Opening a Transactional Environment and Database
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## Opening a Transactional Environment and Database

To enable transactions for your environment, you must initialize the transactional subsystem. Note that doing this also initializes the logging subsystem. In addition, you must initialize the memory pool (in-memory cache). Frequently, but not always, you will also initialize the locking subsystem. For example:

    package db.txn;

    import com.sleepycat.db.DatabaseException;
    import com.sleepycat.db.Environment;
    import com.sleepycat.db.EnvironmentConfig;

    import java.io.File;
    import java.io.FileNotFoundException;

    ...

    Environment myEnv = null;
    try {
        EnvironmentConfig myEnvConfig = new EnvironmentConfig();
        myEnvConfig.setInitializeCache(true);
        myEnvConfig.setInitializeLocking(true);
        myEnvConfig.setInitializeLogging(true);
        myEnvConfig.setTransactional(true);

        myEnv = new Environment(new File("/my/env/home"),
                                  myEnvConfig);

    } catch (DatabaseException de) {
        // Exception handling goes here
    } catch (FileNotFoundException fnfe) {
         // Exception handling goes here
    }

You then can use the `Environment` handle to open your database(s) using `Environment.openDatabase()`. Note that when you do this, you must set `DatabaseConfig.setTransactional()` to `true`. Note that in effect this causes the database open to be transactional protected because it results in auto commit being used for the open (if a transaction is not explicitly used to protect the open). For example:

    package db.txn;

    import com.sleepycat.db.Database;
    import com.sleepycat.db.DatabaseType;
    import com.sleepycat.db.DatabaseConfig;
    import com.sleepycat.db.DatabaseException;
    import com.sleepycat.db.Environment;
    import com.sleepycat.db.EnvironmentConfig;

    import java.io.File;
    import java.io.FileNotFoundException;

    ...

    Database myDatabase = null;
    Environment myEnv = null;
    try {
        EnvironmentConfig myEnvConfig = new EnvironmentConfig();
        myEnvConfig.setInitializeCache(true);
        myEnvConfig.setInitializeLocking(true);
        myEnvConfig.setInitializeLogging(true);
        myEnvConfig.setTransactional(true);

        myEnv = new Environment(new File("/my/env/home"),
                                  myEnvConfig);

        // Open the database.
        DatabaseConfig dbConfig = new DatabaseConfig();
        dbConfig.setTransactional(true);
        dbConfig.setType(DatabaseType.BTREE);
        myDatabase = myEnv.openDatabase(null,               // txn handle
                                        "sampleDatabase",   // db file name
                                        null,             // db name
                                        dbConfig);
    } catch (DatabaseException de) {
        // Exception handling goes here
    } catch (FileNotFoundException fnfe) {
        // Exception handling goes here
    }

### Note

Never close a database that has active transactions. Make sure all transactions are resolved (either committed or aborted) before closing the database.

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