Develop Reference

Connect Metabase to Sql Server

I installed Java on my Windows 10 machine and downloaded Metabase.jar, and ran it.
Now I could access metabase at localhost:3000
But I'm unable to setup my SQL Server Database as Data reference.
I'm either getting:
Couldn't connect to the database. Please check the connection details.
or
Timed out after 5000 milliseconds.
Anyone who has done Metabase - SQL Server connection successfully?

Currently, as of Metabase version 0.30.x the answer depends on if you can use a user configured directly on SQL Server or not:
The easier option to setup is with a user configured directly on SQL Server. Then config is just Name: (anything), Host: (full name), Database Name, Username, Password as you would expect. (I believe you should NOT fill in the Windows domain).
On Windows only you can also use native integrated authentication with sqljdbc_auth.dll, just specify integratedSecurity=true connection property (and optionally authenticationScheme=NativeAuthentication). I found if I dropped the x64 sqljdbc_auth.dll in my <java path>\jre\bin folder it was picked up. Metabase config as in the screenshot below, apart from dropping authenticationScheme=JavaKerberos
The cross platform authenticationScheme=JavaKerberos option to use Windows Authentication with a domain user is still doable, but harder. It's these steps:
Create a krb.conf and verify login works with <Java path>\bin\kinit.exe [user]. Here's a template edited to match the Metabase database setup in the screenshot below.
Start the Metabase.jar file with parameters to load the krb.conf. It works for me with java -Djava.security.krb5.conf=c:/<path>/kerberos/krb.conf -jar metabase.jar.
Now configure the database settings in Metabase according to the screenshot below
Moment of truth! ...
Optional: Still not working? Maybe your SQL Server isn't configured for Kerberos? Maybe you need SPN setup? Maybe you need to specify a java.security.auth.login.config (I have not experienced any of that myself, only thing I can offer is you scroll to the bottom of this post and dive in then edit your question with where you got to and what config you have)
Metabase SQL Server setup using Kerberos:
For background, current (August 2018) very long :| sum up with lots of links of how to connect to SQL Server is here in a Metabase discussion topic Note: In v0.30.0 an issue with dynamic port handling (particularly for people using named instances) was fixed.
Related: A neat StackOverflow answer on Kerberos on a Mac

If you are connecting to a "Named Instance" ({SERVER_NAME}/{INSTANCE_NAME}) instead of "Default Instance" ({SERVER_NAME}), your server may be configured to use Dynamic Port.
A quick dirty fix is you can find the current port with below scripts and then use it on Metabase connection parameters. But this port most probably will change when service restart occurs.
SELECT DISTINCT
local_tcp_port
FROM sys.dm_exec_connections
WHERE local_tcp_port IS NOT NULL
or
USE master
GO
Xp_readerrorlog
(look for "Server is listening on ..." line)
A Cleaner way is setting port for your instance by "SQL Server Configuration Manager" - "SQL Server Network Configuration" - "TCP/IP" - Right Click properties - "TCP Dynamic Ports" (There should be 0 and it should be deleted) and "TCP Port" (New default port should be set here). And also "SQL Server Browser" service should run. A more detailed explanation is here

How to connect opc kepware server through a Java program, without the username and the password?

I am trying to connect opc kepware server through a Java program, I want to know what jar files can be used to connect to KepwareserverEx.V5 and what is the code without the use of password and username.
I have referenced http://www.opcconnect.com/uakit.php, and https://github.com/digitalpetri/ua-server-sdk, but it doesn't have anything that doesn't connect without a username and a pawssword. I have a program in vb that connects to kepware using Interop.OPCAutomation.dll file and uses the code:
ConnectedOPCServer = New OPCAutomation.OPCServer
ConnectedOPCServer.Connect("Kepware.KEPServerEX.V5", "")
ConnectedGroup = ConnectedOPCServer.OPCGroups.Add("MPM Group")
ConnectedGroup.UpdateRate = 1000
ConnectedGroup.IsSubscribed = True
ConnectedGroup.IsActive = True
I want to write Java code in a similar way. Searched through the internet to see various examples, but none have the above connection without a username and password not being specified.

First of all, I assume that you have created an "anonymous" and "SecurityPolicy.None" endpoint on KepServerEX.
You refer to digitalpetri's old and server SDK. The new project is called "Milo". I can recommend you take a look at the Milo project's client SDK examples using this link. There is an application of anonymous identity and none security policy.
In terms of jar, you can either build your client-sdk (see example here) or directly download the client-sdk jar from Maven Central.
NB Milo is considered to be in incubation. That is to say, it is not mature yet. Be careful using it in production systems.

Yes that's right. The security policy is none on the KepwareServerEX. I made some permission changes on the server where Kepware exists, so that my localhost computer would be able to talk to the Kepware server host. Provided credentials for my localhost, and able to connect.

Use Neo4jGraph.open() or GraphFactory.open() to access remote Neo4j database in Java

I'm using the Tinkerpop's GraphFactory.open(Configuration configuration) Java command to access a Neo4j database.
A working minimum example is:
Configuration configuration = new BaseConfiguration();
configuration.addProperty("gremlin.graph", "org.apache.tinkerpop.gremlin.neo4j.structure.Neo4jGraph");
configuration.addProperty("gremlin.neo4j.directory", "tmp/neo4j");
GraphFactory.open(configuration);
However, I want to connect to a remote Neo4j database instead.
So I need something like
configuration.addProperty("gremlin.neo4j.directory", "ip:port");
which results in an exception:
java.lang.RuntimeException: java.io.IOException: Unable to create directory path [C:\Users\backend\192.168.56.102:7474] for Neo4j store.
Seems like Neo4j tries to access the ip:port like a file path...
Thanks in advance for your help.

As you've found, that approach won't work. Neo4jGraph is designed to work as embedded and thus requires either a file system location for the database files or it can become a node in a HA cluster which is described here.
Your other choice is to use a third-party implementation that uses the Bolt protocol, neo4j-gremlin-bolt. That should do what you want.

Thanks to stephen mallette, I found a solution.
From Neo4j 3.0, the Bolt protocol is enabled by default.
So I used neo4j-gremlin-bolt to connect to my Neo4j remote database via Java as follows:
Driver driver = GraphDatabase.driver("bolt://<IP>", AuthTokens.basic("user", "pass"));
Graph graph = new Neo4JGraph(driver, vertexIdProvider, edgeIdProvider));
Read about the ID providers at the link provided.

What should it look like when one of the host failed for zookeeper when building zk connections in java

I have the code like the following:
ZooKeeperInstance inst = new ZooKeeperInstance(this.instance, this.zkServers);
Connector this.conn = inst.getConnector(this.user, new PasswordToken(this.password));
(this.zkServers is a list of zk host separated by comma;
ZookeeperInstance is from the package of "org.apache.accumulo.core.client")
When one of the host from this.zkServers is died, but the other two host still work, these two lines just failed to connect. Does anyone know how to explain this? Thanks.
Does that mean that accumulo connection needs all the hosts in zookeeper to keep alive?

I have also noticed this behavior. You should be able to connect if you remove the dead server from your zkServers connection string.
It is unfortunate that Accumulo does not fail over to the next server, perhaps someone should file a bug report.

Error connecting to Oracle database using JDBC [duplicate]

I am new to Oracle, and am trying to run a simple example code with Java, but am getting this error when executing the code.. I am able to start up the listener via CMD and am also able to run SQL Plus. Can anyone give me a hand and tell me what I might be doing wrong?
Update:
I am using JDBC.
Database is local, and I actually had it working but it stopped working just today. I'm not really sure why though. Would you mind giving me some procedures to follow by since I don't know much.

Either:
The database isn't running
You got the URL wrong
There is a firewall in the way.
(This strange error message is produced by Oracle's JDBC driver when it can't connect to the database server. 'Network adapter' appears to refer to some component of their code, which isn't very useful. Real network adapters (NICs) don't establish connections at all: TCP protocol stacks do that. It would have been a lot more useful if they had just let the original ConnectException be thrown, or at least used its error message and let it appear in the stack trace.)

I had the same problem, and this is how I fixed it.
I was using the wrong port for my connection.
private final String DB_URL = "jdbc:oracle:thin:#localhost:1521:orcll"; // 1521 my wrong port
go to your localhost
(my localhost address) : https://localhost:1158/em
login
user name
password
connect as --> normal
Below 'General' click on LISTENER_localhost
look at you port number
Net Address (ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1522))
Connect to port 1522
Edit you connection
change port 1521 to 1522.
done

Another thing you might want to check that the listener.ora file matches the way you are trying to connect to the DB. If you were connecting via a localhost reference and your listener.ora file got changed from:
HOST = localhost
to
HOST = 192.168.XX.XX
then this can cause the error that you had unless you update your hosts file to accommodate for this. Someone might have made this change to allow for remote connections to the DB from other machines.

I figured out that in my case, my database was in different subnet than the subnet from where i was trying to access the db.

I had this error when i renamed the pc in the windows-properties. The pc-name must be updated in the listener.ora-file

Most probably you have listener configured wrongly, the hostname you specify in connection string must be the same as in the listener.
First check the Firewall and network related issues.
Check if Oracle Listener service is available and running. If not you may use Oracle Net Configuration Assistant tool to add and register new listener.
If the above steps are ok then you need to configure Oracle Listener appropriately. You may use Oracle Net Manager tool or edit “%ORACLE_HOME%\network\admin\listener.ora” file manually.
There are 2 options that need to be considered carefully:
Listening Locations associated with the Listener – Hostname(IP) and Port in Listening Location must exactly match the ones used in the connection string.
For example, if you use 192.168.74.139 as target hostname, then there must be Listening Location registered with the same IP address.
Also make sure the you use the same SID as indicated in Database Service associated with the Listener.
https://adhoctuts.com/fix-oracle-io-error-the-network-adapter-could-not-establish-the-connection-error/

IO Error: The Network Adapter could not establish the connection (CONNECTION_ID=iKQM6lBbSLiArrYuDqud8A==)
if you are facing this issue
1- make sure you have downloaded oracle databases like oracle 11g,19c, 21c, or any latest databases.
2- search for services in your computer or type win+r then services.mis then search for oracleservice you will find orcl or xe or any other sid like oracleserviceorcl;
after that you can test your connection using sql developer, sql plus or cmd

To resolve the Network Adapter Error I had to remove the - in the name of the computer name.

In my case, I needed to specify a viahost and viauser. Worth trying if you're in a complex system. :)

For me the basic oracle only was not installed. Please ensure you have oracle installed and then try checking host and port.

I was having issues with this as well. I was using the jdbc connection string to connect to the database. The hostname was incorrectly configured in the string. I am using Mac, and the same string was being used on Windows machines without an issue. On my connection string, I had to make sure that I had the full url with the appending "organizationname.com" to the end of the hostname.
Hope this helps.

Just try to re-create connection. In my situation one of jdbc connection stopped working for no reason. From console sqlplus was working ok.
It took me 2 hours to realize that If i create the same connection - it works.