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POdjango fails to retrieve data using multiple databases
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copied!<p>Im trying to access one database table which is in several databases.</p> <p>I tried using MytableObject.get.using(databasename) first, but it threw error:</p> <pre><code>django.db.utils.DatabaseError: relation "mytable" does not exist </code></pre> <p>So i set out trying to figure out why. as long as i know im not doing anything different than usual :</p> <pre><code>DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'. 'NAME': config.get('databaseDefault', 'DATABASE_NAME'), # Or path to database file if using sqlite3. 'USER': config.get('databaseDefault', 'DATABASE_USER'), # Not used with sqlite3. 'PASSWORD': config.get('databaseDefault', 'DATABASE_PASSWORD'), # Not used with sqlite3. 'HOST': config.get('databaseDefault', 'DATABASE_HOST'), # Set to empty string for localhost. Not used with sqlite3. 'PORT': config.get('databaseDefault', 'DATABASE_PORT'), # Set to empty string for default. Not used with sqlite3. }, 'databaseEe': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'. 'NAME': config.get('databaseEe', 'DATABASE_NAME'), # Or path to database file if using sqlite3. 'USER': config.get('databaseEe', 'DATABASE_USER'), # Not used with sqlite3. 'PASSWORD': config.get('databaseEe', 'DATABASE_PASSWORD'), # Not used with sqlite3. 'HOST': config.get('databaseEe', 'DATABASE_HOST'), # Set to empty string for localhost. Not used with sqlite3. 'PORT': config.get('databaseEe', 'DATABASE_PORT'), # Set to empty string for default. Not used with sqlite3. }, 'databaseLv': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'. 'NAME': config.get('databaseLv', 'DATABASE_NAME'), # Or path to database file if using sqlite3. 'USER': config.get('databaseLv', 'DATABASE_USER'), # Not used with sqlite3. 'PASSWORD': config.get('databaseLv', 'DATABASE_PASSWORD'), # Not used with sqlite3. 'HOST': config.get('databaseLv', 'DATABASE_HOST'), # Set to empty string for localhost. Not used with sqlite3. 'PORT': config.get('databaseLt', 'DATABASE_PORT'), # Set to empty string for default. Not used with sqlite3. }, 'databaseLt': { 'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'. 'NAME': config.get('databaseLt', 'DATABASE_NAME'), # Or path to database file if using sqlite3. 'USER': config.get('databaseLt', 'DATABASE_USER'), # Not used with sqlite3. 'PASSWORD': config.get('databaseLt', 'DATABASE_PASSWORD'), # Not used with sqlite3. 'HOST': config.get('databaseLt', 'DATABASE_HOST'), # Set to empty string for localhost. Not used with sqlite3. 'PORT': config.get('databaseLt', 'DATABASE_PORT'), # Set to empty string for default. Not used with sqlite3. } } </code></pre> <p>And i created some testcode:</p> <pre><code>from django.db import connections cursor = connections[database].cursor() cursor.execute("select tablename from pg_tables WHERE tablename !~* 'pg_*'") print cursor.fetchall() </code></pre> <p>which printed out all my tablenames, "mytable" among them.</p> <p>Then i tried this code :</p> <pre><code>from django.db import connections cursor = connections[database].cursor() cursor.execute("select * from mytable") print cursor.fetchall() </code></pre> <p>which produced error again:</p> <pre><code>django.db.utils.DatabaseError: relation "mytable" does not exist LINE 1: select * from mytable </code></pre> <p>So what am i doing wrong? i can read and write into my default database just fine. I tracked things down to this line:</p> <pre><code>cursor = connections[database].cursor() </code></pre> <p>and found that, if i write actual connection name instead of database, like that:</p> <pre><code>cursor = connections['databaseLv'].cursor() </code></pre> <p>then it works just fine. So how can i do this dynamically?</p> <p>Alan</p>

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