DBSequence

Sequences provide an arbitrary number of persistent objects that return an increasing or decreasing sequence of integers. Opening a sequence handle associates it with a record in a database. The handle can maintain a cache of values from the database so that a database update is not needed as the application allocates a value.

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DBSequence Methods

DBSequence(db, flags=0)
Constructor. More info...
open(key, txn=None, flags=0)
Opens the sequence represented by the key. More info...
close(flags=0)
Close a DBSequence handle. More info...
initial_value(value)
Set the initial value for a sequence. This call is only effective when the sequence is being created. More info...
get(delta=1, txn=None, flags=0)
Returns the next available element in the sequence and changes the sequence value by delta. More info...
get_dbp()
Returns the DB object associated to the DBSequence. More info...
get_key()
Returns the key for the sequence. More info...
remove(txn=None, flags=0)
Removes the sequence from the database. This method should not be called if there are other open handles on this sequence. More info...
get_cachesize()
Returns the current cache size. More info...
set_cachesize(size)
Configure the number of elements cached by a sequence handle. More info...
get_flags()
Returns the current flags. More info...
set_flags(flags)
Configure a sequence. More info...
stat(flags=0)

Returns a dictionary of sequence statistics with the following keys:

wait The number of times a thread of control was forced to wait on the handle mutex.
nowait The number of times that a thread of control was able to obtain handle mutex without waiting.
current The current value of the sequence in the database.
value The current cached value of the sequence.
last_value The last cached value of the sequence.
min The minimum permitted value of the sequence.
max The maximum permitted value of the sequence.
cache_size The number of values that will be cached in this handle.
flags The flags value for the sequence.

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get_range()
Returns a tuple representing the range of values in the sequence. More info...
set_range((min, max))
Configure a sequence range. More info...