PHP：PGSQL驱动程序和AutoCommit？ [英] PHP: PGSQL driver and AutoCommit?

问题描述

我在项目中使用pg_connect和pg_query。
但是我真的不确定是否使用AutoCommit模式进行pg_connect吗？

I use pg_connect, and pg_query in a project. But I'm really not sure that is pg_connect using AutoCommit mode or not?

这是一个重要的问题，因为我需要在事务下编写一些块，如果服务器将忽略其中一个语句，则数据库将不一致...

It is important question, because I need to write some block under transaction, and if one of the statements would be ignored by the server, the database would be inconsistent...

还有一个有趣的问题，在执行后pg_query会提交吗？

Also interesting question that do pg_query a commit after execution?

例如：

pg_query('begin; update table1...; update table2...; commit');

与

pg_query('begin;');
pg_query('update table1...;');
pg_query('update table2...;');
pg_query('commit');

并且是

pg_query('begin; update table1...; update table2...; commit');

在自动提交模式下工作，那么开始和提交仍然有效吗？

working in AutoCommit mode, so begin and commit is nevertheless?

感谢您的帮助：
dd

Thanks for your help: dd

推荐答案

首先，PostgreSQL中没有AutoCommit模式和PHP API的pg_ *函数不会尝试模拟一个。

First, there is no AutoCommit mode in PostgreSQL and the pg_* functions of the PHP API do not try to emulate one.

pg_query的 doc 说

pg_query's doc says

将多个语句传递给函数时，它们就是
自动执行为一项交易，除非查询字符串中包含显式
BEGIN / COMMIT命令

When multiple statements are passed to the function, they are automatically executed as one transaction, unless there are explicit BEGIN/COMMIT commands included in the query string

pg_query（ UPDATE1 ..; UPDATE2 ...）在一个事务中执行，并且对数据产生全有或全无的影响。

So it guarantees that pg_query("UPDATE1 ..; UPDATE2...") executes in one transaction and has an all-or-nothing effect on the data.

序列

pg_query("BEGIN");
pg_query("UPDATE1...");
pg_query("UPDATE2..");
pg_query("COMMIT");

等效于 pg_query（ UPDATE1 ..; UPDATE2 ... ）关于数据完整性（半成品状态不会发生）。

is equivalent to pg_query("UPDATE1 ..; UPDATE2...") with regard to data integrity (half-finished state cannot happen).

关于注释除非有明确的BEGIN / COMMIT。 ..，仅当它们不在整个SQL语句链的开头和结尾时才有意义。
即 pg_query（ BEGIN; update1; update2; COMMIT;）; 等效于 pg_query（ update1; update2; ），但（显然）不等同于 pg_query（ update1; COMMIT; update2;）

As for the note "unless there are explicit BEGIN/COMMIT...", it is relevant only if these are not at the beginning and end of the entire chain of SQL statements. That is, pg_query("BEGIN; update1; update2; COMMIT;"); is equivalent to pg_query("update1; update2;") but (obviously) not equivalent to pg_query("update1; COMMIT; update2;")

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