目录
- 1、背景
- 2、变量的声明
- 3、if 判断
- 4、case
- 5、循环
- 1、loop 循环
- 2、while 循环
- 3、for循环
- 6、游标
- 1、无参数的游标
- 2、带参数的游标
- 7、执行ddl dml
- 8、存储过程
- 1、无参数的存储过程
- 2、有输入输出参数的存储过程
- 3、merge into 的使用
- 4、测试异常
- 5、bulk into & record
- 1、select into 中使用 bulk into & record
- 2、fetch into 中使用 bulk into & forall
- 6、接收数组参数
- 7、接收数组对象,并将数组对象转换成表使用
- 8、返回多个参数
- 9、程序包 package
- 1、定义包头
- 2、实现包体
- 3、调用包中的方法或存储过程
1、背景
此处简单的记录一下在 oracle中如何使用plsql语法,记录一些简单的例子,防止以后忘记。
2、变量的声明
declare
— 声明变量
v_name varchar2(20);
— 此变量由 select into 赋值
v_man_sex number;
— v_sex 变量的类型和 student表中的 sex 字段的类型一致
v_sex student.sex%TYPE;
— v_row 中保存的是 student表中的一整行字段, 也可以是游标中的一整行
v_row student%rowtype;
— 声明变量并赋值
v_addr varchar2(100) := \’湖北省\’;
— 声明日期变量
v_date date := sysdate;
— 定义一个记录类型
type STUDENT_INFO is record
(
student_id student.student_id%TYPE,
student_name student.student_name%TYPE
);
— 定义基于记录的嵌套表
type nested_student_info is table of STUDENT_INFO;
— 声明变量
student_list nested_student_info;
begin
— 直接赋值
v_name := \’直接赋值\’;
v_date := to_date(\’2023-12-12\’, \’yyyy-mm-dd\’);
— 单个字段语句赋值
select count(*) into v_man_sex from student where sex = 1;
— 多个字段赋值
select student_name,sex into v_name,v_sex from student where student_id = \’S003\’;
— 获取一行数据 ( 此处需要查询出所有的字段,否则可能报错 )
select student_id,student_name,sex,CREATE_TIME into v_row from student where student_id = \’S002\’;
— 打印输出
DBMS_OUTPUT.PUT_LINE(\’日期:\’ || v_date || \’姓名:\’ || v_name || \’,\’ || v_row.STUDENT_NAME || \’ 男生人数:\’ || v_man_sex || \’ 地址:\’ || v_addr );
end;
3、if 判断
统计总共有多少个学生,并进行if判断。
declare
— 声明一个变量,记录有多少个学生
v_student_count number;
begin
— 给 v_student_count 变量赋值
select count(*) into v_student_count from student;
— 执行if判断
if v_student_count > 3 then
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’]>3\’);
elsif v_student_count >=2 then
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’] in [2,3]\’);
else
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’]<2\’);
end if;
end;
4、case
— case
declare
— 声明一个变量,记录有多少个学生
v_student_count number;
begin
— 给 v_student_count 变量赋值
select count(*) into v_student_count from student;
— 执行if判断
case when v_student_count > 3 then
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’]>3\’);
when v_student_count >=2 then
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’] in [2,3]\’);
else
DBMS_OUTPUT.PUT_LINE(\’当前学生数为: [\’ || v_student_count || \’]<2\’);
end case;
end;
5、循环
输出1到100
1、loop 循环
declare
— 定义一个变量并赋值
v_count number := 1;
begin
loop
— 提出条件
exit when v_count > 100;
DBMS_OUTPUT.PUT_LINE(\’当前 count = \’ || v_count);
— v_count 加1
v_count := v_count + 1;
end loop;
end;
2、while 循环
— while 循环
declare
— 定义一个变量并赋值
v_count number := 1;
begin
while v_count <= 100 loop
DBMS_OUTPUT.PUT_LINE(\’当前 count = \’ || v_count);
— v_count 加1
v_count := v_count + 1;
end loop;
end;
3、for循环
— for 循环
declare
— 定义一个变量
v_count number;
begin
for v_count in 1..100 loop
DBMS_OUTPUT.PUT_LINE(\’当前 count = \’ || v_count);
end loop;
end;
6、游标
1、无参数的游标
— 游标
declare
— 声明一个游标
cursor cur_student is select student_id,student_name,sex from student;
— 声明变量
row_cur_student cur_student%rowtype;
begin
— 打开游标
open cur_student;
— 遍历数据
loop
— 获取一行数据
fetch cur_student into row_cur_student;
— 退出
exit when cur_student%NOTFOUND;
— 执行业务逻辑(此句如果移动到exit when上方,则可能会多打印一句)
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || row_cur_student.STUDENT_ID || \’ studentName:\’ || row_cur_student.STUDENT_NAME);
end loop;
— 关闭游标
close cur_student;
end;
2、带参数的游标
declare
— 声明一个游标, 需要传递v_student_id参数
cursor cur_student(v_student_id student.student_id%TYPE) is
select student_id,student_name,sex from student where student_id = v_student_id;
— 声明变量
row_cur_student cur_student%rowtype;
— 此变量通过查询获取值,然后带到游标中
v_query_student_id student.student_id%TYPE;
begin
— 打开游标
–参数传递方式一: open cur_student(\’S001\’);
— 参数传递方式二:
select \’S001\’ into v_query_student_id from dual;
open cur_student(v_query_student_id);
— 遍历数据
loop
— 获取一行数据
fetch cur_student into row_cur_student;
— 退出
exit when cur_student%NOTFOUND;
— 执行业务逻辑(此句如果移动到exit when上方,则可能会多打印一句)
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || row_cur_student.STUDENT_ID || \’ studentName:\’ || row_cur_student.STUDENT_NAME);
end loop;
— 关闭游标
close cur_student;
end;
7、执行ddl dml
需要放到execute immediate中执行,否则会报错。
declare
v_table_name varchar2(20) := \’student_bak\’;
— 拼接一个动态SQL
v_sql varchar2(100);
begin
execute immediate \’create table student_bak as select * from student\’;
execute immediate \’alter table student_bak add new_cloumn varchar2(20)\’;
— 带变量的执行
v_sql := \’drop table \’ || v_table_name;
execute immediate v_sql;
end;
8、存储过程
1、无参数的存储过程
— 无参数的存储过程
create or replace procedure sp_print_all_student
is
— 声明一个游标
cursor c_all_student is select student_id,student_name from student;
— 声明一个变量
row_student c_all_student%rowtype;
begin
— 循环游标
for row_student in c_all_student loop
DBMS_OUTPUT.PUT_LINE(row_student.STUDENT_ID || \’ \’ || row_student.STUDENT_NAME);
end loop;
end;
— 调用
begin
SP_PRINT_ALL_STUDENT();
end;
2、有输入输出参数的存储过程
— 有参数的存储过程
create or replace procedure sp_find_student(/** 输入参数 */ i_student_id in student.student_id%TYPE,
/** 输出参数 */ o_student_name out student.student_name%TYPE)
IS
— 定义变量并赋值
v_student_id varchar2(64) := i_student_id;
begin
DBMS_OUTPUT.PUT_LINE(\’v_student_id:\’ || v_student_id);
— 将查询到的 student_name 赋值到 o_student_name
select student_name into o_student_name from student where student_id = i_student_id;
end;
declare
— 定义一个变量用于接收存储过程的返回值
output_student_name student.student_name%TYPE;
begin
sp_find_student(\’S001\’, output_student_name);
— 输出存储过程的返回值
DBMS_OUTPUT.PUT_LINE(output_student_name);
end;
3、merge into 的使用
存在更新,不存在插入。
create or replace procedure sp_merge_into(i_student_id in varchar2)
IS
begin
— 如果 using 中查询出来的数据,通过 on 条件匹配的话,则更新 student_bak表,否则插入student_bak表
merge into STUDENT_BAK t
using (select * from student where student_id = i_student_id) s
on ( t.student_id = s.student_id )
when matched then update set
— t.STUDENT_ID = s.STUDENT_ID, on中的条件不可更新
t.STUDENT_NAME = s.STUDENT_NAME,
t.SEX = s.SEX,
t.CREATE_TIME = s.CREATE_TIME
when not matched then insert(student_id, student_name, create_time) values (
s.STUDENT_ID,
s.STUDENT_NAME,
s.CREATE_TIME
);
commit ;
end;
4、测试异常
create or replace procedure sp_error
IS
v_num number;
begin
DBMS_OUTPUT.PUT_LINE(\’测试异常\’);
— 产生异常
v_num := 1 / 0;
exception — 存储过程异常
when too_many_rows then
dbms_output.put_line(\’返回值多于1行\’);
when others then
— 异常处理方法,可以是打印错误,然后进行回滚等操作,下面操作一样,看自己情况决定
rollback;
dbms_output.put_line(\’错误码:\’ ||sqlcode);
dbms_output.put_line(\’异常信息:\’ || substr(sqlerrm, 1, 512));
end;
begin
sp_error();
end;
5、bulk into & record
1、select into 中使用 bulk into & record
create or replace procedure sp_bulk_collect_01
IS
— 定义一个记录类型
type STUDENT_INFO is record
(
student_id student.student_id%TYPE,
student_name student.student_name%TYPE
);
— 定义基于记录的嵌套表
type nested_student_info is table of STUDENT_INFO;
— 声明变量
student_list nested_student_info;
begin
— 使用 bulk collect into 将所获取的结果集一次性绑定到记录变量 student_list 中
select student_id,student_name bulk collect into student_list from student;
— 遍历
for i in student_list.first .. student_list.last loop
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || student_list(i).student_id || \’ studentName:\’ || student_list(i).student_name);
end loop;
end;
begin
sp_bulk_collect_01;
end;
2、fetch into 中使用 bulk into & forall
— bulk collect
create or replace procedure sp_bulk_collect_02
IS
— 定义一个游标
cursor cur_student is select student_id,student_name,sex,create_time from student;
— 定义基于游标的嵌套表
type nested_student_info is table of cur_student%rowtype;
— 声明变量
student_list nested_student_info;
begin
— 打开游标
open cur_student;
loop
— 一次获取2条数据插入到 student_list 中
fetch cur_student bulk collect into student_list limit 2;
— 退出
–exit when student_list%notfound; 不可使用这种方式
exit when student_list.count = 0;
— 输出
for i in student_list.first .. student_list.last loop
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || student_list(i).student_id || \’ studentName:\’ || student_list(i).student_name);
end loop;
— 使用 forall 更新数据, 可以将多个dml语句批量发送给SQL引擎,提高执行效率。
forall i in student_list.first .. student_list.last
update student set student_name = student_list(i).STUDENT_NAME || \’_update\’ where student_id = student_list(i).STUDENT_ID;
commit ;
end loop;
— 关闭游标
close cur_student;
end;
begin
sp_bulk_collect_02;
end;
6、接收数组参数
— 创建StudentIdList数组的长度是4,每一项最多存20个字符
create or replace type StudentIdList as varray(4) of varchar2(20);
— 创建存储过程,接收数组参数
create or replace procedure sp_param_list(studentIdList in StudentIdList)
is
begin
for i in 1..studentIdList.COUNT loop
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || studentIdList(i));
end loop;
end;
declare
begin
sp_param_list(STUDENTIDLIST(\’d\’,\’c\’,\’S001\’,\’S0021222222222233\’));
end;
7、接收数组对象,并将数组对象转换成表使用
— 创建数据库对象
create or replace type StudentInfo is object(
studentId varchar2(64),
studentName varchar2(64)
);
— 创建数组对象
create or replace type StudentInfoArr as table of StudentInfo;
— 创建存储过程
create or replace procedure sp_param_list_02(arr in StudentInfoArr)
is
— 声明一个变量,记录传递进来的arr的数量
v_student_count number := 0;
begin
— 传递进来的数组转换成使用
select count(*) into v_student_count from table(cast(arr AS StudentInfoArr))
where studentId like \’S%\’;
DBMS_OUTPUT.PUT_LINE(\’传递进来学生学号以S开头的学生有: \’ || v_student_count || \’个\’);
— 输出列表参数
for i in 1..arr.COUNT loop
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || arr(i).studentId || \’ studentName:\’ || arr(i).studentName);
end loop;
end;
declare
begin
sp_param_list_02(arr => StudentInfoArr(StudentInfo(\’S001\’,\’张三\’),StudentInfo(\’S002\’,\’李四\’)));
end;
8、返回多个参数
create or replace procedure sp_return_value(stuInfoList out Sys_Refcursor)
IS
begin
open stuInfoList for select STUDENT_ID,STUDENT_NAME,SEX from STUDENT;
end;
declare
stu Sys_Refcursor;
v_student_id STUDENT.STUDENT_ID%TYPE;
v_student_name STUDENT.STUDENT_NAME%TYPE;
v_sex STUDENT.SEX%TYPE;
begin
SP_RETURN_VALUE( stu);
loop
fetch stu into v_student_id,v_student_name,v_sex;
exit when stu%notfound;
DBMS_OUTPUT.PUT_LINE(\’studentId:\’ || v_student_id || \’ studentName: \’ || v_student_name);
end loop;
end;
9、程序包 package
1、定义包头
包头可以简单的理解java中的接口。
create or replace package pkg_huan as
v_pkg_name varchar2(30) := \’pkg_huan\’;
function add(param1 in number, param2 in number) return number;
procedure sp_pkg_01;
procedure sp_pkg_02(param1 in varchar2);
end pkg_huan;
2、实现包体
包体可以简单的理解java中的实现接口的类。
create or replace package body pkg_huan as
— 实现function
function add(param1 in number, param2 in number) return number IS
begin
return param1 + param2;
end;
— 实现无参数的存储过程
procedure sp_pkg_01 as
begin
DBMS_OUTPUT.PUT_LINE(\’package name:\’ || v_pkg_name || \’procedure name: sp_pkg_01\’);
end;
— 实现有参数的存储过程
procedure sp_pkg_02(param1 in varchar2) as
begin
DBMS_OUTPUT.PUT_LINE(\’param1:\’ || param1);
end;
end;
3、调用包中的方法或存储过程
begin
— 调用方法
DBMS_OUTPUT.PUT_LINE(\’1+2=\’ || PKG_HUAN.add(1,2));
— 调用无参数的存储过程
PKG_HUAN.sp_pkg_01();
— 调用有参数的存储过程
PKG_HUAN.sp_pkg_02(12);
end;
以上就是PLSQL一些常用知识点梳理总结的详细内容,更多关于PLSQL常用知识点的资料请关注悠久资源其它相关文章!