更新 PL/pgSQL 中的一整行 [英] UPDATE a whole row in PL/pgSQL

问题描述

我有plpgsql函数:

I have plpgsql function:

CREATE OR REPLACE FUNCTION test() RETURNS VOID AS
$$
DECLARE
    my_row my_table%ROWTYPE;
BEGIN
    SELECT * INTO my_row FROM my_table WHERE id='1';
    my_row.date := now();
END;
$$ LANGUAGE plpgsql;

我想知道是否可以直接更新 my_row 记录.

I would like to know if it's possible to directly UPDATE my_row record.

我现在发现的唯一方法是:

The only way I've found to do it now is:

UPDATE my_table SET date=now() WHERE id='1';

请注意，这只是一个示例函数，真正的函数远比这复杂.

Note this is only an example function, the real one is far more complex than this.

我使用的是 PostgreSQL 9.2.

I'm using PostgreSQL 9.2.

更新:

对不起，我想说的是:

SELECT * INTO my_row FROM my_table INTO my_row WHERE id='1';
make_lots_of_complicated_modifications_to(my_row, other_complex_parameters);
UPDATE my_row;

即使用 my_row 将信息持久保存在基础表中.我有很多参数要更新.

I.e. Use my_row to persist information in the underlying table. I have lots of parameters to update.

推荐答案

我想知道是否可以直接更新my_row"记录.

I would like to know if it's possible to directly update "my_row" record.

是的.
您可以在 plpgsql 中更新行或记录类型的列 - 就像您拥有它一样.显然它应该可以工作?

It is.
You can update columns of a row or record type in plpgsql - just like you have it. It should be working, obviously?

这当然会更新基础表，而不是变量！

This would update the underlying table, of course, not the variable!

UPDATE my_table SET date=now() WHERE id='1';

你在这里混淆了两件事......

You are confusing two things here ...

我认为 PostgreSQL 中没有可以 UPDATE 整行的语法.您可以UPDATE列列表，不过.考虑这个演示:

I don't think there is syntax in PostgreSQL that can UPDATE a whole row. You can UPDATE a column list, though. Consider this demo:

注意我如何使用 thedate 而不是 date 作为列名，date 是一个 每个 SQL 标准中的保留字 和 PostgreSQL 中的类型名称.

Note how I use thedate instead of date as column name, date is a reserved word in every SQL standard and a type name in PostgreSQL.

CREATE TEMP TABLE my_table (id serial, thedate date);
INSERT INTO my_table(thedate) VALUES (now());

CREATE OR REPLACE FUNCTION test_up()
  RETURNS void LANGUAGE plpgsql AS
$func$
DECLARE
    _r my_table;
BEGIN
   SELECT * INTO _r FROM my_table WHERE id = 1;
   _r.thedate := now()::date + 5 ;

   UPDATE my_table t
    -- explicit list of columns to be to updated
   SET   (id, thedate) = (_r.id, _r.thedate)
   WHERE  t.id = 1;
END
$func$;

SELECT test_up();
SELECT * FROM my_table;

但是，您可以INSERT 整行 轻松.只是不要为表格提供列列表(您通常应该这样做，但在这种情况下完全可以，不要这样做).

However, you can INSERT a whole row easily. Just don't supply a column list for the table (which you normally should, but in this case it is perfectly ok, not to).

作为一个 UPDATE 在内部是一个 DELETE 后跟一个 INSERT 无论如何，一个函数会自动将所有内容封装在一个事务中，我不'看不出来，为什么你不能改用这个:

As an UPDATE is internally a DELETE followed by an INSERT anyway, and a function automatically encapsulates everything in a transaction, I don't see, why you couldn't use this instead:

CREATE OR REPLACE FUNCTION x.test_ delins()
  RETURNS void LANGUAGE plpgsql AS
$func$
DECLARE
    _r my_table;
BEGIN
   SELECT * INTO _r
   FROM my_table WHERE id = 1;
   _r.thedate := now()::date + 10;

   DELETE FROM my_table t WHERE t.id = 1;
   INSERT INTO my_table SELECT _r.*;
END
$func$;

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