Oralce 存储过程 cursor、type x_cur is ref cursor、sys_refcursor 静态游标、强类型 弱类型动态游标、静态SQL 动态SQL 结合使用总结

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直接上代码，使用的开发环境：

Oracle Database 11g Release 2(11.2.0.4.0) - Enterprise Edition，

PL/SQL Develop 12.0.7，Instantclient_12_2；

PL/SQL Develop -> New -> Test Windoow：

游标 动态 遍历 cursor 匿名块.tst：

-- Created on 2018/12/17 by TECH01 
declare

    cursor cus_cur(in_id number) return pre_preorder%rowtype
    is
        select * from pre_preorder where id < in_id;
    cus_row pre_preorder%rowtype;

begin
    
    open cus_cur(1200);

    dbms_output.put_line(cus_cur%ROWCOUNT);     --如果游标没有open cus_cur(1200); ORA-01001: invalid cursor
    
    if cus_cur%found = true then
        dbms_output.put_line('cus_cur%found = true');
    end if;
    
    if cus_cur%notfound = true then
        dbms_output.put_line('cus_cur%notfound = true');
    end if;
    
    loop
        fetch cus_cur into cus_row; --ORA-01001: invalid cursor
        
        if cus_cur%found = true then
            dbms_output.put_line('loop fetch cus_cur%found = true');
        end if;
            
        if cus_cur%notfound = true then
            dbms_output.put_line('loop fetch cus_cur%notfound = true');
        end if;
        
        exit when cus_cur%notfound;
        
    end loop;

    dbms_output.put_line(cus_cur%ROWCOUNT);

    close cus_cur;

    --dbms_output.put_line(cus_cur%ROWCOUNT );  --ORA-01001: invalid cursor

end;





DBMS Output:

0
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%found = true
loop fetch cus_cur%notfound = true
14

游标 动态 遍历 ref cursor 匿名块.tst：

-- Created on 2018/12/17 by TECH01 
declare 
  -- Local variables here
  --type cus_cur_type is ref cursor return pre_preorder%rowtype; 
  type cus_cur_type is ref cursor;
  cus_cur cus_cur_type;
  cus_row pre_preorder%rowtype;
  l_id integer := 1200;
begin
  --open cus_cur for select * from pre_preorder where id < :v_id using l_id;  --PL/SQL: ORA-00933: SQL command not properly ended
  open cus_cur for 'select * from pre_preorder where id < :v_id' using l_id;  --ref cursor return pre_preorder%rowtype; 不可以用在动态SQL语句中PLS-00455: cursor 'CUS_CUR' cannot be used in dynamic SQL OPEN statement
  --open cus_cur for select * from pre_preorder where id < l_id;              --ref cursor return pre_preorder%rowtype; 可以用在静态SQL语句中
  
  dbms_output.put_line(cus_cur%ROWCOUNT );
  
  loop 
      fetch cus_cur into cus_row;
      exit when cus_cur%notfound;
  end loop;
  
  dbms_output.put_line(cus_cur%rowcount);
  
  
  open cus_cur for select * from pre_preorder where id < 1300;
  
  loop 
      fetch cus_cur into cus_row;
      exit when cus_cur%notfound;
  end loop;
  
  dbms_output.put_line(cus_cur%rowcount);
  
  
  close cus_cur;
  
  --dbms_output.put_line(cus_cur%rowcount);   --ORA-01001: invalid cursor
  
end;

游标 动态 遍历 sys_refcursor 匿名块.tst：

-- Created on 2018/12/17 by TECH01 
declare

    cus_cur sys_refcursor;--return pre_preorder%rowtype;  --PLS-00103: Encountered the symbol "RETURN" when expecting one of the following: := . ( @ % ; not null range default character, The symbol ";" was substituted for "RETURN" to continue.

    cus_row pre_preorder%rowtype;
    l_id integer := 1200;
begin
    --open cus_cur for select * from pre_preorder where id < :v_id using l_id;    --PL/SQL: ORA-00933: SQL command not properly ended
    --open cus_cur for 'select * from pre_preorder where id < :v_id' using l_id;  --PLS-00455: cursor 'CUS_CUR' cannot be used in dynamic SQL OPEN statement
    --open cus_cur for 'select * from pre_preorder where id < l_id';              --ORA-00904: "L_ID": invalid identifier
    open cus_cur for select * from pre_preorder where id < l_id;                  --sys_refcursor可以用在静态SQL语句中
    --open cus_cur for 'select * from pre_preorder where id < :v_id' using l_id;  --sys_refcursor可以用在动态SQL语句中
    
    
    
    dbms_output.put_line(cus_cur%ROWCOUNT);

    loop
        fetch cus_cur
            into cus_row;
        exit when cus_cur%notfound;
    end loop;

    dbms_output.put_line(cus_cur%ROWCOUNT);

    close cus_cur;

    --dbms_output.put_line(cus_cur%ROWCOUNT );  --ORA-01001: invalid cursor

end;

综上总结：

1. 只有 sys_refcursor return pre_preorder%rowtype;  

不能使用强类型的动态游标，汇报以下错误：

PLS-00103: Encountered the symbol "RETURN" when expecting one of the following: := . ( @ % ; not null range default character, The symbol ";" was substituted for "RETURN" to continue.

2. ref cursor return pre_preorder%rowtype;

不可以用在动态SQL语句中PLS-00455: cursor 'CUS_CUR' cannot be used in dynamic SQL OPEN statement；

可以用在静态SQL语句中

3. sys_refcursor

可以用在静态SQL语句中；

可以用在动态SQL语句中；

3. x_curcur%ROWCOUNT 可以理解为是一个计数器，初始值为0，每fetch游标x_curcur一次，计数器 +1；

4. x_cur%found 在fetch游标x_curcur前为false，fetch到数据行时为true，直到fetch不到行数据时值为false；

5.x_cur%notfound  在fetch游标x_curcur前为false，fetch到数据行时为false，直到fetch不到行数据时值为true；

参考:

https://blog.csdn.net/zx695370759/article/details/79200913

强类型的动态游标和弱类型的动态游标区别

2018年01月29日 22:58:22 穿毛衣的程序猿 阅读数：130

1、简单的来说：强类型的动态游标是指带有return返回语句的，而弱类型的动态游标是指不带return语句的（也即，弱类型的动态游标可以与任何查询语句匹配，但是强类型的动态游标只能与特定的查询语句匹配。）

2、个人理解：强类型的有点像java中使用了泛型一样对其进行了限制，而弱类型的就像object类型。