Example:
from tokyo.dystopia import *
idb = IDB()
# if need be, you should call tune/setcache before open,
# ex. with default values:
idb.tune(0, 0, 0, 0)
idb.setcache(0, 0)
# open the database
idb.open("casket.tdi", IDBOWRITER | IDBOCREAT)
# store records
for key, value in [(1, "hop"), (2, "step"), (3, "jump")]:
idb[key] = value
# retrieve one record
print(idb[1])
# traverse records
for key in idb:
print(key, idb[key])
# close the database
idb.close()
Note
For all methods taking either a key argument or a pair (key, value):
Values will always be returned as UTF-8 encoded unicode objects.
On top of that key must always be > 0.
See also
Tune a database.
| Parameters: |
|
|---|
Note
Tuning an open database is an invalid operation.
Set the cache size.
| Parameters: |
|
|---|
Note
Setting the cache size on an open database is an invalid operation.
Set the maximum number of forward matching expansion(?).
| Parameter: | fwmmax – the maximum number of forward matching expansion. |
|---|
Note
Setting this on an open database is an invalid operation.
Open a database.
| Parameters: |
|
|---|
Close the database.
Note
IDBs are closed when garbage-collected.
Copy the database directory.
| Parameter: | path – path to the destination directory. |
|---|
Search a database, return a frozenset of keys whose value match the expressed condition.
| Parameters: |
|
|---|
Conditions can be expressed in two ways:
See also
‘Compound Expression of Search’ at Tokyo Dystopia documentation.
Optimize a database.
Note
Optimizing a read only database is an invalid operation.
The following constants can only be combined with IDBOWRITER :
Create a new database file if it does not exists.
Create a new database file even if one already exists (truncates existing file).
The following constants can be combined with either IDBOREADER or IDBOWRITER :
expr in value #substring test
value.startswith(expr)
value.endswith(expr)
value == expr
expr in value.split()
v.startswith(expr) for v in value.split()
v.endswith(expr) for v in value.split()
| expr | meaning |
|---|---|
| 'expr' | expr in value
|
| 'expr1 expr2' | expr1 in value and expr2 in value
|
| '"expr1 expr2"' | "expr1 expr2" in value
|
| '[[[[expr' | value.startswith(expr)
|
| 'expr]]]]' | value.endswith(expr)
|
| '[[expr]]' | expr in value.split()
|
| '[[expr*]]' | v.startswith(expr) for v in value.split()
|
| '[[*expr]]' | v.endswith(expr) for v in value.split()
|
The expressions above can be combined with || and/or && (|| has a higher order of precedence).
Example:
>>> from tokyo.dystopia import *
>>> presidents = [(1, 'Washington, George'), (2, 'Adams, John'),
... (3, 'Jefferson, Thomas'), (4, 'Madison, James'),
... (5, 'Monroe, James'), (6, 'Adams, John Quincy'),
... (7, 'Jackson, Andrew'), (8, 'Van Buren, Martin'),
... (9, 'Harrison, William Henry'), (10, 'Tyler, John'),
... (11, 'Polk, James Knox'), (12, 'Taylor, Zachary'),
... (13, 'Fillmore, Millard'), (14, 'Pierce, Franklin'),
... (15, 'Buchanan, James'), (16, 'Lincoln, Abraham'),
... (17, 'Johnson, Andrew'), (18, 'Grant, Ulysses S.'),
... (19, 'Hayes, Rutherford Birchard'), (20, 'Garfield, James Abram'),
... (21, 'Arthur, Chester Alan'), (22, 'Cleveland, Grover'),
... (23, 'Harrison, Benjamin'), (24, 'Cleveland, Grover'),
... (25, 'McKinley, William'), (26, 'Roosevelt, Theodore'),
... (27, 'Taft, William Howard'), (28, 'Wilson, Woodrow'),
... (29, 'Harding, Warren Gamaliel'), (30, 'Coolidge, Calvin'),
... (31, 'Hoover, Herbert Clark'), (32, 'Roosevelt, Franklin Delano'),
... (33, 'Truman, Harry'), (34, 'Eisenhower, Dwight David'),
... (35, 'Kennedy, John Fitzgerald'), (36, 'Johnson, Lyndon Baines'),
... (37, 'Nixon, Richard Milhous'), (38, 'Ford, Gerald Rudolph'),
... (39, 'Carter, James Earl Jr.'), (40, 'Reagan, Ronald Wilson'),
... (41, 'Bush, George Herbert Walker'), (42, 'Clinton, William Jefferson'),
... (43, 'Bush, George Walker'), (44, 'Obama, Barack Hussein')]
>>> idb = IDB()
>>> idb.open("presidents.tdi", IDBOWRITER | IDBOCREAT)
>>> for k, v in presidents:
... idb[k] = v
...
>>> idb.search('earl james')
frozenset([39L])
>>> idb.search('"earl james"')
frozenset([])
>>> idb.search('"james earl"')
frozenset([39L])
>>> idb.search('earl || james')
frozenset([4L, 5L, 39L, 11L, 15L, 20L])
>>> idb.search('in]]]]')
frozenset([8L, 44L, 30L, 14L, 23L])
>>> idb.search('in]]]] && am')
frozenset([44L, 23L])
>>> idb.search('in]]]] && [[am]]')
frozenset([])
>>> idb.search('in]]]] && [[am*]]')
frozenset([])
>>> idb.search('in]]]] && [[*am]]')
frozenset([])
>>> idb.search('in]]]] && [[ob*]]')
frozenset([44L])
>>> idb.close()
>>>