createPartition

createPartition(): Integer64;

The createPartition method of the DbFile class creates a new empty database file partition and returns the partition identifier.

You can make a number of related createPartition operations atomic, by containing them in the same database transaction, as shown in the following example.

// execute just before midnight at end of current period
beginTransaction;
    Order.getDbFile.createPartition;
    OrderItem.getDbFile.createPartition;
// execute just after midnight at start of next period
commitTransaction;

When the createPartition operation is invoked on a partitioned database file, any transactions that attempt to create new instances are blocked until the transaction that invoked the createPartition operation commits or aborts.

An exception is raised if the database file is locked for reorganization or if the file is not partitioned.

The following restrictions apply to the use of the createPartition method.

• Partitions can be created only within a transaction

• No other partition creation operation can be in progress

• Persistent objects cannot be created or updated in the transaction that creates a partition

• Persistent objects cannot be created in a partitioned file by any user while a new partition for that file is being created