Question

一直在挣扎，希望得到一些帮助在轨道上运行了很多数学函数并找到了虚假的结果后，我决定爬下来在数据库中执行它，发现它对我来说都是非常可行的，但是当我到达第二个函数时以下错误：

PG :: UndefinedFunction：错误：函数updown（整数）不存在第3行：SELECT＆＃34; updown＆＃34; （滞后（updown）结束（按id排序））table_nam ... ^提示：没有函数匹配给定的名称和参数类型。

迁移：

class CreateSmoothings < ActiveRecord::Migration
def change
create_table :smoothings do |t|
  t.decimal :firstsmprice,    :precision => 8,    :scale => 6
  t.decimal :finalsmprice,    :precision => 8,    :scale => 6
  t.decimal :firstsmdelta,    :precision => 8,    :scale => 6
  t.decimal :finalsmdelta,    :precision => 8,    :scale => 6
  t.integer :updown,          :null => false,     :default => 0
  t.integer :posture
  t.integer :step
  t.references :usdzar,       index: true,        foreign_key: true
  t.references :smoothval,    index: true,        foreign_key: true

  t.timestamps null: false
end
add_index :smoothings, :finalsmprice
end
end

我有一个更新控制器，用于设置来自另一个表的平滑数据，这是触发器触发的时间。第一个触发器就像一个魅力。这是控制器动作，然后是触发器和功能。

#POST / smoothings工作并将所有数据插入到平滑表

def create

# Do the 1st and 2nd SMOOTHINGS
# Get the row with the smoothval_id parameter to use these
sv = Smoothval.find(smoothing_params[:smoothval_id])
fval = sv.fval
sval = sv.sval
svid = sv.id

toremove = Smoothing.where(:smoothval_id => sv.id)
toremove.destroy_all

# For every entry in the table do:
collection = Usdzar.all
collection.each_with_index do |usdzar, i|

    # Declare the previous variables required for id = 1 as
    # the calculation cannot be done as it has no previous id
    # I am sure this can be refactored
    if usdzar.id == 1
      prevprice = usdzar.price
      prevfirstsmprice = usdzar.price
      prevfinalsmprice = usdzar.price
    else
      prevprice = collection[i-1].price
      prevfirstsmprice = Smoothing.last.firstsmprice
      prevfinalsmprice = Smoothing.last.finalsmprice
    end

    # Do the smoothing calcs for the first smoothing using fval (first value)
    firstsmprice = (((fval * usdzar.delta)/100) + prevprice)

    # Find the difference of the current and previous of the first smoothing
    firstsmdelta = firstsmprice - prevfirstsmprice

    # Do the final smooting with the fval
    finalsmprice = ((sval * firstsmdelta)/100) + prevfirstsmprice

    # Find the differance of the current and previous of the second smoothing
    finalsmdelta = finalsmprice - prevfinalsmprice

    # Create the rows at end of iteration
    Smoothing.create!(
      usdzar_id: usdzar.id,
      smoothval_id: sv.id,
      firstsmprice: firstsmprice,
      firstsmdelta: firstsmdelta,
      finalsmprice: finalsmprice,
      finalsmdelta: finalsmdelta
    )
end
redirect_to smoothings_url, notice: 'Old smoothings removed and new smoothings successfully created.'

触发功能和触发器有效： - ）

CREATE TRIGGER a_smoothings_trigger
AFTER INSERT
ON smoothings
FOR EACH ROW
EXECUTE PROCEDURE make_updowns_trg();

CREATE FUNCTION make_updowns_trg() 
RETURNS trigger
LANGUAGE 'plpgsql'
AS $BODY$
BEGIN
update smoothings
set updown =  case when  (finalsmdelta < 0) then 1
                when  (finalsmdelta > 0 ) then 0
          else 2 end;
RETURN NULL; 
END
$BODY$;

这（上述）运行良好。我接下来要做的是通过另一个触发器和函数扩展函数（现在知道它们按字母顺序运行触发器/功能用于采取＆＃34; updown＆＃34; （0,1或2：向上，向下或相同是轨道中的枚举）和：

如果updown和next updown相同，则更新为2（中间）如果updown大于next＆＃34; updown＆＃34;更新为1（高）如果updown小于下一个＆＃34; updown＆＃34;更新为0（低）

CREATE FUNCTION public.make_high_lows_trg()
RETURNS trigger
LANGUAGE 'plpgsql'
COST 100.0
VOLATILE NOT LEAKPROOF 
AS $BODY$
BEGIN
WITH next_updown AS
(SELECT updown (lag(updown) over (order by id)) table_name FROM smoothings 
ORDER BY id DESC) 
update smoothings
set posture =  case when updown < next_updown then 1
                when updown > next_updown then 0
          else 2 end;
RETURN NULL; 
END
$BODY$;

CREATE TRIGGER b_smoothings_trigger
AFTER INSERT
ON public.smoothings
FOR EACH ROW
EXECUTE PROCEDURE public.make_high_lows_trg();

控制器的模型：

class Smoothing < ActiveRecord::Base

enum updown: [:up, :down, :same]
enum posture: [:high, :low, :inbetween]

belongs_to :usdzar
belongs_to :smoothval

end

我把这一切都在控制器中运行，因为我的模型方法编码非常糟糕并且一切都在运行，但是在测试后发现数据非常不可靠。在此先感谢您的帮助。我对Postgres中的函数数量感到震惊，当我遇到窗口函数时认为它是合适的但可以克服障碍。我知道（来自psql文档）你不能把滞后/主导窗口放到函数的更新部分，但是显然有关于如何正确执行sql块的问题

此查询在运行第一个查询后运行，但如何更新表格：

with myUpdowns as (
 Select id, updown, Lag(updown) over (order by id desc) next_updown from smoothings
)
select *
from myUpdowns
where updown < next_updown;

现在我得到了一个正确更新的高点：我现在正试图做到高点的全面传播。低和中间（0,1和2）。如果您有任何建议，我很乐意听到。向表中添加高位的更新触发器如下所示：

CREATE FUNCTION make_high_lows_trg()
RETURNS trigger
LANGUAGE 'plpgsql'
AS $BODY$
BEGIN

UPDATE smoothings

SET posture = 0
FROM (
Select id, updown, Lag(updown) over (order by id desc) next_updown from smoothings
) as highs
WHERE highs.updown < highs.next_updown 
AND smoothings.id = highs.id;

RETURN NULL; 
END
$BODY$;

触发器：

CREATE TRIGGER b_smoothings_trigger
AFTER INSERT
ON smoothings
FOR EACH ROW
EXECUTE PROCEDURE make_high_lows_trg();

嗯，现在如何做低和中间，实际上只是高低都很好

Postgres 9.5.4更新触发器功能窗口（滞后和超前）

0 个答案: