def connect(self):
"""Connect to the database.
Connects to the database only if the store has not already and provided
that the store has a valid model.
The default implementation of connect() is usually sufficient provided
that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect:' \
' No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = True
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
self.augmentDatabaseArgs(args, pool=True)
try:
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
except TypeError:
if 'database' in args:
del args['database']
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
else:
raise
def connect(self):
"""Connect to the database.
Connects to the database only if the store has not already and provided
that the store has a valid model.
The default implementation of connect() is usually sufficient provided
that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect:' \
' No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = True
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
self.augmentDatabaseArgs(args, pool=True)
try:
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
except TypeError:
if 'database' in args:
del args['database']
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
else:
raise
def testDbPool(self):
pool = DBPool(sqlite3, 10, database=':memory:')
for _count in range(15):
con = pool.connection()
cursor = con.cursor()
cursor.execute("select 1 union select 2 union select 3 order by 1")
rows = cursor.fetchall()
self.assertEqual(rows, [(1, ), (2, ), (3, )])
con.close()
def Test(iterations=15):
try:
dbapi_name = 'pgdb'
dbapi = __import__(dbapi_name)
pool = DBPool(dbapi, 10, database='template1')
for i in range(iterations):
db = pool.connection()
cursor = db.cursor()
cursor.execute("select datname from pg_database order by 1")
r = cursor.fetchmany(5)
r = ', '.join(map(lambda s: s[0], r))
print i, r
db.close()
except Exception:
import traceback
traceback.print_exc()
print 'You need the pgdb adapter and a test database for this example.'
def connect(self):
"""
Connects to the database only if the store has not already and
provided that the store has a valid model.
The default implementation of connect() is usually sufficient
provided that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect: No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = 1
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
if not args.get('db'):
args['db'] = self._model.sqlDatabaseName()
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
class SQLObjectStore(ObjectStore):
"""
TO DO:
* _sqlEcho should be accessible via a config file setting as stdout, stderr or a filename.
For details on DB API 2.0, including the thread safety levels see:
http://www.python.org/topics/database/DatabaseAPI-2.0.html
"""
## Init ##
def __init__(self, **kwargs):
# @@ 2001-02-12 ce: We probably need a dictionary before kwargs for subclasses to pass to us in case they override __init__() and end up collecting kwargs themselves
ObjectStore.__init__(self)
self._dbArgs = kwargs
self._connected = 0
self._sqlEcho = None
self._sqlCount = 0
self._pool = None # an optional DBPool
def modelWasSet(self):
"""
Performs additional set up of the store after the model is set,
normally via setModel() or readModelFileNamed(). This includes
checking that threading conditions are valid, and connecting to
the database.
"""
ObjectStore.modelWasSet(self)
# Check thread safety
self._threadSafety = self.threadSafety()
if self._threaded and self._threadSafety == 0:
raise SQLObjectStoreThreadingError, 'Threaded is 1, but the DB API threadsafety is 0.'
# Cache some settings
self._markDeletes = self.setting('DeleteBehavior', 'delete') == 'mark'
# Set up SQL echo
self.setUpSQLEcho()
# Set up attrs for caching
for klass in self.model().allKlassesInOrder():
klass._getMethods = {}
klass._setMethods = {}
for attr in klass.allDataAttrs():
attr._sqlColumnName = None
# Connect
self.connect()
def setUpSQLEcho(self):
"""
Sets up the SQL echoing/logging for the store according to the
setting 'SQLLog'. See the User's Guide for more info. Invoked by
modelWasSet().
"""
setting = self.setting('SQLLog', None)
if setting == None or setting == {}:
self._sqlEcho = None
else:
filename = setting['File']
if filename == None:
self._sqlEcho = None
elif filename == 'stdout':
self._sqlEcho = sys.stdout
elif filename == 'stderr':
self._sqlEcho = sys.stderr
else:
mode = setting.get('Mode', 'write')
assert mode in ['write', 'append']
mode = mode[0]
self._sqlEcho = open(filename, mode)
## Connecting to the db ##
def isConnected(self):
return self._connected
def connect(self):
"""
Connects to the database only if the store has not already and
provided that the store has a valid model.
The default implementation of connect() is usually sufficient
provided that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect: No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = 1
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
if not args.get('db'):
args['db'] = self._model.sqlDatabaseName()
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
def newConnection(self):
"""
Returns a DB API 2.0 connection. This is a utility method
invoked by connect(). Subclasses should implement this, making
use of self._dbArgs (a dictionary specifying host, username,
etc.) as well as self._model.sqlDatabaseName().
Subclass responsibility.
"""
raise AbstractError, self.__class__
def readKlassIds(self):
"""
Reads the klass ids from the SQL database. Invoked by connect().
"""
conn, cur = self.executeSQL('select id, name from _MKClassIds;')
klassesById = {}
for (id, name) in cur.fetchall():
assert id, "Id must be a non-zero int. id=%r, name=%r" % (id, name)
klass = self._model.klass(name)
klassesById[id] = klass
klass.setId(id)
self._klassesById = klassesById
## Changes ##
def commitInserts(self, allThreads=0):
unknownSerialNums = []
for object in self._newObjects.items(allThreads):
self._insertObject(object, unknownSerialNums)
for unknownInfo in unknownSerialNums:
stmt = unknownInfo.updateStmt()
self.executeSQL(stmt)
self._newObjects.clear(allThreads)
def _insertObject(self, object, unknownSerialNums):
# New objects not in the persistent store have serial numbers less than 1
if object.serialNum() > 0:
try:
rep = repr(object)
except:
rep = '(repr exception)'
assert object.serialNum() < 1, 'object=%s' % rep
# SQL insert
sql = object.sqlInsertStmt(unknownSerialNums)
conn, cur = self.executeSQL(sql)
# Get new id/serial num
idNum = self.retrieveLastInsertId(conn, cur)
# Update object
object.setSerialNum(idNum)
object.setKey(ObjectKey().initFromObject(object))
object.setChanged(0)
# Update our object pool
self._objects[object.key()] = object
def retrieveLastInsertId(self, conn, cur):
""" Returns the id (typically a 32-bit int) of the last INSERT operation by this connection. Used by commitInserts() to get the correct serial number for the last inserted object.
Subclass responsibility. """
raise AbstractError, self.__class__
def commitUpdates(self, allThreads=0):
for object in self._changedObjects.values(allThreads):
sql = object.sqlUpdateStmt()
self.executeSQL(sql)
object.setChanged(0)
self._changedObjects.clear(allThreads)
def commitDeletions(self, allThreads=0):
for object in self._deletedObjects.items(allThreads):
sql = object.sqlDeleteStmt()
self.executeSQL(sql)
self._deletedObjects.clear(allThreads)
## Fetching ##
def fetchObject(self, aClass, serialNum, default=NoDefault):
""" Fetches a single object of a specific class and serial number. TheClass can be a Klass object (from the MiddleKit object model), the name of the class (e.g., a string) or a Python class.
Raises an exception if theClass parameter is invalid, or the object cannot be located.
"""
klass = self._klassForClass(aClass)
objects = self.fetchObjectsOfClass(klass,
serialNum=serialNum,
isDeep=0)
count = len(objects)
if count == 0:
if default is NoDefault:
raise UnknownObjectError, 'aClass = %r, serialNum = %r' % (
aClass, serialNum)
else:
return default
else:
assert count == 1
return objects[0]
def fetchObjectsOfClass(self,
aClass,
clauses='',
isDeep=1,
refreshAttrs=1,
serialNum=None):
"""
Fetches a list of objects of a specific class. The list may be empty if no objects are found.
aClass can be a Klass object (from the MiddleKit object model), the name of the class (e.g., a string) or a Python class.
The clauses argument can be any SQL clauses such as 'where x<5 order by x'. Obviously, these could be specific to your SQL database, thereby making your code non-portable. Use your best judgement.
serialNum can be a specific serial number if you are looking for a specific object. If serialNum is provided, it overrides the clauses.
You should label all arguments other than aClass:
objs = store.fetchObjectsOfClass('Foo', clauses='where x<5')
The reason for labeling is that this method is likely to undergo improvements in the future which could include additional arguments. No guarantees are made about the order of the arguments except that aClass will always be the first.
Raises an exception if aClass parameter is invalid.
"""
klass = self._klassForClass(aClass)
# Fetch objects of subclasses first, because the code below will be modifying clauses and serialNum
deepObjs = []
if isDeep:
for subklass in klass.subklasses():
deepObjs.extend(
self.fetchObjectsOfClass(subklass, clauses, isDeep,
refreshAttrs, serialNum))
# Now get objects of this exact class
objs = []
if not klass.isAbstract():
fetchSQLStart = klass.fetchSQLStart()
className = klass.name()
if serialNum is not None:
clauses = 'where %s=%d' % (klass.sqlIdName(), serialNum)
if self._markDeletes:
clauses = self.addDeletedToClauses(clauses)
conn, cur = self.executeSQL(fetchSQLStart + clauses + ';')
for row in cur.fetchall():
serialNum = row[0]
key = ObjectKey().initFromClassNameAndSerialNum(
className, serialNum)
obj = self._objects.get(key, None)
if obj is None:
pyClass = klass.pyClass()
obj = pyClass()
assert isinstance(
obj, MiddleObject
), 'Not a MiddleObject. obj = %r, type = %r, MiddleObject = %r' % (
obj, type(obj), MiddleObject)
obj.readStoreData(self, row)
obj.setKey(key)
self._objects[key] = obj
else:
# Existing object
if refreshAttrs:
obj.readStoreData(self, row)
objs.append(obj)
objs.extend(deepObjs)
return objs
## Klasses ##
def klassForId(self, id):
return self._klassesById[id]
## Self utility for SQL, connections, cursors, etc. ##
def executeSQL(self, sql, connection=None):
"""
Executes the given SQL, connecting to the database for the first
time if necessary. This method will also log the SQL to
self._sqlEcho, if it is not None. Returns the connection and
cursor used and relies on connectionAndCursor() to obtain these.
Note that you can pass in a connection to force a particular one
to be used.
"""
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
self._sqlCount += 1
if self._sqlEcho:
timestamp = funcs.timestamp()['pretty']
self._sqlEcho.write('SQL %04i. %s %s\n' %
(self._sqlCount, timestamp, sql))
self._sqlEcho.flush()
# if self._sqlCount in (2, 3, 4):
# import traceback as tb
# tb.print_stack()
conn, cur = self.connectionAndCursor(connection)
self._executeSQL(cur, sql.strip())
return conn, cur
def _executeSQL(self, cur, sql):
"""
Invokes execute on the cursor with the given SQL. This is a
hook for subclasses that wish to influence this event. Invoked
by executeSQL().
"""
cur.execute(sql)
def setSQLEcho(self, file):
""" Sets a file to echo sql statements to, as sent through executeSQL(). None can be passed to turn echo off. """
self._sqlEcho = file
def connectionAndCursor(self, connection=None):
"""
Returns the connection and cursor needed for executing SQL,
taking into account factors such as setting('Threaded') and the
threadsafety level of the DB API module. You can pass in a
connection to force a particular one to be used. Uses
newConnection() and connect().
"""
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
if connection:
conn = connection
elif self._threaded:
if self._pool:
conn = self._pool.getConnection()
elif self._threadSafety is 1:
conn = self.newConnection()
else: # safety = 2, 3
if not self._connected:
self.connect()
conn = self._connection
else:
# Non-threaded
if not self._connected:
self.connect()
conn = self._connection
cursor = conn.cursor()
return conn, cursor
def newConnection(self):
"""
Subclasses must override to return a newly created database connection.
"""
raise AbstractError, self.__class__
def threadSafety(self):
return self.dbapiModule().threadsafety
def addDeletedToClauses(self, clauses):
"""
Modify the given set of clauses so that it filters out records with non-NULL deleted field
"""
clauses = clauses.strip()
if clauses.lower().startswith('where'):
orderByIndex = clauses.lower().find('order by')
if orderByIndex == -1:
where = clauses[5:]
orderBy = ''
else:
where = clauses[5:orderByIndex]
orderBy = clauses[orderByIndex:]
return 'where deleted is null and (%s) %s' % (where, orderBy)
else:
return 'where deleted is null %s' % clauses
## Obj refs ##
def fetchObjRef(self, objRef):
"""
Given an unarchived object reference, this method returns the
actual object for it (or None if the reference is NULL or
dangling). While this method assumes that obj refs are stored
as 64-bit numbers containing the class id and object serial
number, subclasses are certainly able to override that
assumption by overriding this method.
"""
assert type(objRef) is LongType, 'type=%r, objRef=%r' % (type(objRef),
objRef)
if objRef == 0:
return None
else:
klassId, serialNum = objRefSplit(objRef)
if klassId == 0 or serialNum == 0:
# invalid! we don't use 0 serial numbers
return self.objRefZeroSerialNum(objRef)
klass = self.klassForId(klassId)
# Check if we already have this in memory first
key = ObjectKey()
key.initFromClassNameAndSerialNum(klass.name(), serialNum)
obj = self._objects.get(key, None)
if obj:
return obj
clauses = 'where %s=%d' % (klass.sqlIdName(), serialNum)
objs = self.fetchObjectsOfClass(klass, clauses, isDeep=0)
if len(objs) == 1:
return objs[0]
elif len(objs) > 1:
raise ValueError, 'Multiple objects.' # @@ 2000-11-22 ce: expand the msg with more information
else:
return self.objRefDangles(objRef)
def objRefZeroSerialNum(self, objRef):
""" Invoked by fetchObjRef() if either the class or object serial number is 0. """
raise ObjRefZeroSerialNumError, objRefSplit(objRef)
def objRefDangles(self, objRef):
""" Invoked by fetchObjRef() if there is no possible target object for the given objRef, e.g., a dangling reference. This method invokes self.warning() and includes the objRef as decimal, hexadecimal and class:obj numbers. """
raise ObjRefDanglesError, objRefSplit(objRef)
## Debugging ##
def dumpTables(self, out=None):
if out is None:
out = sys.stdout
out.write('DUMPING TABLES\n')
out.write('BEGIN\n')
for klass in self.model().klasses().values():
out.write(klass.name() + '\n')
self.executeSQL('select * from %s;' % klass.name())
out.write(str(self._cursor.fetchall()))
out.write('\n')
out.write('END\n')
def dumpKlassIds(self, out=None):
if out is None:
out = sys.stdout
wr = out.write('DUMPING KLASS IDs\n')
for klass in self.model().klasses().values():
out.write('%25s %2i\n' % (klass.name(), klass.id()))
out.write('\n')
class SQLObjectStore(ObjectStore):
"""The MiddleKit SQL Object Store.
TO DO:
* _sqlEcho should be accessible via a config file setting
as stdout, stderr or a filename.
For details on DB API 2.0, including the thread safety levels see:
http://www.python.org/topics/database/DatabaseAPI-2.0.html
"""
## Init ##
def __init__(self, **kwargs):
# @@ 2001-02-12 ce: We probably need a dictionary before kwargs
# for subclasses to pass to us in case they override __init__()
# and end up collecting kwargs themselves
ObjectStore.__init__(self)
self._dbArgs = kwargs
self._connected = False
self._commited = False
self._sqlEcho = None
self._sqlCount = 0
self._pool = None # an optional DBPool
def modelWasSet(self):
"""Perform additional set up of the store after the model is set.
Performs additional set up of the store after the model is set, normally
via setModel() or readModelFileNamed(). This includes checking that
threading conditions are valid, and connecting to the database.
"""
ObjectStore.modelWasSet(self)
# Check thread safety
self._threadSafety = self.threadSafety()
if self._threaded and self._threadSafety == 0:
raise SQLObjectStoreThreadingError('Threaded is True,'
' but the DB API threadsafety is 0.')
# Cache some settings
self._markDeletes = self.setting('DeleteBehavior', 'delete') == 'mark'
# Set up SQL echo
self.setUpSQLEcho()
# Set up attrs for caching
for klass in self.model().allKlassesInOrder():
klass._getMethods = {}
klass._setMethods = {}
for attr in klass.allDataAttrs():
attr._sqlColumnName = None
attr._sqlColumnNames = None
# use dbargs from settings file as defaults
# (args passed to __init__ take precedence)
args = self._dbArgs
self._dbArgs = self.setting('DatabaseArgs', {})
self._dbArgs.update(args)
# print 'dbArgs = %s' % self._dbArgs
# Connect
self.connect()
def setUpSQLEcho(self):
"""Set up the SQL echoing/logging for the store.
The logging is set up according to the setting 'SQLLog'.
See the User's Guide for more info. Invoked by modelWasSet().
"""
setting = self.setting('SQLLog', None)
if setting is None or setting == {}:
self._sqlEcho = None
else:
filename = setting['File']
if filename is None:
self._sqlEcho = None
elif filename == 'stdout':
self._sqlEcho = sys.stdout
elif filename == 'stderr':
self._sqlEcho = sys.stderr
else:
mode = setting.get('Mode', 'write')
assert mode in ['write', 'append']
mode = mode[0]
self._sqlEcho = open(filename, mode)
## Connecting to the db ##
def isConnected(self):
return self._connected
def connect(self):
"""Connect to the database.
Connects to the database only if the store has not already and provided
that the store has a valid model.
The default implementation of connect() is usually sufficient provided
that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect:' \
' No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = True
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
self.augmentDatabaseArgs(args, pool=True)
try:
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
except TypeError:
if 'database' in args:
del args['database']
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
else:
raise
def augmentDatabaseArgs(self, args, pool=False):
# give subclasses the opportunity to add or change
# database arguments
pass
def newConnection(self):
"""Return a DB API 2.0 connection.
This is a utility method invoked by connect(). Subclasses should
implement this, making use of self._dbArgs (a dictionary specifying
host, username, etc.) as well as self._model.sqlDatabaseName().
Subclass responsibility.
"""
raise AbstractError(self.__class__)
def readKlassIds(self):
"""Read the klass ids from the SQL database. Invoked by connect()."""
conn, cur = self.executeSQL('select id, name from _MKClassIds;')
try:
klassesById = {}
for klassId, name in cur.fetchall():
assert klassId, 'Id must be a non-zero int.' \
' id=%r, name=%r' % (klassId, name)
try:
klass = self._model.klass(name)
except KeyError:
filename = self._model.filename()
msg = ('%s The database has a class id for %r in the'
' _MKClassIds table, but no such class exists in'
' the model %s. The model and the db are not in sync.'
% (name, name, filename))
raise KeyError(msg)
klassesById[klassId] = klass
klass.setId(klassId)
finally:
self.doneWithConnection(conn)
self._klassesById = klassesById
## Changes ##
def commitInserts(self, allThreads=False):
unknownSerialNums = []
# @@ ... sort here for dependency order
for obj in self._newObjects.items(allThreads):
self._insertObject(obj, unknownSerialNums)
conn = None
try:
for unknownInfo in unknownSerialNums:
stmt = unknownInfo.updateStmt()
conn, cur = self.executeSQL(stmt, conn)
finally:
self.doneWithConnection(conn)
self._newObjects.clear(allThreads)
def _insertObject(self, obj, unknownSerialNums):
# New objects not in the persistent store have serial numbers less than 1
if obj.serialNum() > 0:
try:
rep = repr(obj)
except Exception:
rep = '(repr exception)'
assert obj.serialNum() < 1, 'obj=%s' % rep
# try to get the next ID (if database supports this)
idNum = self.retrieveNextInsertId(obj.klass())
# SQL insert
sql = obj.sqlInsertStmt(unknownSerialNums, idNum)
conn, cur = self.executeSQL(sql)
try:
# Get new id/serial num
if idNum is None:
idNum = self.retrieveLastInsertId(conn, cur)
# Update object
obj.setSerialNum(idNum)
obj.setKey(ObjectKey().initFromObject(obj))
obj.setChanged(False)
# Update our object pool
self._objects[obj.key()] = obj
finally:
self.doneWithConnection(conn)
def retrieveNextInsertId(self, klass):
"""Return the id for the next new object of this class.
Databases which cannot determine the id until the object has been
added return None, signifying that retrieveLastInsertId
should be called to get the id after the insert has been made.
"""
return None
def retrieveLastInsertId(self, conn, cur):
"""Return the id of the last INSERT operation by this connection.
This id is typically a 32-bit int. Used by commitInserts() to get
the correct serial number for the last inserted object.
"""
return cur.lastrowid
def commitUpdates(self, allThreads=False):
conn = None
try:
for obj in self._changedObjects.values(allThreads):
sql = obj.sqlUpdateStmt()
conn, cur = self.executeSQL(sql, conn)
obj.setChanged(False)
finally:
self.doneWithConnection(conn)
self._changedObjects.clear(allThreads)
def commitDeletions(self, allThreads=False):
conn = None
try:
for obj in self._deletedObjects.items(allThreads):
sql = obj.sqlDeleteStmt()
conn, cur = self.executeSQL(sql, conn)
conn.commit()
finally:
self.doneWithConnection(conn)
self._deletedObjects.clear(allThreads)
## Fetching ##
def fetchObject(self, aClass, serialNum, default=NoDefault):
"""Fetch a single object of a specific class and serial number.
aClass can be a Klass object (from the MiddleKit object model),
the name of the class (e.g., a string) or a Python class.
Raises an exception if aClass parameter is invalid, or the object
cannot be located.
"""
klass = self._klassForClass(aClass)
objects = self.fetchObjectsOfClass(klass, serialNum=serialNum, isDeep=False)
count = len(objects)
if count == 0:
if default is NoDefault:
raise UnknownObjectError('aClass = %r, serialNum = %r'
% (aClass, serialNum))
else:
return default
else:
assert count == 1
return objects[0]
def fetchObjectsOfClass(self, aClass,
clauses='', isDeep=True, refreshAttrs=True, serialNum=None):
"""Fetch a list of objects of a specific class.
The list may be empty if no objects are found.
aClass can be a Klass object (from the MiddleKit object model),
the name of the class (e.g., a string) or a Python class.
The clauses argument can be any SQL clauses such as 'where x<5 order by x'.
Obviously, these could be specific to your SQL database, thereby making
your code non-portable. Use your best judgement.
serialNum can be a specific serial number if you are looking for
a specific object. If serialNum is provided, it overrides the clauses.
You should label all arguments other than aClass:
objs = store.fetchObjectsOfClass('Foo', clauses='where x<5')
The reason for labeling is that this method is likely to undergo
improvements in the future which could include additional arguments.
No guarantees are made about the order of the arguments except that
aClass will always be the first.
Raises an exception if aClass parameter is invalid.
"""
klass = self._klassForClass(aClass)
# Fetch objects of subclasses first, because the code below
# will be modifying clauses and serialNum
deepObjs = []
if isDeep:
for subklass in klass.subklasses():
deepObjs.extend(self.fetchObjectsOfClass(
subklass, clauses, isDeep, refreshAttrs, serialNum))
# Now get objects of this exact class
objs = []
if not klass.isAbstract():
fetchSQLStart = klass.fetchSQLStart()
className = klass.name()
if serialNum is not None:
serialNum = int(serialNum) # make sure it's a valid int
clauses = 'where %s=%d' % (klass.sqlSerialColumnName(), serialNum)
if self._markDeletes:
clauses = self.addDeletedToClauses(clauses)
conn, cur = self.executeSQL(fetchSQLStart + clauses + ';')
try:
for row in cur.fetchall():
serialNum = row[0]
key = ObjectKey().initFromClassNameAndSerialNum(className, serialNum)
obj = self._objects.get(key)
if obj is None:
pyClass = klass.pyClass()
obj = pyClass()
assert isinstance(obj, MiddleObject), (
'Not a MiddleObject. obj = %r, type = %r, MiddleObject = %r'
% (obj, type(obj), MiddleObject))
obj.readStoreData(self, row)
obj.setKey(key)
self._objects[key] = obj
else:
# Existing object
if refreshAttrs:
obj.readStoreData(self, row)
objs.append(obj)
finally:
self.doneWithConnection(conn)
objs.extend(deepObjs)
return objs
def refreshObject(self, obj):
assert obj.store() is self
return self.fetchObject(obj.klass(), obj.serialNum())
## Klasses ##
def klassForId(self, id):
return self._klassesById[id]
## Self utility for SQL, connections, cursors, etc. ##
def executeSQL(self, sql, connection=None, commit=False):
"""Execute the given SQL.
This will connect to the database for the first time if necessary.
This method will also log the SQL to self._sqlEcho, if it is not None.
Returns the connection and cursor used and relies on connectionAndCursor()
to obtain these. Note that you can pass in a connection to force a
particular one to be used and a flag to commit immediately.
"""
sql = str(sql) # Excel-based models yield Unicode strings which some db modules don't like
sql = sql.strip()
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
self._sqlCount += 1
if self._sqlEcho:
timestamp = funcs.timestamp()['pretty']
self._sqlEcho.write('SQL %04i. %s %s\n' % (self._sqlCount, timestamp, sql))
self._sqlEcho.flush()
conn, cur = self.connectionAndCursor(connection)
self._executeSQL(cur, sql)
if commit:
conn.commit()
return conn, cur
def _executeSQL(self, cur, sql):
"""Invoke execute on the cursor with the given SQL.
This is a hook for subclasses that wish to influence this event.
Invoked by executeSQL().
"""
cur.execute(sql)
def executeSQLTransaction(self, transaction, connection=None, commit=True):
"""Execute the given sequence of SQL statements and commit as transaction."""
if isinstance(transaction, basestring):
transaction = [transaction]
try:
for sql in transaction:
if connection:
self.executeSQL(sql, connection)
else:
connection, cur = self.executeSQL(sql)
except Exception:
if connection and commit:
connection.rollback()
raise
if transaction and connection and commit:
try:
connection.commit()
except Exception:
connection.rollback()
raise
return connection
def executeSQLScript(self, sql, connection=None):
"""Execute the given SQL script.
This uses the nonstandard executescript() method as provided
by the PySQLite adapter.
"""
sql = str(sql).strip()
if not connection:
connection = self.newConnection()
if not hasattr(connection, 'executescript'):
raise AttributeError(
'Script execution not supported by database adapter.')
return connection.executescript(sql)
def setSQLEcho(self, file):
"""Set a file to echo sql statements to, as sent through executeSQL().
None can be passed to turn echo off.
"""
self._sqlEcho = file
def connectionAndCursor(self, connection=None):
"""Return the connection and cursor needed for executing SQL.
Takes into account factors such as setting('Threaded') and the
threadsafety level of the DB API module. You can pass in a connection to
force a particular one to be used. Uses newConnection() and connect().
"""
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
if connection:
conn = connection
elif self._threaded:
if self._pool:
conn = self._pool.connection()
elif self._threadSafety == 1:
conn = self.newConnection()
else: # safety = 2, 3
if not self._connected:
self.connect()
conn = self._connection
else:
# Non-threaded
if not self._connected:
self.connect()
conn = self._connection
cursor = conn.cursor()
return conn, cursor
def threadSafety(self):
"""Return the threadsafety of the DB API module."""
return self.dbapiModule().threadsafety
def dbapiVersion(self):
"""Return the version of the DB API module."""
module = self.dbapiModule()
return '%s %s' % (module.__name__, module.version)
def dbVersion(self):
"""Return the database version.
Subclass responsibility.
"""
raise AbstractError(self.__class__)
def addDeletedToClauses(self, clauses):
"""Modify the given set of clauses so that it filters out records with non-NULL deleted field."""
clauses = clauses.strip()
if clauses.lower().startswith('where'):
where = clauses[5:]
orderByIndex = where.lower().find('order by')
if orderByIndex < 0:
orderBy = ''
else:
where, orderBy = where[:orderByIndex], where[orderByIndex:]
return 'where deleted is null and (%s) %s' % (where, orderBy)
else:
return 'where deleted is null %s' % clauses
## Obj refs ##
def fetchObjRef(self, objRef):
"""Fetch referenced object.
Given an unarchived object reference, this method returns the actual
object for it (or None if the reference is NULL or dangling). While
this method assumes that obj refs are stored as 64-bit numbers containing
the class id and object serial number, subclasses are certainly able to
override that assumption by overriding this method.
"""
assert isinstance(objRef, long), 'type=%r, objRef=%r' % (type(objRef), objRef)
if objRef == 0:
return None
else:
klassId, serialNum = objRefSplit(objRef)
if klassId == 0 or serialNum == 0:
# invalid! we don't use 0 serial numbers
return self.objRefZeroSerialNum(objRef)
klass = self.klassForId(klassId)
# Check if we already have this in memory first
key = ObjectKey()
key.initFromClassNameAndSerialNum(klass.name(), serialNum)
obj = self._objects.get(key)
if obj:
return obj
clauses = 'where %s=%d' % (klass.sqlSerialColumnName(), serialNum)
objs = self.fetchObjectsOfClass(klass, clauses, isDeep=False)
if len(objs) == 1:
return objs[0]
elif len(objs) > 1:
# @@ 2000-11-22 ce: expand the msg with more information
raise ValueError('Multiple objects.')
else:
return self.objRefDangles(objRef)
def objRefInMem(self, objRef):
"""Return referenced object in memory.
Returns the object corresponding to the given objref if and only if it
has been loaded into memory. If the object has never been fetched from
the database, None is returned.
"""
assert isinstance(objRef, long), 'type=%r, objRef=%r' % (type(objRef), objRef)
if objRef == 0:
return 0
else:
klassId, serialNum = objRefSplit(objRef)
if klassId == 0 or serialNum == 0:
# invalid! we don't use 0 serial numbers
return self.objRefZeroSerialNum(objRef)
klass = self.klassForId(klassId)
# return whether we have this object in memory
key = ObjectKey()
key.initFromClassNameAndSerialNum(klass.name(), serialNum)
return self._objects.get(key)
def objRefZeroSerialNum(self, objRef):
"""Raise serial number zero error.
Invoked by fetchObjRef() if either the class or the object serial
number is zero.
"""
raise ObjRefZeroSerialNumError(objRefSplit(objRef))
def objRefDangles(self, objRef):
"""Raise dangling reference error.
Invoked by fetchObjRef() if there is no possible target object
for the given objRef.
E.g., this can happen for a dangling reference. This method invokes
self.warning() and includes the objRef as decimal, hexadecimal
and class:obj numbers.
"""
raise ObjRefDanglesError(objRefSplit(objRef))
## Special Cases ##
def filterDateTimeDelta(self, dtd):
"""Adapt DateTimeDeltas.
Some databases have no TIME type and therefore will not return
DateTimeDeltas. This utility method is overridden by subclasses
as appropriate and invoked by the test suite.
"""
return dtd
def sqlNowCall(self):
"""Get current DateTime."""
return 'CURRENT_TIMESTAMP'
## Self util ##
def doneWithConnection(self, conn):
"""Invoked by self when a connection is no longer needed.
The default behavior is to commit and close the connection.
"""
if conn is not None:
# Starting with 1.2.0, MySQLdb disables autocommit by default,
# as required by the DB-API standard (PEP-249). If you are using
# InnoDB tables or some other type of transactional table type,
# you'll need to do connection.commit() before closing the connection,
# or else none of your changes will be written to the database.
try:
conn.commit()
except Exception:
pass
conn.close()
## Debugging ##
def dumpTables(self, out=None):
if out is None:
out = sys.stdout
out.write('DUMPING TABLES\n')
out.write('BEGIN\n')
conn = None
try:
for klass in self.model().klasses().values():
out.write(klass.name() + '\n')
conn, cur = self.executeSQL('select * from %s;'
% klass.name(), conn)
out.write(str(self._cursor.fetchall()))
out.write('\n')
finally:
self.doneWithConnection(conn)
out.write('END\n')
def dumpKlassIds(self, out=None):
if out is None:
out = sys.stdout
wr = out.write('DUMPING KLASS IDs\n')
for klass in self.model().klasses().values():
out.write('%25s %2i\n' % (klass.name(), klass.id()))
out.write('\n')
def dumpObjectStore(self, out=None, progress=False):
if out is None:
out = sys.stdout
for klass in self.model().klasses().values():
if progress:
sys.stderr.write(".")
out.write('%s objects\n' % (klass.name()))
attrs = [attr for attr in klass.allAttrs() if attr.hasSQLColumn()]
colNames = [attr.name() for attr in attrs]
colNames.insert(0, klass.sqlSerialColumnName())
out.write(CSVJoiner.joinCSVFields(colNames) + "\n")
# write out a line for each object in this class
objlist = self.fetchObjectsOfClass(klass.name(), isDeep=False)
for obj in objlist:
fields = []
fields.append(str(obj.serialNum()))
for attr in attrs:
# jdh 2003-03-07: if the attribute is a dangling object reference, the value
# will be None. This means that dangling references will _not_ be remembered
# across dump/generate/create/insert procedures.
method = getattr(obj, attr.pyGetName())
value = method()
if value is None:
fields.append('')
elif isinstance(value, MiddleObject):
fields.append('%s.%d' % (value.klass().name(),
value.serialNum()))
else:
fields.append(str(value))
out.write(CSVJoiner.joinCSVFields(fields).replace('\r', '\\r'))
out.write('\n')
out.write('\n')
out.write('\n')
if progress:
sys.stderr.write("\n")
class SQLObjectStore(ObjectStore):
"""The MiddleKit SQL Object Store.
TO DO:
* _sqlEcho should be accessible via a config file setting
as stdout, stderr or a filename.
For details on DB API 2.0, including the thread safety levels see:
http://www.python.org/topics/database/DatabaseAPI-2.0.html
"""
## Init ##
def __init__(self, **kwargs):
# @@ 2001-02-12 ce: We probably need a dictionary before kwargs
# for subclasses to pass to us in case they override __init__()
# and end up collecting kwargs themselves
ObjectStore.__init__(self)
self._dbArgs = kwargs
self._connected = False
self._commited = False
self._sqlEcho = None
self._sqlCount = 0
self._pool = None # an optional DBPool
def modelWasSet(self):
"""Perform additional set up of the store after the model is set.
Performs additional set up of the store after the model is set, normally
via setModel() or readModelFileNamed(). This includes checking that
threading conditions are valid, and connecting to the database.
"""
ObjectStore.modelWasSet(self)
# Check thread safety
self._threadSafety = self.threadSafety()
if self._threaded and self._threadSafety == 0:
raise SQLObjectStoreThreadingError('Threaded is True,'
' but the DB API threadsafety is 0.')
# Cache some settings
self._markDeletes = self.setting('DeleteBehavior', 'delete') == 'mark'
# Set up SQL echo
self.setUpSQLEcho()
# Set up attrs for caching
for klass in self.model().allKlassesInOrder():
klass._getMethods = {}
klass._setMethods = {}
for attr in klass.allDataAttrs():
attr._sqlColumnName = None
attr._sqlColumnNames = None
# use dbargs from settings file as defaults
# (args passed to __init__ take precedence)
args = self._dbArgs
self._dbArgs = self.setting('DatabaseArgs', {})
self._dbArgs.update(args)
# print 'dbArgs = %s' % self._dbArgs
# Connect
self.connect()
def setUpSQLEcho(self):
"""Set up the SQL echoing/logging for the store.
The logging is set up according to the setting 'SQLLog'.
See the User's Guide for more info. Invoked by modelWasSet().
"""
setting = self.setting('SQLLog', None)
if setting is None or setting == {}:
self._sqlEcho = None
else:
filename = setting['File']
if filename is None:
self._sqlEcho = None
elif filename == 'stdout':
self._sqlEcho = sys.stdout
elif filename == 'stderr':
self._sqlEcho = sys.stderr
else:
mode = setting.get('Mode', 'write')
assert mode in ['write', 'append']
mode = mode[0]
self._sqlEcho = open(filename, mode)
## Connecting to the db ##
def isConnected(self):
return self._connected
def connect(self):
"""Connect to the database.
Connects to the database only if the store has not already and provided
that the store has a valid model.
The default implementation of connect() is usually sufficient provided
that subclasses have implemented newConnection().
"""
assert self._model, 'Cannot connect:' \
' No model has been attached to this store yet.'
if not self._connected:
self._connection = self.newConnection()
self._connected = True
self.readKlassIds()
poolSize = self.setting('SQLConnectionPoolSize', 0)
if poolSize:
args = self._dbArgs.copy()
self.augmentDatabaseArgs(args, pool=True)
try:
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
except TypeError:
if 'database' in args:
del args['database']
self._pool = DBPool(self.dbapiModule(), poolSize, **args)
else:
raise
def augmentDatabaseArgs(self, args, pool=False):
# give subclasses the opportunity to add or change
# database arguments
pass
def newConnection(self):
"""Return a DB API 2.0 connection.
This is a utility method invoked by connect(). Subclasses should
implement this, making use of self._dbArgs (a dictionary specifying
host, username, etc.) as well as self._model.sqlDatabaseName().
Subclass responsibility.
"""
raise AbstractError(self.__class__)
def readKlassIds(self):
"""Read the klass ids from the SQL database. Invoked by connect()."""
conn, cur = self.executeSQL('select id, name from _MKClassIds;')
try:
klassesById = {}
for klassId, name in cur.fetchall():
assert klassId, 'Id must be a non-zero int.' \
' id=%r, name=%r' % (klassId, name)
try:
klass = self._model.klass(name)
except KeyError:
filename = self._model.filename()
msg = ('%s The database has a class id for %r in the'
' _MKClassIds table, but no such class exists in'
' the model %s. The model and the db are not in sync.'
% (name, name, filename))
raise KeyError(msg)
klassesById[klassId] = klass
klass.setId(klassId)
finally:
self.doneWithConnection(conn)
self._klassesById = klassesById
## Changes ##
def commitInserts(self, allThreads=False):
unknownSerialNums = []
# @@ ... sort here for dependency order
for obj in self._newObjects.items(allThreads):
self._insertObject(obj, unknownSerialNums)
conn = None
try:
for unknownInfo in unknownSerialNums:
stmt = unknownInfo.updateStmt()
conn, cur = self.executeSQL(stmt, conn)
finally:
self.doneWithConnection(conn)
self._newObjects.clear(allThreads)
def _insertObject(self, obj, unknownSerialNums):
# New objects not in the persistent store have serial numbers less than 1
if obj.serialNum() > 0:
try:
rep = repr(obj)
except Exception:
rep = '(repr exception)'
assert obj.serialNum() < 1, 'obj=%s' % rep
# try to get the next ID (if database supports this)
idNum = self.retrieveNextInsertId(obj.klass())
# SQL insert
sql = obj.sqlInsertStmt(unknownSerialNums, idNum)
conn, cur = self.executeSQL(sql)
try:
# Get new id/serial num
if idNum is None:
idNum = self.retrieveLastInsertId(conn, cur)
# Update object
obj.setSerialNum(idNum)
obj.setKey(ObjectKey().initFromObject(obj))
obj.setChanged(False)
# Update our object pool
self._objects[obj.key()] = obj
finally:
self.doneWithConnection(conn)
def retrieveNextInsertId(self, klass):
"""Return the id for the next new object of this class.
Databases which cannot determine the id until the object has been
added return None, signifying that retrieveLastInsertId
should be called to get the id after the insert has been made.
"""
return None
def retrieveLastInsertId(self, conn, cur):
"""Return the id of the last INSERT operation by this connection.
This id is typically a 32-bit int. Used by commitInserts() to get
the correct serial number for the last inserted object.
"""
return cur.lastrowid
def commitUpdates(self, allThreads=False):
conn = None
try:
for obj in self._changedObjects.values(allThreads):
sql = obj.sqlUpdateStmt()
conn, cur = self.executeSQL(sql, conn)
obj.setChanged(False)
finally:
self.doneWithConnection(conn)
self._changedObjects.clear(allThreads)
def commitDeletions(self, allThreads=False):
conn = None
try:
for obj in self._deletedObjects.items(allThreads):
sql = obj.sqlDeleteStmt()
conn, cur = self.executeSQL(sql, conn)
conn.commit()
finally:
self.doneWithConnection(conn)
self._deletedObjects.clear(allThreads)
## Fetching ##
def fetchObject(self, aClass, serialNum, default=NoDefault):
"""Fetch a single object of a specific class and serial number.
aClass can be a Klass object (from the MiddleKit object model),
the name of the class (e.g., a string) or a Python class.
Raises an exception if aClass parameter is invalid, or the object
cannot be located.
"""
klass = self._klassForClass(aClass)
objects = self.fetchObjectsOfClass(klass, serialNum=serialNum, isDeep=False)
count = len(objects)
if count == 0:
if default is NoDefault:
raise UnknownObjectError('aClass = %r, serialNum = %r'
% (aClass, serialNum))
else:
return default
else:
assert count == 1
return objects[0]
def fetchObjectsOfClass(self, aClass,
clauses='', isDeep=True, refreshAttrs=True, serialNum=None, clausesArgs=None):
"""Fetch a list of objects of a specific class.
The list may be empty if no objects are found.
aClass can be a Klass object (from the MiddleKit object model),
the name of the class (e.g., a string) or a Python class.
The clauses argument can be any SQL clauses such as 'where x<5 order by x'.
Obviously, these could be specific to your SQL database, thereby making
your code non-portable. Use your best judgement.
serialNum can be a specific serial number if you are looking for
a specific object. If serialNum is provided, it overrides the clauses.
You should label all arguments other than aClass:
objs = store.fetchObjectsOfClass('Foo', clauses='where x<5')
The reason for labeling is that this method is likely to undergo
improvements in the future which could include additional arguments.
No guarantees are made about the order of the arguments except that
aClass will always be the first.
Raises an exception if aClass parameter is invalid.
"""
klass = self._klassForClass(aClass)
# Fetch objects of subclasses first, because the code below
# will be modifying clauses and serialNum
deepObjs = []
if isDeep:
for subklass in klass.subklasses():
deepObjs.extend(self.fetchObjectsOfClass(
subklass, clauses, isDeep, refreshAttrs, serialNum, clausesArgs))
# Now get objects of this exact class
objs = []
if not klass.isAbstract():
fetchSQLStart = klass.fetchSQLStart()
className = klass.name()
if serialNum is not None:
serialNum = int(serialNum) # make sure it's a valid int
clauses = 'where %s=%d' % (klass.sqlSerialColumnName(), serialNum)
if self._markDeletes:
clauses = self.addDeletedToClauses(clauses)
conn, cur = self.executeSQL(fetchSQLStart + clauses + ';', clausesArgs=clausesArgs)
try:
for row in cur.fetchall():
serialNum = row[0]
key = ObjectKey().initFromClassNameAndSerialNum(className, serialNum)
obj = self._objects.get(key)
if obj is None:
pyClass = klass.pyClass()
obj = pyClass()
assert isinstance(obj, MiddleObject), (
'Not a MiddleObject. obj = %r, type = %r, MiddleObject = %r'
% (obj, type(obj), MiddleObject))
obj.readStoreData(self, row)
obj.setKey(key)
self._objects[key] = obj
else:
# Existing object
if refreshAttrs:
obj.readStoreData(self, row)
objs.append(obj)
finally:
self.doneWithConnection(conn)
objs.extend(deepObjs)
return objs
def refreshObject(self, obj):
assert obj.store() is self
return self.fetchObject(obj.klass(), obj.serialNum())
## Klasses ##
def klassForId(self, id):
return self._klassesById[id]
## Self utility for SQL, connections, cursors, etc. ##
def executeSQL(self, sql, connection=None, commit=False, clausesArgs=None):
"""Execute the given SQL.
This will connect to the database for the first time if necessary.
This method will also log the SQL to self._sqlEcho, if it is not None.
Returns the connection and cursor used and relies on connectionAndCursor()
to obtain these. Note that you can pass in a connection to force a
particular one to be used and a flag to commit immediately.
"""
sql = str(sql) # Excel-based models yield Unicode strings which some db modules don't like
sql = sql.strip()
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
self._sqlCount += 1
if self._sqlEcho:
timestamp = funcs.timestamp()['pretty']
self._sqlEcho.write('SQL %04i. %s %s\n' % (self._sqlCount, timestamp, sql))
self._sqlEcho.flush()
conn, cur = self.connectionAndCursor(connection)
self._executeSQL(cur, sql, clausesArgs)
if commit:
conn.commit()
return conn, cur
def _executeSQL(self, cur, sql, clausesArgs=None):
"""Invoke execute on the cursor with the given SQL.
This is a hook for subclasses that wish to influence this event.
Invoked by executeSQL().
"""
cur.execute(sql, clausesArgs)
def executeSQLTransaction(self, transaction, connection=None, commit=True):
"""Execute the given sequence of SQL statements and commit as transaction."""
if isinstance(transaction, basestring):
transaction = [transaction]
try:
for sql in transaction:
if connection:
self.executeSQL(sql, connection)
else:
connection, cur = self.executeSQL(sql)
except Exception:
if connection and commit:
connection.rollback()
raise
if transaction and connection and commit:
try:
connection.commit()
except Exception:
connection.rollback()
raise
return connection
def executeSQLScript(self, sql, connection=None):
"""Execute the given SQL script.
This uses the nonstandard executescript() method as provided
by the PySQLite adapter.
"""
sql = str(sql).strip()
if not connection:
connection = self.newConnection()
if not hasattr(connection, 'executescript'):
raise AttributeError(
'Script execution not supported by database adapter.')
return connection.executescript(sql)
def setSQLEcho(self, file):
"""Set a file to echo sql statements to, as sent through executeSQL().
None can be passed to turn echo off.
"""
self._sqlEcho = file
def connectionAndCursor(self, connection=None):
"""Return the connection and cursor needed for executing SQL.
Takes into account factors such as setting('Threaded') and the
threadsafety level of the DB API module. You can pass in a connection to
force a particular one to be used. Uses newConnection() and connect().
"""
if aggressiveGC:
import gc
assert gc.isenabled()
gc.collect()
if connection:
conn = connection
elif self._threaded:
if self._pool:
conn = self._pool.connection()
elif self._threadSafety == 1:
conn = self.newConnection()
else: # safety = 2, 3
if not self._connected:
self.connect()
conn = self._connection
else:
# Non-threaded
if not self._connected:
self.connect()
conn = self._connection
cursor = conn.cursor()
return conn, cursor
def threadSafety(self):
"""Return the threadsafety of the DB API module."""
return self.dbapiModule().threadsafety
def dbapiVersion(self):
"""Return the version of the DB API module."""
module = self.dbapiModule()
return '%s %s' % (module.__name__, module.version)
def dbVersion(self):
"""Return the database version.
Subclass responsibility.
"""
raise AbstractError(self.__class__)
def addDeletedToClauses(self, clauses):
"""Modify the given set of clauses so that it filters out records with non-NULL deleted field."""
clauses = clauses.strip()
if clauses.lower().startswith('where'):
where = clauses[5:]
orderByIndex = where.lower().find('order by')
if orderByIndex < 0:
orderBy = ''
else:
where, orderBy = where[:orderByIndex], where[orderByIndex:]
return 'where deleted is null and (%s) %s' % (where, orderBy)
else:
return 'where deleted is null %s' % clauses
## Obj refs ##
def fetchObjRef(self, objRef):
"""Fetch referenced object.
Given an unarchived object reference, this method returns the actual
object for it (or None if the reference is NULL or dangling). While
this method assumes that obj refs are stored as 64-bit numbers containing
the class id and object serial number, subclasses are certainly able to
override that assumption by overriding this method.
"""
assert isinstance(objRef, long), 'type=%r, objRef=%r' % (type(objRef), objRef)
if objRef == 0:
return None
else:
klassId, serialNum = objRefSplit(objRef)
if klassId == 0 or serialNum == 0:
# invalid! we don't use 0 serial numbers
return self.objRefZeroSerialNum(objRef)
klass = self.klassForId(klassId)
# Check if we already have this in memory first
key = ObjectKey()
key.initFromClassNameAndSerialNum(klass.name(), serialNum)
obj = self._objects.get(key)
if obj:
return obj
clauses = 'where %s=%d' % (klass.sqlSerialColumnName(), serialNum)
objs = self.fetchObjectsOfClass(klass, clauses, isDeep=False)
if len(objs) == 1:
return objs[0]
elif len(objs) > 1:
# @@ 2000-11-22 ce: expand the msg with more information
raise ValueError('Multiple objects.')
else:
return self.objRefDangles(objRef)
def objRefInMem(self, objRef):
"""Return referenced object in memory.
Returns the object corresponding to the given objref if and only if it
has been loaded into memory. If the object has never been fetched from
the database, None is returned.
"""
assert isinstance(objRef, long), 'type=%r, objRef=%r' % (type(objRef), objRef)
if objRef == 0:
return 0
else:
klassId, serialNum = objRefSplit(objRef)
if klassId == 0 or serialNum == 0:
# invalid! we don't use 0 serial numbers
return self.objRefZeroSerialNum(objRef)
klass = self.klassForId(klassId)
# return whether we have this object in memory
key = ObjectKey()
key.initFromClassNameAndSerialNum(klass.name(), serialNum)
return self._objects.get(key)
def objRefZeroSerialNum(self, objRef):
"""Raise serial number zero error.
Invoked by fetchObjRef() if either the class or the object serial
number is zero.
"""
raise ObjRefZeroSerialNumError(*objRefSplit(objRef))
def objRefDangles(self, objRef):
"""Raise dangling reference error.
Invoked by fetchObjRef() if there is no possible target object
for the given objRef.
E.g., this can happen for a dangling reference. This method invokes
self.warning() and includes the objRef as decimal, hexadecimal
and class:obj numbers.
"""
raise ObjRefDanglesError(*objRefSplit(objRef))
## Special Cases ##
def filterDateTimeDelta(self, dtd):
"""Adapt DateTimeDeltas.
Some databases have no TIME type and therefore will not return
DateTimeDeltas. This utility method is overridden by subclasses
as appropriate and invoked by the test suite.
"""
return dtd
def sqlNowCall(self):
"""Get current DateTime."""
return 'CURRENT_TIMESTAMP'
## Self util ##
def doneWithConnection(self, conn):
"""Invoked by self when a connection is no longer needed.
The default behavior is to commit and close the connection.
"""
if conn is not None:
# Starting with 1.2.0, MySQLdb disables autocommit by default,
# as required by the DB-API standard (PEP-249). If you are using
# InnoDB tables or some other type of transactional table type,
# you'll need to do connection.commit() before closing the connection,
# or else none of your changes will be written to the database.
try:
conn.commit()
except Exception:
pass
conn.close()
## Debugging ##
def dumpTables(self, out=None):
if out is None:
out = sys.stdout
out.write('DUMPING TABLES\n')
out.write('BEGIN\n')
conn = None
try:
for klass in self.model().klasses().values():
out.write(klass.name() + '\n')
conn, cur = self.executeSQL('select * from %s;'
% klass.name(), conn)
out.write(str(self._cursor.fetchall()))
out.write('\n')
finally:
self.doneWithConnection(conn)
out.write('END\n')
def dumpKlassIds(self, out=None):
if out is None:
out = sys.stdout
wr = out.write('DUMPING KLASS IDs\n')
for klass in self.model().klasses().values():
out.write('%25s %2i\n' % (klass.name(), klass.id()))
out.write('\n')
def dumpObjectStore(self, out=None, progress=False):
if out is None:
out = sys.stdout
for klass in self.model().klasses().values():
if progress:
sys.stderr.write(".")
out.write('%s objects\n' % (klass.name()))
attrs = [attr for attr in klass.allAttrs() if attr.hasSQLColumn()]
colNames = [attr.name() for attr in attrs]
colNames.insert(0, klass.sqlSerialColumnName())
out.write(CSVJoiner.joinCSVFields(colNames) + "\n")
# write out a line for each object in this class
objlist = self.fetchObjectsOfClass(klass.name(), isDeep=False)
for obj in objlist:
fields = []
fields.append(str(obj.serialNum()))
for attr in attrs:
# jdh 2003-03-07: if the attribute is a dangling object reference, the value
# will be None. This means that dangling references will _not_ be remembered
# across dump/generate/create/insert procedures.
method = getattr(obj, attr.pyGetName())
value = method()
if value is None:
fields.append('')
elif isinstance(value, MiddleObject):
fields.append('%s.%d' % (value.klass().name(),
value.serialNum()))
else:
fields.append(str(value))
out.write(CSVJoiner.joinCSVFields(fields).replace('\r', '\\r'))
out.write('\n')
out.write('\n')
out.write('\n')
if progress:
sys.stderr.write("\n")
