Hi Ivan,
yes, when you open a database it gives the driver a chance to do some initialization. It depends on the driver implementation what it actually does. But you may override that behavior in the driver class. This is exactly why you should keep your database instance during the lifetime of your app. Rainer Von: [email protected] [mailto:[email protected]] Im Auftrag von ivan nemeth Gesendet: Montag, 4. August 2014 08:53 An: user Betreff: Re: Best practice to access a DbDatabase? Hi Rainer, thank you for your answer. I've used a static accessor but if I open the database on application start it will open the database for the actual connection. I know that there are no reference to the connection in the database instance, but in case of the SQL Server driver some initialization SQL scripts is executed against the actual connection only and not for other connections (DbDatabaseDriver.attachDatabase). So it's true that there are no explicit reference to a connection from a database instance but there is an implicit binding through these initialization scripts. Thanks, Ivan On Sun, Aug 3, 2014 at 11:12 PM, Rainer Döbele <[email protected]> wrote: Hi Ivan, To answer your question: First you will have to create a class derived from DBDatabase which defines the schema of your database. You then have to open the database when your application starts. This will attach the driver to the database, but I will not block resources like e.g. a connection. In most cases this class will be a singleton. Hence you may e.g. use a static accessor like this: private static MyDatabase myDb; public MyDatabse getDatabase() { if (myDb==null) myDb=new MyDatabase(); return myDb; } Regards Rainer Von: [email protected] [mailto:[email protected]] Im Auftrag von ivan nemeth Gesendet: Freitag, 1. August 2014 16:44 An: user Betreff: Best practice to access a DbDatabase? Hi, a month ago (June 2014) there was a discussion already about connection pooling but I have further questions. I use some kind of connection pooling and Spring's JdbcTemplate, so I have a separate connection for each threads. But how should I access a DbDatabase instance? The db instance is tied to the actual connection, so separate threads can't use the same db instance. 1. Create a new DbDatabase instance for every query/updates/insert. Can it cause any problems, if a lot of instances are created every second? I mean there are static variables which are storing some global states (DbDatabase.databaseMap, DbTable.tableCount etc.) 2. Use some kind of pooling on the DbDatabase. Thanks, Ivan
