准备好的陈述已经存在 [英] Prepared Statements Already Exists

问题描述

我正在尝试在pg gem中将预备语句用于ruby。这就是我的语句的样子

I am trying to use the prepared statements in ruby with pg gem. This is how my statement looks like

conn.prepare("insert_values", "insert into " + objectName + "(" + headerStr + ") values (" + prep_values + ")")  
conn.exec_prepared("insert_values", arr)

我不断收到错误消息

已准备好的语句insert_values已经存在。

Prepared Statement insert_values already exists.

操作方法我解决这个？谢谢

How Do i Fix this?? Thanks

推荐答案

尝试运行：

conn.exec("DEALLOCATE name_of_prepared_statement")

在您的示例中：

conn.exec("DEALLOCATE insert_values")

简单测试，并且在我的irb中起作用：

Simple test and it is working in my irb:

1.8.7 :001 > require 'rubygems'
  => true
1.8.7 :002 > require 'pg'
  => true
1.8.7 :003 > conn = PGconn.connect(:host => 'localhost', :port => 5912, :user => 'test', :dbname => 'test' )
  => #<PGconn:0x7fe6ac703970> 
1.8.7 :005 > conn.prepare("insert_values", "select * from data where id < $1")
  => #<PGresult:0x7fe6ac6b2e58> 
1.8.7 :006 > conn.prepare("insert_values", "select * from data where id < $1 and id >   $2")
  PGError: ERROR:  prepared statement "insert_values" already exists

  from (irb):6:in 'prepare'
  from (irb):6
1.8.7 :007 > conn.prepare("insert_values", "select * from data where id < $1")
  PGError: ERROR:  prepared statement "insert_values" already exists

  from (irb):7:in 'prepare'
  from (irb):7
1.8.7 :008 > conn.exec("DEALLOCATE insert_values")
  => #<PGresult:0x7fe6ac6738c0> 
1.8.7 :009 > conn.prepare("insert_values", "select * from data where id < $1")
  => #<PGresult:0x7fe6ac665fe0> 
1.8.7 :010 > conn.exec_prepared("insert_values",[200])
  => #<PGresult:0x7fe6ac65d188> 
1.8.7 :011 > conn.exec("DEALLOCATE insert_values")
  => #<PGresult:0x7fe6ac654df8> 
1.8.7 :012 > conn.exec_prepared("insert_values",[200])
  PGError: ERROR:  prepared statement "insert_values" does not exist

  from (irb):12:in 'exec_prepared'
  from (irb):12

这篇关于准备好的陈述已经存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！