Answer a question

I'm going to guess that the answer is "no" based on the below error message (and this Google result), but is there anyway to perform a cross-database query using PostgreSQL?

databaseA=# select * from databaseB.public.someTableName;
ERROR:  cross-database references are not implemented:
 "databaseB.public.someTableName"

I'm working with some data that is partitioned across two databases although data is really shared between the two (userid columns in one database come from the users table in the other database). I have no idea why these are two separate databases instead of schema, but c'est la vie...

Answers

Note: As the original asker implied, if you are setting up two databases on the same machine you probably want to make two schemas instead - in that case you don't need anything special to query across them.

postgres_fdw

Use postgres_fdw (foreign data wrapper) to connect to tables in any Postgres database - local or remote.

Note that there are foreign data wrappers for other popular data sources. At this time, only postgres_fdw and file_fdw are part of the official Postgres distribution.

For Postgres versions before 9.3

Versions this old are no longer supported, but if you need to do this in a pre-2013 Postgres installation, there is a function called dblink.

I've never used it, but it is maintained and distributed with the rest of PostgreSQL. If you're using the version of PostgreSQL that came with your Linux distro, you might need to install a package called postgresql-contrib.

# mssql # postgresql
Logo
PostgreSQL

PostgreSQL社区为您提供最前沿的新闻资讯和知识内容

更多推荐

PostgreSQL 计数查询效率,物化视图 [重复]

问题:PostgreSQL 计数查询效率,物化视图 [重复] 可能重复: PostgreSQL 计数查询优化 使用 PostgreSQL 9.2,我们试图弄清楚是否有一种方法可以跟踪查询的结果数量,并以有效的方式返回该数字。这个查询应该每秒执行几次(可能几十到几百甚至几千次)。我们现在的查询看起来像这样,但我们想知道这是否效率低下: -- Get # of rows that do not hav

avatar PostgreSQL

多对多中的唯一性

问题:多对多中的唯一性 我无法弄清楚谷歌的哪些术语,所以帮助标记这个问题或只是以相关问题的方式向我指出会有所帮助。 我相信我有一个典型的多对多关系: CREATE TABLE groups ( id integer PRIMARY KEY); CREATE TABLE elements ( id integer PRIMARY KEY); CREATE TABLE groups_elements

avatar PostgreSQL

Django 与 postgresql - manage.py syncdb 返回错误

问题:Django 与 postgresql - manage.py syncdb 返回错误 我从 Django 开始。我设置了一些使用 SQLite 工作的站点,但是在将 DB 引擎更改为 postgresql manage.py syncdb 后返回错误。我已经用谷歌搜索了 2 天,但对我仍然没有任何作用。Postgres 用户 'joe' 具有超级用户权限和本地 'joe ' 数据库存在。

avatar PostgreSQL