List databases command - orientdb

In this link http://orientdb.com/docs/2.2/Tutorial-Run-the-console.html it reads
There are some console commands, such as LIST DATABASES or CREATE
DATABASE, which you can run while only connected to the server
instance. For other commands, however, you must also connect to a
database, before they run without error.
However I tried
orientdb> list databases
Not connected to the Server instance. You've to connect to the Server using server's credentials (look at orientdb-*server-config.xml file)
Is the documentation wrong? Do I need to be connected to a database even to list the list of databases?

I tried your case with my ODB server and I can confirm that you have to be connected to an OrientDB Server instance (but not to a Database) to execute commands like LIST DATABASES. Steps to reproduce:
Connecting to the server:
orientdb> connect remote:localhost root root
Connecting to remote Server instance [remote:localhost] with user 'root'...OK
Executing LIST DATABASES command:
orientdb {server=remote:localhost/}> list databases
Found 3 databases:
* NewDB1 (plocal)
* NewDB2 (plocal)
* GratefulDeadConcerts (plocal)
Maybe in the OrientDB documentation the section
orientdb> LIST DATABASES
Found 1 databases:
* GratefulDeadConcerts (plocal)
could have been reported wrongly.
Hope to have been helpful

Console is just an interface to communicate to the OrientDB server instance like other interfaces viz. Web Editor . So to actually perform commands like CREATE DATABASE and LIST DATABASES , you atleast need to connect to the server (Not to a particular database however). Therefore it is necessary to connect to the server running otherwise console won't know where to CREATE or LIST databases from.

Related

"error: too many connections for database 'postgres'" when trying to connect to any Postgres 13 instance

My team and I are currently experiencing an issue where we can't connect to Cloud SQL's Postgres instance(s) from anything other than the psql cli tool. We get a too many connections for database "postgres" error (in PGAdmin, DBeaver, and our node typeorm/pg backend). It initially happened on our (only) Postgres database instance. After restarting, stopping and starting again, increasing machine CPU/memory proved to do nothing, I deleted the database instance entirely and created a new one from scratch.
However, after a few hours the problem came back. I know that we're not actually having too many connections as I am able to query pg_stat_activity from psql command line and see the following:
Only one of those (postgres username) connections is ours.
My coworker also can't connect at all - not even from psql cli.
If it matters, we are using PostgreSQL 13, europe-west2 (London), single zone availability, db-g1-small instance with 1.7GB memory, 10GB HDD, and we have public IP enabled and the correct IP addresses whitelisted.
I'd really appreciate if anyone has any insights into what's causing this.
EDIT: I further increased the instance size (to no longer be a shared core), and I managed to successfully connect my backend to it. However my psql cli no longer works - it appears that only the first client to connect is allowed to connect after a restart (even if it disconnects, other clients can't connect...).
From the error message, it is clear that the database "postgres" has a custom connection limit (set, for example, by ALTER DATABASE postgres CONNECTION LIMIT 1). And apparently, it is quite small. Why is everyone try to connect to that database anyway? Usually 'postgres' database is reserved for maintenance operations, and you should create other databases for daily use.
You can see the setting with:
select datconnlimit from pg_database where datname='postgres';
I don't know if the low setting is something you did, or maybe Google does it on its own for their cloud offering.
#jjanes had the right idea/mention.
I created another database within the Cloud SQL instance that wasn't named postgres and then it was fine.
It wasn't anything to do with maximum connection settings (as this was within Google Cloud SQL) or not closing connections (as TypeORM/pg does this already).

DB2 CLP connect to remote DB

I downloaded and installed on Windows the following:
IBM DB2 Runtime Client (64-Bit) 10.5
with the aim of connecting to a remote server database.
It installed here:
C:\Program Files\IBM\SQLLIB
But I don't see any DB2 folders in there.
I tried to catalog the remote db like this:
db2 catalog tcpip node testing remote the.server.com server 446
If I then try to connect to it, I get the following:
SQL1031N The database directory cannot be found on the indicated file system.
There is some wizard installed called the 'Default DB2 and IBM Database Client Interface Selection Wizard'. I ran this and it said it would create a default DB2 copy and would be used by default, called DB2COPY1 and it would be installed to C:\Program Files\IBM\SQLLIB.
But I'm nnot sure what this is doing really.
What do I need to do here to connect to the remote DB2??
EDIT:
I have managed to get a bit further based on this article here:
https://www-01.ibm.com/support/docview.wss?uid=swg21008914
my current commands look like:
db2 catalog tcpip node tstnode remote my.server.com server 446
db2 catalog db db1name as mytstdb at node tstnode authentication server
db2 catalog dcs db db1name as A123456DAT
db2 terminate
db2 connect to mytstdb user <username> using <password>
However the connect fails with:
SQL30061N The database alias or database name "A123456DAT " was not
found at the remote node. SQLSTATE=08004
Any ideas?
If you are connecting through port 446, I guess you are trying to connect to DB2 for IBM z or DB2 for IBM i. If yes, you will need at least Db2 Connect.
Regarding error "SQL30061N The database alias or database name "A123456DAT " was not found at the remote node. SQLSTATE=08004" it happens to me when the userid does not have some priviledges on the source system. If it is an IBM i, look at the corresponding spool file. DRDA Connections are attended by jobs called QRWTSRVR. With the IBM i command WRKSPLF SELECT(USERID) (changing USERID by the user trying the DRDA connection) you can see the spool files for jobs related to your connection. Usually spool file messages are very specific on the cause of the failure.
If you are trying to connect to DB2 on z, I don't have experience.

Mongodb not listing collections when connecting remotely from CentOS

Mongo server: Windows 10 (host)
client: CentOS 6.2, a virtual box vm on windows 10 host. This is actually a cloudera quick start vm.
Issue:
mongodb connects to the remote server (from CentOS to Windows) via terminal, lists the databases fine, but 'show collections' just returns blank. That said, the collections are accessible because I can query any collection and the count also gives me the correct results.
On the other hand, I have connected to the same mongo server from IntelliJ and it shows all the collections just fine.
Just curious as to why this is happening.. Any comments?
Side Note: is there a mongodb command to count the number of collections in a database?
Thanks
_Vamsi
Make sure you are using the database you want to show the collections for. You may be using a database that doesn't have any collections.
> use desiredDatabase
> show collections
If the list is still empty, try signing in with an admin user account. The user needs to be able to perform the listCollections action. The dbAdmin role includes the listCollections action.
To get the count you can use the getCollectionNames function which returns an array and you can get the length from that.
> db.getCollectionNames().length

PostgreSQL: One database to multiple user

I have PostgreSQL 9.3 version. I have created database name db1 now I need it to share with other users who all are connected with the LAN's to connect other applications with the same database.
In SQL Server: We can do this by selecting server name with login details.
Question:
Is it possible in PostgreSQL?
If yes, how can do this?
What is the procedure?
You will need to modify pg_hba.conf to allow remote connections to the database. Information about pg_hba.conf can be found here.
After that, you can connect programatically with a connection string, or similar to your image, with a GUI application like pgAdmin.
To connect (remotely or locally) from pgAdmin choose File -> Add Server... and enter the connection information into the dialog box. Here's an example of the window:
Your client computers will also need to have PostgreSQL drivers as well. If you're doing this in Windows, you'll probably be using ODBC. The PostgreSQL ODBC drivers are here. Info on the connection string format can be found here.
Here's an example of what pgAdmin looks like:

JBOSS AS 7 Database internal

1 and i'm connected to intern database java:jboss/datasources/ExampleDS
i want to browse the data like sql in tables etc. in the administration console of jboss
but there is no such option in Administration menu or can someone help me on how to browse data? Or is there some other tool on this?
Database has nothing to do with application server. First you have to find out what database server is datastore ExampleDS using. Then connect to that server. Example: if ExampleDS uses Mysql on 192.168.1.1:3306 you have to use some Mysql client (Mysql workbanch) to connect to that server. There you can see actual tables.