Postgres DB无法通过RJDBC连接到R. [英] Postgres DB can't connect to R with RJDBC

问题描述

我一直在尝试通过R查询来自PostgreSQL数据库的数据。我尝试用一​​些不同的软件包对猫进行换肤（ RODBC，RJDBC，DBI，RPostgres 等），但我似乎一直在收到驱动程序错误。奇怪的是，我从来没有使用相同的驱动程序/ URL和设置从SQLWorkbench / J连接到Postgres。

I've been trying to query data from a PostgreSQL DB via R. I've tried skinning the cat with a few different packages (RODBC, RJDBC, DBI, RPostgres, etc), but I seem to keep getting driver errors. Oddly, I never have trouble using the same drivers/URL's and settings to connect to Postgres from SQLWorkbench/J.

我尝试使用 postgresql -9.2-1002.jdbc4.jar 和 postgresql-9.3-1100.jdbc41.jar ，以及通用 R中的PostgreSQL驱动程序。两个jar文件分别是（i）我一直使用SQLWorkbench / J的驱动程序和（ii）相同驱动程序的略微更新版本。然而，当我尝试使用它时......

I've tried using postgresql-9.2-1002.jdbc4.jar and postgresql-9.3-1100.jdbc41.jar, as well as the generic "PostgreSQL" driver in R. The two jar files are the (i) the driver I use all the time with SQLWorkbench/J and (ii) the slightly newer version of that same driver, respectively. Yet, when I try to use it...

drv_custom <- JDBC(driverClass = "org.postgresql.Driver", classPath="/Users/xxxx/postgresql-9.3-1100.jdbc41.jar")

I得到错误：

Error in .jfindClass(as.character(driverClass)[1]) : class not found

好的，接下来我尝试使用通用驱动程序：

OK, so next I try it with the generic driver:

drv_generic <- dbDriver("PostgreSQL")

奇怪的是，它不希望我输入用户名：

and strangely, it doesn't want me to enter a username:

>con <- dbConnect(drv=drv_generic, "jdbc:postgresql://xxx.xxxxx.com", port=xxxx,     uid="xxxx", password="xxxx")
>Error in postgresqlNewConnection(drv, ...) : unused argument (uid = "xxxx")

所以我尝试没有用户/ uid：

so I try it without user/uid:

con< - dbConnect（drv_generic，jdbc：postgresql：//padb-01.jiwiredev.com：5439，password =paraccel）

con <- dbConnect(drv_generic, "jdbc:postgresql://padb-01.jiwiredev.com:5439", password="paraccel")

并收到错误....

Error in postgresqlNewConnection(drv, ...) : 
RS-DBI driver: (could not connect jdbc:postgresql://padb-01.xxx.com:5439@local on dbname "jdbc:postgresql://xxxx.xxxx.com:5439")

显然语法错了？

然后我回过头来尝试自定义驱动程序（前面提到的.jar文件之一）但没有指定driverClass。

Then I circle back to trying the "custom" driver (either one of the .jar files from earlier) but without the driverClass specified.

drv_custom1< - JDBC（classPath =/ Users / xxxx / postgresql-9.2-1002.jdbc4.jar）

drv_custom1 <- JDBC( classPath="/Users/xxxx/postgresql-9.2-1002.jdbc4.jar")

con< - dbConnect（drv = drv_custom1，jdbc：postgresql：//xxx.xxx.com，port = 5439，uid =paraccel，pwd =paraccel）

con <- dbConnect(drv=drv_custom1, "jdbc:postgresql://xxx.xxx.com", port=5439, uid="paraccel", pwd="paraccel")

并收到此错误：

Error in .jcall(drv@jdrv, "Ljava/sql/Connection;", "connect", as.character(url)[1],  : 
RcallMethod: attempt to call a method of a NULL object.

我再次尝试了一下，但语法略有改动：

I tried it again with a slight alteration to the syntax:

con <- dbConnect(drv=drv_custom1, url="jdbc:postgresql://xxxx.xxxx.com", port=xxxx, uid="xxxx", pwd="xxxxx",dsn="xxxx")

并得到了同样的错误。我尝试了其他一些其他的变化/方法也是如此。我想我的困惑之一来自于这样一个事实，即文档在DBI之类的程序包之间以及像RJDBC之类的程序之间以非常零碎的方式处理，因此当我查看诸如之类的文档？dbConnect 我需要指定的许多选项甚至没有提及，我一直在根据与这些包/错误相关的各种Google搜索结果进行工作。

and got the same error. I tried a number of other variations/approaches as well. I think part of my confusion comes from the fact that the documentation is handled in a very piecemeal way between packages like DBI and those that build upon it like RJDBC, so that when I look at documentation such as ?dbConnect many of the options I need to specify are not even mentioned, and I've been working based off of miscellaneous Google search results related to these packages/errors.

我找到的一个帖子建议尝试

One thread I found suggested trying

.jaddClassPath( "xxxxx/postgresql-9.2-1002.jdbc4.jar" )

首先，但这似乎没有帮助。

first, but that didn't seem to help.

我也尝试过使用

x <- PostgreSQL(max.con = 16, fetch.default.rec = 500, force.reload = FALSE)

无效，我尝试用RODBC作为驱动程序。

to no avail and I experimented with RODBC as the driver.

更新：

我尝试使用较旧版本的驱动程序（jdbc3而不是jdbc4），重启R并且分离所有你不必要的套餐。

I tried using an older version of the driver (jdbc3 instead of jdbc4), restarting R, and detaching all unnecessary packages.

我能够加载驱动程序

> drv_custom <- JDBC(driverClass = "org.postgresql.Driver", classPath="/xxxxx/xxxxx/postgresql-9.3-1100.jdbc3.jar")

但我仍然无法连接......

but I still can't connect...

> con <- dbConnect(drv=drv_custom, "jdbc:postgresql://xxxxx.xxxxx.com", port=5439, uid="xxxxx", pwd="xxxxx")
Error in .verify.JDBC.result(jc, "Unable to connect JDBC to ", url) : 
Unable to connect JDBC to jdbc:postgresql://xxxxx.xxxx.com

推荐答案

这对我有用：

library(RJDBC)
drv <- JDBC("org.postgresql.Driver","C:/R/postgresql-9.4.1211.jar")
con <- dbConnect(drv, url="jdbc:postgresql://host:port/dbname", user="<user name>", password="<password>")

诀窍是包括 port 和 dbname 在 url 中。出于某种原因， jdbc：postgresql 似乎不喜欢从 dbConnect 参数中读取这些信息。

The trick was to include port and dbname in the url. For some reason, jdbc:postgresql does not seem to like reading those information from the dbConnect parameters.

• 如果你不确定 dbname 是什么，它可能是 postgres 。


• 如果您不确定端口是什么，它可能是 5432 。

• If you are not sure what the dbname is, it is perhaps postgres.
• If you are not sure what the port is, it is perhaps 5432.

所以典型的电话会是这样的：

So a typical call would look like:

con <- dbConnect(drv, url="jdbc:postgresql://10.10.10.10:5432/postgres", user="<user name>", password="<password>")

您可以获得 jar 来自 https://jdbc.postgresql.org/ 的文件

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