I'm building a Java app that needs to co-exist with a VBasic one. Both consume a single Access database (.mdb)
As sometimes the VB app writes the DB I'd need to programmatically re-read from disk the mdb. Is there a way to do this? is this Jackcess responsibility or Ucanaccess?
I'm using UcanAccess with Spring and Mybatis.
UCanAccess always reloads the data when another process updates the db file
Related
I am using AbstractRoutingDataSource to store data sources which are stored in database during spring boot application startup.
System can switch to correct database during program running.
When end users manual change database connection information from UI (like change password every 6 months), then sysem need to reload data sources information.
According to testing, even sytem reset target data sources, the old jdbc connection is used.
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.
We have multiple oracle schema which we want to import in to somekind of inmemory db so that when we run our integration test we can use that db and run our tests faster.
Is there anyway we this can be achieved using something like HSQL db. We are using spring framework and it does support inmemory db.
Any link to some resource would be highly appreciated.
Try force full database caching mode, if you're using 12.1.0.2. It's not exactly the same as a full in-memory database, but it should be closer.
alter database force full database caching;
In-memory database performance is over-rated anyway. Oracle's "old-fashioned" asynchronous IO and caching often work just fine. For example, in this question, accessing a temporary table (which is stored on disk) runs faster than an equivalent solution using in-memory data structures. And I've seen a small Oracle database handle petabytes of IO with the "boring" old buffer cache.
Or when you say "run our tests faster", are you referring to a more agile database; one that can be controlled by an individual, instead of the typical monolithic Oracle database installed on a server? I see that issue a lot, and there's no technical reason why Oracle can't be installed on your desktop. But that can be a tough cultural battle.
Yes, you can use HSQLDB for the purpose of unit testing - see this post for more information on how to integrate with Spring.
Also, see this list as a good starting point for different usages of HSQLDB.
I'm using WebSphere application server and I've database to write my MI data. Now requirement is to write some where even when my database is down or table space exceeds it's limit.
I thought of writing it to a file when db is down but I read some where that it is not suggestible when using WebSphere server as it causes problem in a clustered environment.
Can any one suggest better way to handle this requirement?
Solution is simple.
You should use shared file storage.
It must be available for each cluster member.
I have the following issue:
Two instances of an application on two different systems should share a small database.
The main problem is that both systems can only exchange data through a network-folder.
I don't have the possibilty to setup a database-server somewhere.
Is it possible to place a H2 database on the network-folder and let both instances connect to the database (also concurrently)?
I could connect with both instances to the db using the embedded mode if I disable the file-locking, right?
The instances can perfom either READ or INSERT operations on the db. Do I risk data corruptions using multiple concurrent embedded connections?
As the documentation says; ( http://h2database.com/html/features.html#auto_mixed_mode
)
Multiple processes can access the same database without having to start the server manually. To do that, append ;AUTO_SERVER=TRUE to the database URL. You can use the same database URL independent of whether the database is already open or not. This feature doesn't work with in-memory databases.
// Application 1:
DriverManager.getConnection("jdbc:h2:/data/test;AUTO_SERVER=TRUE");
// Application 2:
DriverManager.getConnection("jdbc:h2:/data/test;AUTO_SERVER=TRUE");
From H2 documentation:
It is also possible to open the database without file locking; in this
case it is up to the application to protect the database files.
Failing to do so will result in a corrupted database.
I think that if your application use always the same configuration (shared file database on network folder), you need to create an application layer that manages concurrency