使用ruby pg gem准备的INSERT语句的示例 [英] Example of a prepared INSERT statement using ruby pg gem

问题描述

做了一些谷歌搜索大约半天，我找不到使用pg gem（PostgreSQL红宝石gem）准备的INSERT语句的任何样本。

Did some googling for about half a day and I can't find any sample of a prepared INSERT statement using the pg gem (postgresql ruby gem).

I尝试过此操作（在查看了gem文档之后）：

I tried this (after looking at the gem docs):

def test2
    conn = PG.connect( dbname: 'db1' )
    conn.prepare("statement1", 'INSERT INTO table1 (id, name, profile) VALUES (?, ?, ?)')
end

但出现以下错误：

pgtest.rb:19:in `prepare': ERROR:  syntax error at or near "," (PG::Error)
LINE 1: INSERT INTO table1 (id, name, profile) VALUES (?, ?, ?)
                                                        ^
from pgtest.rb:19:in `test2'
from pgtest.rb:25:in `<main>'

推荐答案

pg 宝石希望您使用编号的占位符（ $ 1 ， $ 2 ？）：

The pg gem wants you to use numbered placeholders ($1, $2, ...) rather than positional placeholders (?):

conn = PG.connect(:dbname => 'db1')
conn.prepare('statement1', 'insert into table1 (id, name, profile) values ($1, $2, $3)')
conn.exec_prepared('statement1', [ 11, 'J.R. "Bob" Dobbs', 'Too much is always better than not enough.' ])

精细手册的意思是：

-（PGresult）prepare（stmt_name，sql [，param_types]）

[... ]

PostgreSQL绑定参数在SQL查询中表示为$ 1，$ 1，$ 2等。

- (PGresult) prepare(stmt_name, sql[, param_types ])
[...]
PostgreSQL bind parameters are represented as $1, $1, $2, etc., inside the SQL query.

再次针对 exec_prepared ：

PostgreSQL绑定参数在SQL查询中表示为$ 1，$ 1，$ 2等。 params数组的第0个元素绑定到$ 1，第一个元素绑定到$ 2，依此类推。

PostgreSQL bind parameters are represented as $1, $1, $2, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc.

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