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Display all databases names from a given ip, port, username and password using python

I need to show all found databases name.
I have found solutions that obtain information from a known database but in my case I do not know the 'database_name.db'.
someone can help me please!

well, you don't have to :
psql -h localhost -U pguser -c '\l'
this way you will connect to default database (called postgres).
postgres connections need to connect to a database.
output:
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
mytestdb | postgres | UTF8 | en_CA.UTF-8 | en_CA.UTF-8 |
imdb | postgres | UTF8 | en_CA.UTF-8 | en_CA.UTF-8 |
postgres | postgres | UTF8 | en_CA.UTF-8 | en_CA.UTF-8 |
template0 | postgres | UTF8 | en_CA.UTF-8 | en_CA.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_CA.UTF-8 | en_CA.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres

Inner Join in Django

I have two tables
front_employee (Employee model in Django)
+-----------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| order | int(11) | NO | | NULL | |
| name | varchar(100) | YES | | NULL | |
| position | varchar(100) | YES | | NULL | |
| description | longtext | YES | | NULL | |
| employee_img_id | int(11) | NO | MUL | NULL | |
| language_id | int(11) | NO | MUL | NULL | |
+-----------------+--------------+------+-----+---------+----------------+
And front_employeepicture (EmployeePicture in Django)
+-------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| order | int(11) | NO | | NULL | |
| img | varchar(100) | YES | | NULL | |
+-------+--------------+------+-----+---------+----------------+
I would like to perform this query:
SELECT a.id, a.name, b.img
FROM front_employee a
INNER JOIN front_employeepicture b
ON a.employee_img_id = b.id
For now I have
context['employee'] = Employee.objects.all().order_by('order')
And I tried something like
context['employee'] = Employee.objects.select_related('EmployeePicture')
Without result. Any idea?

Django's ORM is really powerful. You actually don't have to do joins like that, ever. When you access the field, the ORM performs the join on the fly, returning the result you want.
first_employee = Employee.objects.all().first()
employee_picture = first_employee.employee_img
And then employee_picture should have the picture of the first employee. It needed to internally do an inner join to figure that out, but Django hides all that for you. (I may have gotten your variable names wrong, sorry).
What select_related does is pre-fetch a relation for every object in a queryset. That means less trips back and forth to the database, which makes your functions faster. But, Django allows you to traverse relationships just by accessing attributes.
Try messing around with this stuff in your django shell. I would add django_extensions to your app (pip install django-extensions, then add django_extensions to your INSTALLED_APPS, then run python manage.py shell_plus). And if not, python manage.py shell works fine, but you have to import your models manually.

save python chinese into MySQL

I already use dict[key]=dict[key].encode('utf-8') in python,
and set mysql default character like this :
--------------------------+--------------------------------------------------------+
| Variable_name | Value |
+--------------------------+--------------------------------------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/local/mysql-5.6.29-osx10.8-x86_64/share/charsets/ |
+--------------------------+--------------------------------------------------------+
but still can't get right chinese, what I get is like 尘的空间 .what's wrong?
I searched some answer and add charset="utf8 self.db=MySQLdb.connect("localhost","root","","QQ",charset="utf8")
get error :
(1366, "Incorrect string value: '\\xE8\\xAF\\x84\\xE8\\xAF\\xAD...' for column 'content' at row 1")

I searched error 1366 ,and find database collation doesn't match the collation I put in MySQL. so I do this:show full columns from table_name; find row that don't use utf-8 encode .then alter table table_name change name name varchar(100) character set utf8 collate utf8_unicode_ci not null default '';
it works.

SqlAlchemy - PostgreSQL - Session connecting with wrong information

I wrote the following code to connect to the database and fill the schema:
db_url = 'postgresql+psycopg2:///bidder:<pass>#localhost:5432/basketball'
Engine = create_engine(db_url, echo=False)
SessionMaker = ORM.sessionmaker(bind=Engine, autoflush=False)
Session = ORM.scoped_session(SessionMaker)
Base.metadata.create_all(Engine)
That last statement, however, raises:
(psycopg2.OperationalError) FATAL: role "fran" does not exist
("fran" is my unix username)
Sqlalchemy is not connecting to the database with the username and password I'm specifying in db_url.
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
------------+----------+----------+-------------+-------------+-----------------------
basketball | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =Tc/postgres +
| | | | | postgres=CTc/postgres+
| | | | | bidder=CTc/postgres
postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
Users table:
rolname
----------
postgres
bidder
(2 rows)

Try removing one of the / from the db_url.
db_url = 'postgresql+psycopg2://bidder:<pass>#localhost:5432/basketball'

How to get the existing postgres databases in a list

I am trying to write a python script to automate the task of creating database using the most recent production dump. I am using psychopg2 for the purpose.
But after the creation of the new database I want to delete the previously used database. My idea is that if I could get the names of databases in a list and sort them, I can easily delete the unwanted database.
So, my question is : How can I get the names of the DBs in a list.
Thanks

You can list all of your DBs with
SELECT d.datname as "Name",
FROM pg_catalog.pg_database d
ORDER BY 1;
You can filter or order it whatever way you like.

psql -E -U postgres -c "\l"
The output of the above command is like
********* QUERY **********
SELECT d.datname as "Name",
pg_catalog.pg_get_userbyid(d.datdba) as "Owner",
pg_catalog.pg_encoding_to_char(d.encoding) as "Encoding",
d.datcollate as "Collate",
d.datctype as "Ctype",
pg_catalog.array_to_string(d.datacl, E'\n') AS "Access privileges"
FROM pg_catalog.pg_database d
ORDER BY 1;
**************************
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
--------------+----------+----------+---------+-------+-----------------------
mickey | postgres | UTF8 | C | C |
mickeylite | postgres | UTF8 | C | C |
postgres | postgres | UTF8 | C | C |
template0 | postgres | UTF8 | C | C | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | C | C | =c/postgres +
| | | | | postgres=CTc/postgres
(5 rows)