![](/img/trans.png)
[英]PostgreSQL PL/Python: call stored procedure in virtualenv
[英]In a PostgreSQL CHECK constraint using a boolean stored procedure written in PL/Python, can the detail of the error message be updated?
qustion在(盡管很長)的標題中。 我有這樣的代碼:
-- create the tables for models
CREATE TABLE invoice(
id SERIAL PRIMARY KEY,
value VARCHAR(8)
CONSTRAINT valid_money CHECK(validate_invoice_money(value))
);
用這個程序:
CREATE OR REPLACE FUNCTION validate_invoice_money(test VARCHAR) RETURNS BOOLEAN AS $$
import plpy
import re
if (re.match("^[0-9]+\\.[0-9]{2}$", test) == None):
return False
return True
$$ LANGUAGE plpython3u IMMUTABLE;
(這個例子的細節並不重要,我知道有更好的方法來驗證一個值,比如使用MONEY
類型。)
當嘗試插入未通過此檢查時,我收到以下錯誤:
ERROR : new row for relation "invoice" violates check constraint "valid_model"
DETAIL : Failing row contains (1, "notvalid").
(錯誤/詳細描述符是我自己的代碼,但PostgreSQL錯誤有錯誤,並提供詳細信息字段。)
有沒有辦法讓我從Python程序中更改此錯誤的“詳細信息”部分?
在Postgres 9.6+中,您可以使用實用程序函數從plpython函數中提取詳細消息,例如:
CREATE OR REPLACE FUNCTION validate_invoice_money(test VARCHAR)
RETURNS BOOLEAN AS $$
import re
if (re.match("^[0-9]+\\.[0-9]{2}$", test) == None):
plpy.error("custom exception message",
detail="some info about exception",
hint="hint for users")
return False
return True
$$ LANGUAGE plpython3u IMMUTABLE;
insert into invoice
values (default, 'notvalid');
ERROR: plpy.Error: custom exception message
DETAIL: some info about exception
HINT: hint for users
CONTEXT: Traceback (most recent call last):
PL/Python function "validate_invoice_money", line 8, in <module>
hint="hint for users")
PL/Python function "validate_invoice_money"
你不需要額外的語言; 你可以使用普通正則表達式來限制值:
-- create the tables for models
CREATE TABLE invoice(
id SERIAL PRIMARY KEY,
val VARCHAR(8)
-- CONSTRAINT valid_money CHECK(validate_invoice_money(value))
CONSTRAINT valid_money CHECK(val ~ '^[0-9]+\.[0-9]{2}$' )
);
INSERT INTO invoice (val) VALUES ('0123.98' ); -- success
INSERT INTO invoice (val) VALUES ('a123.98' ); -- failure
SELECT * FROM invoice;
結果:
CREATE TABLE
INSERT 0 1
ERROR: new row for relation "invoice" violates check constraint "valid_money"
DETAIL: Failing row contains (2, a123.98).
id | val
----+---------
1 | 0123.98
(1 row)
並回答這個問題:我認為您無法獲得有關約束違規的其他信息。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.