GAE doesn't support JDBC but is there a way to use it anyway? Is there a way to connect to an external Oracle db to store structured information using the RDBMS pattern? Is the a wrapper or a runtime lib that makes it possible to connect to an external RDBMS using JDBC?
I don't want to use GAE's in-house MySQL cloud hack.
You cannot open sockets on GAE, that's why you cannot open a JDBC connection for any outside RDBMS.
BTW, today they launched a trusted tester program for sockets on GAE:
http://googleappengine.blogspot.com.br/2012/09/app-engine-172-released.html
But I believe this is not the case they are trying to address
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In one of the use cases in my application there is a requirement to publish neo4j transaction data to oracle database in real time. I did google on it, but couldn't find a tool or plug-in which can help. Everywhere on internet talks about rdbms to neo4j sync. So I am planning to do this by manually invoking jdbc commands.
Can you please suggest something?
Had to write my own jdbc code.
I have only used db links to get access to remote db so far. Now I have to find a way to use JDBC to connect to remote db and get data. Can someone guide me what all things would I need to ask the remote db admin in order to setup a jdbc connection, and once I have the connection, how do I query the database using java stored procedure, just like I am querying it over remote db right now with db link?
You've described a fairly complicated problem, but haven't given any information about your database or operating system. Are you connecting to a SQL Server database? MySQL? Are you running on Linux? Windows?
First, you'll need a driver. That's going to depend on the database, operating system and versions thereof that you're using. For example, here is the Microsoft ODBC Driver for SQL Server (Oops, looks like it's currently unavailable.)
Second, you need to set up Oracle Heterogenous Services. That's fairly complicated and not something I can answer here. You might start with the Database Gateway for ODBC User's Guide.
Oracle does have gateways for various other databases, but they're licensed additionally from the database itself.
I have to load two Derby instances that reference same data Derby file in a remote repository.
Is it possible? How can I achieve this? Would you give detailed information?
Two different connections in the same Derby app is ok because Derby uses Java synchronization features to coordinate their access to the db.
Two different apps cannot use Java synchronization because that only works inside a single Jvm class loader so instead Derby locks the db and only allows one app at a time to access the db.
That is the benefit of the Derby network server because many apps can access the db simultaneously via the network server.
There is a hybrid mode by which one embedded app can also serve as the network server for other apps but it is complex and usually not the best choice.
Update: You can find more information about embedded servers in these docs: http://db.apache.org/derby/docs/10.11/adminguide/cadminov825149.html and http://db.apache.org/derby/docs/10.11/adminguide/radminembeddedserverex.html
or by searching the Internet for "Derby embedded server".
I'm from MySQL background and am new to Oracle. I want to know
What is meant by Oracle Client?
What is its use?
What is its equivalent in MySQL ?
Thanks
What is meant by Oracle Client?
and
What is its use?
In this context, a client is a class library (DLL) that allows you to connect remotely to the underlying database of an application. A client, always within the same context, can also be called a .NET Data Provider.
You may have multiple data providers based on the underlying database engine with which you're working.
There was System.Data.OracleClient (deprecated), provided by Microsoft.
There is Oracle.Data.Client, which is actually the best ever built Oracle Client, or Oracle .NET Data Provider. You may also download the latest Oracle 11g Data Provider for .NET.
So, when accessing the Oracle underlying database, make sure your work with this provider, proper for your version of Oracle, and start doing ADO.NET with your favorite database! =P
There are also some other tools that you can work with that will ease your data access code pain, such as Enterprise Library or NHibernate, both are frameworks to basically accessing databases.
Enterprise Library can do even more then that!
And NHibernate is an ORM (Object/Relation Mapping) tool that can work just very fine with Oracle.
Remember though, always use Oracle.Data.Client namespace in the Oracle.DataAccess.dll assembly.
What is its equivalent in MySQL ?
As the equivalence for MySQL, I guess it would be MySQL Connector/NET.
It is the Oracle binaries installed that allow communication with the Oracle database. It can be using SQL*Plus, JDBC (type II or IV) or OCI (Oracle Call Interface).
Its a piece of software that allows a remote computer to talk to Oracle. If you were to write a piece of software that communicated with the database, you would use the Oracle Client to facilitate that communication
I have tried SQLite in Java, but the speed is slow due to the JDBC driver. Then I tried HSQLDB and thought the speed is good, but I cannot find a good management tool for HSQLDB such as phpMyAdmin for MySQL or SQLite Manager for SQLite.
I'd like to use the manager tool to prepare the test data for unit tests, or use the manager tool to navigate the data after doing some small experiments.
Is there any good tool?
Here are a couple other suggestions you might checkout:
Squirrel SQL http://squirrel-sql.sourceforge.net/
Execute Query http://executequery.org/
Razor SQL (paid) http://www.razorsql.com/
Razor has the best feature set, but is paid. The others are good at different things and worth checking into.
This would only have meaning if you are running in HSQLDB server mode. If you are running in memory or file mode, then you either can't access the DB from another process or doing so would lock it.
In Server mode you could use any universal client. JDBC driver is the hsqldb.jar itself.
Actually HSQL brings its own management tool (which is not super). See http://hsqldb.org/doc/guide/apf.html
I've used Squirrel SQL. It's a universal client for any JDBC database.
See: http://squirrel-sql.sourceforge.net/