.put_line('Employee: '||ename_table(j)||'''s new salary is '||sal_table(j));
16 end loop;
17* end;
SQL> /
Employee: SCOTT's new salary is 3795
Employee: SMITH's new salary is 880
Employee: CLARK's new salary is 2695

PL/SQL procedure successfully completed.