sqlobject/sqlobject/joins.py at master · sqlobject/sqlobject · GitHub

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from itertools import count

from . import boundattributes

from . import classregistry

from . import events

from . import sresults

from . import styles

from . import sqlbuilder

from .styles import capword

__all__ = ['MultipleJoin', 'SQLMultipleJoin', 'RelatedJoin', 'SQLRelatedJoin',

'SingleJoin', 'ManyToMany', 'OneToMany']

creationOrder = count()

NoDefault = sqlbuilder.NoDefault

def getID(obj):

try:

return obj.id

except AttributeError:

return int(obj)

class Join(object):

def __init__(self, otherClass=None, **kw):

kw['otherClass'] = otherClass

self.kw = kw

self._joinMethodName = self.kw.pop('joinMethodName', None)

self.creationOrder = next(creationOrder)

def _set_joinMethodName(self, value):

assert self._joinMethodName == value or self._joinMethodName is None, \

"You have already given an explicit joinMethodName (%s), " \

"and you are now setting it to %s" % (self._joinMethodName, value)

self._joinMethodName = value

def _get_joinMethodName(self):

return self._joinMethodName

joinMethodName = property(_get_joinMethodName, _set_joinMethodName)

name = joinMethodName

def withClass(self, soClass):

if 'joinMethodName' in self.kw:

self._joinMethodName = self.kw['joinMethodName']

del self.kw['joinMethodName']

return self.baseClass(creationOrder=self.creationOrder,

soClass=soClass,

joinDef=self,

joinMethodName=self._joinMethodName,

**self.kw)

# A join is separate from a foreign key, i.e., it is

# many-to-many, or one-to-many where the *other* class

# has the foreign key.

class SOJoin(object):

def __init__(self,

creationOrder,

soClass=None,

otherClass=None,

joinColumn=None,

joinMethodName=None,

orderBy=NoDefault,

joinDef=None):

self.creationOrder = creationOrder

self.soClass = soClass

self.joinDef = joinDef

self.otherClassName = otherClass

classregistry.registry(soClass.sqlmeta.registry).addClassCallback(

otherClass, self._setOtherClass)

self.joinColumn = joinColumn

self.joinMethodName = joinMethodName

self._orderBy = orderBy

if not self.joinColumn:

# Here we set up the basic join, which is

# one-to-many, where the other class points to

# us.

self.joinColumn = styles.getStyle(

self.soClass).tableReference(self.soClass.sqlmeta.table)

def orderBy(self):

if self._orderBy is NoDefault:

self._orderBy = self.otherClass.sqlmeta.defaultOrder

return self._orderBy

orderBy = property(orderBy)

def _setOtherClass(self, cls):

self.otherClass = cls

def hasIntermediateTable(self):

return False

def _applyOrderBy(self, results, defaultSortClass):

if self.orderBy is not None:

doSort(results, self.orderBy)

return results

class MinType(object):

"""Sort less than everything, for handling None's in the results"""

# functools.total_ordering would simplify this

def __lt__(self, other):

if self is other:

return False

return True

def __eq__(self, other):

return self is other

def __gt__(self, other):

return False

def __le__(self, other):

return True

def __ge__(self, other):

if self is other:

return True

return False

Min = MinType()

def doSort(results, orderBy):

if isinstance(orderBy, (tuple, list)):

if len(orderBy) == 1:

orderBy = orderBy[0]

else:

# Rely on stable sort results, since this is simpler

# than trying to munge everything into a single sort key

doSort(results, orderBy[0])

doSort(results, orderBy[1:])

return

if isinstance(orderBy, sqlbuilder.DESC) \

and isinstance(orderBy.expr, sqlbuilder.SQLObjectField):

orderBy = '-' + orderBy.expr.original

elif isinstance(orderBy, sqlbuilder.SQLObjectField):

orderBy = orderBy.original

# @@: but we don't handle more complex expressions for orderings

if orderBy.startswith('-'):

orderBy = orderBy[1:]

reverse = True

else:

reverse = False

def sortkey(x, attr=orderBy):

a = getattr(x, attr)

if a is None:

return Min

return a

results.sort(key=sortkey, reverse=reverse)

# This is a one-to-many

class SOMultipleJoin(SOJoin):

def __init__(self, addRemoveName=None, **kw):

# addRemovePrefix is something like @@

SOJoin.__init__(self, **kw)

# Here we generate the method names

if not self.joinMethodName:

name = self.otherClassName[0].lower() + self.otherClassName[1:]

if name.endswith('s'):

name += "es"

else:

name += "s"

self.joinMethodName = name

if addRemoveName:

self.addRemoveName = addRemoveName

else:

self.addRemoveName = capword(self.otherClassName)

def performJoin(self, inst):

ids = inst._connection._SO_selectJoin(

self.otherClass,

self.joinColumn,

inst.id)

if inst.sqlmeta._perConnection:

conn = inst._connection

else:

conn = None

return self._applyOrderBy(

[self.otherClass.get(id, conn) for (id,) in ids if id is not None],

self.otherClass)

def _dbNameToPythonName(self):

for column in self.otherClass.sqlmeta.columns.values():

if column.dbName == self.joinColumn:

return column.name

return self.soClass.sqlmeta.style.dbColumnToPythonAttr(self.joinColumn)

class MultipleJoin(Join):

baseClass = SOMultipleJoin

class SOSQLMultipleJoin(SOMultipleJoin):

def performJoin(self, inst):

if inst.sqlmeta._perConnection:

conn = inst._connection

else:

conn = None

pythonColumn = self._dbNameToPythonName()

results = self.otherClass.select(

getattr(self.otherClass.q, pythonColumn) == inst.id,

connection=conn)

return results.orderBy(self.orderBy)

class SQLMultipleJoin(Join):

baseClass = SOSQLMultipleJoin

# This is a many-to-many join, with an intermediary table

class SORelatedJoin(SOMultipleJoin):

def __init__(self,

otherColumn=None,

intermediateTable=None,

createRelatedTable=True,

**kw):

self.intermediateTable = intermediateTable

self.otherColumn = otherColumn

self.createRelatedTable = createRelatedTable

SOMultipleJoin.__init__(self, **kw)

classregistry.registry(

self.soClass.sqlmeta.registry).addClassCallback(

self.otherClassName, self._setOtherRelatedClass)

def _setOtherRelatedClass(self, otherClass):

if not self.intermediateTable:

names = [self.soClass.sqlmeta.table,

otherClass.sqlmeta.table]

names.sort()

self.intermediateTable = '%s_%s' % (names[0], names[1])

if not self.otherColumn:

self.otherColumn = self.soClass.sqlmeta.style.tableReference(

otherClass.sqlmeta.table)

def hasIntermediateTable(self):

return True

def performJoin(self, inst):

ids = inst._connection._SO_intermediateJoin(

self.intermediateTable,

self.otherColumn,

self.joinColumn,

inst.id)

if inst.sqlmeta._perConnection:

conn = inst._connection

else:

conn = None

return self._applyOrderBy(

[self.otherClass.get(id, conn) for (id,) in ids if id is not None],

self.otherClass)

def remove(self, inst, other):

inst._connection._SO_intermediateDelete(

self.intermediateTable,

self.joinColumn,

getID(inst),

self.otherColumn,

getID(other))

def add(self, inst, other):

inst._connection._SO_intermediateInsert(

self.intermediateTable,

self.joinColumn,

getID(inst),

self.otherColumn,

getID(other))

class RelatedJoin(MultipleJoin):

baseClass = SORelatedJoin

# helper classes to SQLRelatedJoin

class OtherTableToJoin(sqlbuilder.SQLExpression):

def __init__(self, otherTable, otherIdName, interTable, joinColumn, alias):

self.otherTable = otherTable

self.otherIdName = otherIdName

self.interTable = interTable

self.joinColumn = joinColumn

self.alias = alias

def tablesUsedImmediate(self):

return [

'%s %s' % (self.otherTable, self.alias)

if self.alias else self.otherTable,

self.interTable,

]

def __sqlrepr__(self, db):

return '%s.%s = %s.%s' % (

self.alias if self.alias else self.otherTable,

self.otherIdName, self.interTable, self.joinColumn)

class JoinToTable(sqlbuilder.SQLExpression):

def __init__(self, table, idName, interTable, joinColumn, alias):

self.table = table

self.idName = idName

self.interTable = interTable

self.joinColumn = joinColumn

self.alias = alias

def tablesUsedImmediate(self):

return [

'%s %s' % (self.table, self.alias)

if self.alias else self.table,

self.interTable,

]

def __sqlrepr__(self, db):

return '%s.%s = %s.%s' % (

self.interTable, self.joinColumn,

self.alias if self.alias else self.table, self.idName)

class TableToId(sqlbuilder.SQLExpression):

def __init__(self, table, idName, idValue, alias):

self.table = table

self.idName = idName

self.idValue = idValue

self.alias = alias

def tablesUsedImmediate(self):

return [

'%s %s' % (self.table, self.alias)

if self.alias else self.table,

]

def __sqlrepr__(self, db):

return '%s.%s = %s' % (

self.alias if self.alias else self.table,

self.idName, self.idValue)

class SQLJoinSelectResults(sresults.SelectResults):

def filter(self, filter_clause):

clause_tables = filter_clause.tablesUsed(None)

if self._SOSQLRelatedJoin_realSourceClass.sqlmeta.table \

in clause_tables:

tableClass = self._SOSQLRelatedJoin_realSourceClass.__name__

raise ValueError(

"Using table '%s' in the filter expression without an alias "

"could produce wrong SQL. Most probably you need "

"Alias(%s, '_SO_SQLRelatedJoin_OtherTable') instead."

% (tableClass, tableClass)

)

return sresults.SelectResults.filter(self, filter_clause)

class SOSQLRelatedJoin(SORelatedJoin):

def performJoin(self, inst):

if inst.sqlmeta._perConnection:

conn = inst._connection

else:

conn = None

needAlias = self.soClass is self.otherClass

if needAlias:

source = sqlbuilder.Alias(

self.otherClass, '_SO_SQLRelatedJoin_OtherTable')

sresultsClass = SQLJoinSelectResults

else:

source = self.otherClass

sresultsClass = self.otherClass.SelectResultsClass

results = sresultsClass(

source,

sqlbuilder.AND(

OtherTableToJoin(

self.otherClass.sqlmeta.table,

self.otherClass.sqlmeta.idName,

self.intermediateTable, self.otherColumn,

'_SO_SQLRelatedJoin_OtherTable' if needAlias else '',

JoinToTable(

self.soClass.sqlmeta.table, self.soClass.sqlmeta.idName,

self.intermediateTable, self.joinColumn,

'_SO_SQLRelatedJoin_ThisTable' if needAlias else '',

TableToId(

self.soClass.sqlmeta.table, self.soClass.sqlmeta.idName,

inst.id,

'_SO_SQLRelatedJoin_ThisTable' if needAlias else '',

clauseTables=(

'%s _SO_SQLRelatedJoin_ThisTable' % self.soClass.sqlmeta.table

if needAlias else self.soClass.sqlmeta.table,

'%s _SO_SQLRelatedJoin_OtherTable' %

self.otherClass.sqlmeta.table

if needAlias else self.otherClass.sqlmeta.table,

self.intermediateTable,

connection=conn,

orderBy=self.orderBy,

)

results._SOSQLRelatedJoin_realSourceClass = self.otherClass

return results

class SQLRelatedJoin(RelatedJoin):

baseClass = SOSQLRelatedJoin

class SOSingleJoin(SOMultipleJoin):

def __init__(self, **kw):

self.makeDefault = kw.pop('makeDefault', False)

SOMultipleJoin.__init__(self, **kw)

def performJoin(self, inst):

if inst.sqlmeta._perConnection:

conn = inst._connection

else:

conn = None

pythonColumn = self._dbNameToPythonName()

results = self.otherClass.select(

getattr(self.otherClass.q, pythonColumn) == inst.id,

connection=conn

)

if results.count() == 0:

if not self.makeDefault:

return None

else:

kw = {self.soClass.sqlmeta.style.

instanceIDAttrToAttr(pythonColumn): inst}

# instanciating the otherClass with all

return self.otherClass(**kw)

else:

return results[0]

class SingleJoin(Join):

baseClass = SOSingleJoin

class SOManyToMany(object):

def __init__(self, soClass, name, join,

intermediateTable, joinColumn, otherColumn,

createJoinTable, **attrs):

self.name = name

self.intermediateTable = intermediateTable

self.joinColumn = joinColumn

self.otherColumn = otherColumn

self.createJoinTable = createJoinTable

self.soClass = self.otherClass = None

for name, value in attrs.items():

setattr(self, name, value)

classregistry.registry(

soClass.sqlmeta.registry).addClassCallback(

join, self._setOtherClass)

classregistry.registry(

soClass.sqlmeta.registry).addClassCallback(

soClass.__name__, self._setThisClass)

def _setThisClass(self, soClass):

self.soClass = soClass

if self.soClass and self.otherClass:

self._finishSet()

def _setOtherClass(self, otherClass):

self.otherClass = otherClass

if self.soClass and self.otherClass:

self._finishSet()

def _finishSet(self):

if self.intermediateTable is None:

names = [self.soClass.sqlmeta.table,

self.otherClass.sqlmeta.table]

names.sort()

self.intermediateTable = '%s_%s' % (names[0], names[1])

if not self.otherColumn:

self.otherColumn = self.soClass.sqlmeta.style.tableReference(

self.otherClass.sqlmeta.table)

if not self.joinColumn:

self.joinColumn = styles.getStyle(

self.soClass).tableReference(self.soClass.sqlmeta.table)

events.listen(self.event_CreateTableSignal,

self.soClass, events.CreateTableSignal)

events.listen(self.event_CreateTableSignal,

self.otherClass, events.CreateTableSignal)

self.clause = (

(self.otherClass.q.id

== sqlbuilder.Field(self.intermediateTable, self.otherColumn))

& (sqlbuilder.Field(self.intermediateTable, self.joinColumn)

== self.soClass.q.id))

def __get__(self, obj, type):

if obj is None:

return self

query = (

(self.otherClass.q.id

== sqlbuilder.Field(self.intermediateTable, self.otherColumn))

& (sqlbuilder.Field(self.intermediateTable, self.joinColumn)

== obj.id))

select = self.otherClass.select(query)

return _ManyToManySelectWrapper(obj, self, select)

def event_CreateTableSignal(self, soClass, connection, extra_sql,

post_funcs):

if self.createJoinTable:

post_funcs.append(self.event_CreateTableSignalPost)

def event_CreateTableSignalPost(self, soClass, connection):

if connection.tableExists(self.intermediateTable):

return

connection._SO_createJoinTable(self)

class ManyToMany(boundattributes.BoundFactory):

factory_class = SOManyToMany

__restrict_attributes__ = (

'join', 'intermediateTable',

'joinColumn', 'otherColumn', 'createJoinTable')

__unpackargs__ = ('join',)

# Default values:

intermediateTable = None

joinColumn = None

otherColumn = None

createJoinTable = True

class _ManyToManySelectWrapper(object):

def __init__(self, forObject, join, select):

self.forObject = forObject

self.join = join

self.select = select

def __getattr__(self, attr):

# @@: This passes through private variable access too... should it?

# Also magic methods, like __str__

return getattr(self.select, attr)

def __repr__(self):

return '<%s for: %s>' % (self.__class__.__name__, repr(self.select))

def __str__(self):

return str(self.select)

def __iter__(self):

return iter(self.select)

def __getitem__(self, key):

return self.select[key]

def add(self, obj):

obj._connection._SO_intermediateInsert(

self.join.intermediateTable,

self.join.joinColumn,

getID(self.forObject),

self.join.otherColumn,

getID(obj))

def remove(self, obj):

obj._connection._SO_intermediateDelete(

self.join.intermediateTable,

self.join.joinColumn,

getID(self.forObject),

self.join.otherColumn,

getID(obj))

def create(self, **kw):

obj = self.join.otherClass(**kw)

self.add(obj)

return obj

class SOOneToMany(object):

def __init__(self, soClass, name, join, joinColumn, **attrs):

self.soClass = soClass

self.name = name

self.joinColumn = joinColumn

for name, value in attrs.items():

setattr(self, name, value)

classregistry.registry(

soClass.sqlmeta.registry).addClassCallback(

join, self._setOtherClass)

def _setOtherClass(self, otherClass):

self.otherClass = otherClass

if not self.joinColumn:

self.joinColumn = styles.getStyle(

self.soClass).tableReference(self.soClass.sqlmeta.table)

self.clause = (

sqlbuilder.Field(self.otherClass.sqlmeta.table, self.joinColumn)

== self.soClass.q.id)

def __get__(self, obj, type):

if obj is None:

return self

query = (

sqlbuilder.Field(self.otherClass.sqlmeta.table, self.joinColumn)

== obj.id)

select = self.otherClass.select(query)

return _OneToManySelectWrapper(obj, self, select)

class OneToMany(boundattributes.BoundFactory):

factory_class = SOOneToMany

__restrict_attributes__ = (

'join', 'joinColumn')

__unpackargs__ = ('join',)

# Default values:

joinColumn = None

class _OneToManySelectWrapper(object):

def __init__(self, forObject, join, select):

self.forObject = forObject

self.join = join

self.select = select

def __getattr__(self, attr):

# @@: This passes through private variable access too... should it?

# Also magic methods, like __str__

return getattr(self.select, attr)

def __repr__(self):

return '<%s for: %s>' % (self.__class__.__name__, repr(self.select))

def __str__(self):

return str(self.select)

def __iter__(self):

return iter(self.select)

def __getitem__(self, key):

return self.select[key]

def create(self, **kw):

kw[self.join.joinColumn] = self.forObject.id

return self.join.otherClass(**kw)

sqlobject/sqlobject/joins.py at master · sqlobject/sqlobject · GitHub

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