Question

如果一项程序在中间失败,从“特殊产品”开始起,当时的变化是暗中进行的,或者我们是否必须起草任何明确的法典,以确保特殊产品仅在交易中进行?

Answer 1

该术语经常被错误地用于指Functions (CREATE FUNCTION),该词提供了与RDBMS提供的其他“存储程序”相同的许多功能(以及更多的功能)。

Real stored procedures (:CREATE PROCEDURE) 采用ISO/IEC标准中规定的标准。 Postgres 11。主要差异(除其他之外)是交易处理。见:

其中有的always在交易中运行. 。手册:

PostgreSQL actually treats every SQL statement as being executed within a transaction. If you do not issue a BEGIN command, then each individual statement has an implicit BEGIN and (if successful) COMMIT wrapped around it.

Functions

页: 1 页: 1

而PL/pgSQL.

By default, any error occurring in a PL/pgSQL function aborts execution of the function and the surrounding transaction. You can trap errors and recover from them by using a BEGIN block with an EXCEPTION clause.

Do not confuse

Procedures

......允许<代码>COMMIT——立即启动新的交易。

A new transaction starts out with default transaction characteristics such as transaction isolation level. In cases where transactions are committed in a loop, it might be desirable to start new transactions automatically with the same characteristics as the previous one. The commands COMMIT AND CHAIN and ROLLBACK AND CHAIN accomplish this.

Exceptions

诸如VACUUM、、CRE DATABASE或CREATE INDEX CONCURRENTLY等指挥系统在交易环境下运作,不得在任何内部进行。

Some things can never be rolled back, including:

用于记录档案的数据

对顺序的改动:

Important: Some PostgreSQL data types and functions have special rules regarding transactional behavior. In particular, changes made to a sequence (and therefore the counter of a column declared using serial) are immediately visible to all other transactions and are not rolled back if the transaction that made the changes aborts.

发言稿(原

dblink calls (or similar). 见:

Does Postgres support nested or autonomous transactions?

Answer 2

如果你使用以下14项程序:

CREATE OR REPLACE PROCEDURE test_error(schema_name text)
LANGUAGE plpgsql
AS
$$
declare
<declare any vars that you need>
BEGIN
<do your thing>
END
$$;

就所有实际用途而言,在<条码>BEGIN和<条码>栏目之间书写的代码在一次交易中执行。因此,如果栏目中的任何发言都失败,所有以前的发言将自动撤回。你不需要明确写出任何滚动代码。

然而,有特殊的情况是,人们可以在何时开始/开始/进行回转交易时对谷物控制进行罚款。 Refer to : ,详见。

Answer 3

摘自《邮政》正式文件:

In procedures invoked by the CALL command as well as in anonymous code blocks (DO command), it is possible to end transactions using the commands COMMIT and ROLLBACK. A new transaction is started automatically after a transaction is ended using these commands, so there is no separate START TRANSACTION command. (Note that BEGIN and END have different meanings in PL/pgSQL.)

https://www.postgresql.org/docs/11/plgsql-transactions.html

Answer 4

一项程序在交易中进行,如果存在错误,交易就会得到支持。

例如,你创立了<条码>my_proc(),规定了<条码>5至<条码>。然后,可生成<代码>,按0分列。如下所示错误:

CREATE PROCEDURE my_proc(INOUT value INTEGER) AS $$
BEGIN
SET my.var = 5; -- Here
SELECT 1/value INTO value;
END;
$$ LANGUAGE plpgsql;

首先,请在<代码>2至my.var上查询my_proc(1),然后在<代码>5上打上<编码>。成功如下:

postgres=# SET my.var = 2;
SET
postgres=# CALL my_proc(1);
 my_func
---------
       1
(1 row)
postgres=# SELECT current_setting( my.var );
 current_setting
-----------------
 5
(1 row)

如今,你将<代码>2 至my.var,然后打电话my_proc(0) ,然后在<0/code>误差上打<代码>。

postgres=# SET my.var = 2;
SET
postgres=# CALL my_proc(0);
ERROR:  division by zero
...
postgres=# SELECT current_setting( my.var );
 current_setting
-----------------
 2
(1 row)

Functions

Procedures

Exceptions

友情链接