带有动态 SQL 语句的游标 For 循环

2021-12-24 00:00:00 dynamic database-cursor oracle plsql

有没有办法用动态 SQL 语句执行 Cursor For 循环?

Is there a way to perform a Cursor For Loop with an dynamic SQL-statement?

如果我不想声明记录，我可以这样做(仅当我声明了游标..):

If I don't want to declare a record I can do something like this (only if I declared the cursor..):

For I in cuSelect Loop
  dbms_output.put_line(I.NAME);
End Loop;

我可以为动态 SQL 语句打开一个游标:

And I can open a cursor for a dynamic SQL-statement:

Open cuSelect For 'Select * From TAB_X';
Fetch ceSelect Into recSelect;
Close cuSelect;

但要做到这一点，我必须先声明 Record.

But to do that I have to first declare the Record.

现在我的问题是我必须为一个非常大和复杂的动态 SQL 语句打开 Cursor.记录的结构未知.有没有办法打开一个变量游标并用未声明"的记录遍历它?

Now my problem is that I have to open the Cursor for a very big and complicated dynamic SQL-statement. The structure of the record is unknown. Is there a way to open a variable cursor and iterate through it with an "undeclared" record?

推荐答案

我认为你可以用 DBMS_SQL 包做你想做的事.

I think you can do what you want with DBMS_SQL package.

您还可以检查这些:

  • 使用动态 SQL
  • COLUMN_VALUE 程序

例如:

declare
  TYPE curtype IS REF CURSOR;
  src_cur      curtype;
  curid        NUMBER;
  namevar  VARCHAR2(50);
  numvar   NUMBER;
  datevar  DATE;
  desctab  DBMS_SQL.DESC_TAB;
  colcnt   NUMBER;
  dsql varchar2(1000) := 'select card_no from card_table where rownum = 1';
begin
  OPEN src_cur FOR dsql;

  -- Switch from native dynamic SQL to DBMS_SQL package.
  curid := DBMS_SQL.TO_CURSOR_NUMBER(src_cur);
  DBMS_SQL.DESCRIBE_COLUMNS(curid, colcnt, desctab);

  -- Define columns.
  FOR i IN 1 .. colcnt LOOP
    IF desctab(i).col_type = 2 THEN
      DBMS_SQL.DEFINE_COLUMN(curid, i, numvar);
    ELSIF desctab(i).col_type = 12 THEN
      DBMS_SQL.DEFINE_COLUMN(curid, i, datevar);
    ELSE
      DBMS_SQL.DEFINE_COLUMN(curid, i, namevar, 50);
    END IF;
  END LOOP;

  -- Fetch rows with DBMS_SQL package.
  WHILE DBMS_SQL.FETCH_ROWS(curid) > 0 LOOP
    FOR i IN 1 .. colcnt LOOP
      IF (desctab(i).col_type = 1) THEN
        DBMS_SQL.COLUMN_VALUE(curid, i, namevar);
        dbms_output.put_line(namevar);
      ELSIF (desctab(i).col_type = 2) THEN
        DBMS_SQL.COLUMN_VALUE(curid, i, numvar);
        dbms_output.put_line(numvar);
      ELSIF (desctab(i).col_type = 12) THEN
        DBMS_SQL.COLUMN_VALUE(curid, i, datevar);
        dbms_output.put_line(datevar);
      END IF;
    END LOOP;
  END LOOP;

  DBMS_SQL.CLOSE_CURSOR(curid);

end;

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