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

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from . import dbconnection

from . import sqlbuilder

from .compat import string_type

__all__ = ['SelectResults']

class SelectResults(object):

IterationClass = dbconnection.Iteration

def __init__(self, sourceClass, clause, clauseTables=None,

**ops):

self.sourceClass = sourceClass

if clause is None or isinstance(clause, str) and clause == 'all':

clause = sqlbuilder.SQLTrueClause

if not isinstance(clause, sqlbuilder.SQLExpression):

clause = sqlbuilder.SQLConstant(clause)

self.clause = clause

self.ops = ops

if ops.get('orderBy', sqlbuilder.NoDefault) is sqlbuilder.NoDefault:

ops['orderBy'] = sourceClass.sqlmeta.defaultOrder

orderBy = ops['orderBy']

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

orderBy = list(map(self._mungeOrderBy, orderBy))

else:

orderBy = self._mungeOrderBy(orderBy)

ops['dbOrderBy'] = orderBy

if 'connection' in ops and ops['connection'] is None:

del ops['connection']

if ops.get('limit', None):

assert not ops.get('start', None) and not ops.get('end', None), \

"'limit' cannot be used with 'start' or 'end'"

ops["start"] = 0

ops["end"] = ops.pop("limit")

tablesSet = sqlbuilder.tablesUsedSet(self.clause,

self._getConnection().dbName)

if clauseTables:

for table in clauseTables:

tablesSet.add(table)

self.clauseTables = clauseTables

# Explicitly post-adding-in sqlmeta.table,

# sqlbuilder.Select will handle sqlrepr'ing and dupes.

self.tables = list(tablesSet) + [sourceClass.sqlmeta.table]

def queryForSelect(self):

columns = [self.sourceClass.q.id] + \

[getattr(self.sourceClass.q, x.name)

for x in self.sourceClass.sqlmeta.columnList]

query = sqlbuilder.Select(columns,

where=self.clause,

join=self.ops.get(

'join', sqlbuilder.NoDefault),

distinct=self.ops.get('distinct', False),

lazyColumns=self.ops.get(

'lazyColumns', False),

start=self.ops.get('start', 0),

end=self.ops.get('end', None),

orderBy=self.ops.get(

'dbOrderBy', sqlbuilder.NoDefault),

reversed=self.ops.get('reversed', False),

staticTables=self.tables,

forUpdate=self.ops.get('forUpdate', False))

return query

def __repr__(self):

return "<%s at %x>" % (self.__class__.__name__, id(self))

def _getConnection(self):

return self.ops.get('connection') or self.sourceClass._connection

def __str__(self):

conn = self._getConnection()

return conn.queryForSelect(self)

def _mungeOrderBy(self, orderBy):

if isinstance(orderBy, string_type) and orderBy.startswith('-'):

orderBy = orderBy[1:]

desc = True

else:

desc = False

if isinstance(orderBy, string_type):

if orderBy in self.sourceClass.sqlmeta.columns:

val = getattr(self.sourceClass.q,

self.sourceClass.sqlmeta.columns[orderBy].name)

if desc:

return sqlbuilder.DESC(val)

else:

return val

else:

orderBy = sqlbuilder.SQLConstant(orderBy)

if desc:

return sqlbuilder.DESC(orderBy)

else:

return orderBy

else:

return orderBy

def clone(self, **newOps):

ops = self.ops.copy()

ops.update(newOps)

return self.__class__(self.sourceClass, self.clause,

self.clauseTables, **ops)

def orderBy(self, orderBy):

return self.clone(orderBy=orderBy)

def connection(self, conn):

return self.clone(connection=conn)

def limit(self, limit):

return self[:limit]

def lazyColumns(self, value):

return self.clone(lazyColumns=value)

def reversed(self):

return self.clone(reversed=not self.ops.get('reversed', False))

def distinct(self):

return self.clone(distinct=True)

def newClause(self, new_clause):

return self.__class__(self.sourceClass, new_clause,

self.clauseTables, **self.ops)

def filter(self, filter_clause):

if filter_clause is None:

# None doesn't filter anything, it's just a no-op:

return self

clause = self.clause

if isinstance(clause, string_type):

clause = sqlbuilder.SQLConstant('(%s)' % clause)

return self.newClause(sqlbuilder.AND(clause, filter_clause))

def __getitem__(self, value):

if isinstance(value, slice):

assert not value.step, "Slices do not support steps"

if not value.start and not value.stop:

# No need to copy, I'm immutable

return self

# Negative indexes aren't handled (and everything we

# don't handle ourselves we just create a list to

# handle)

if (value.start and value.start < 0) \

or (value.stop and value.stop < 0):

if value.start:

if value.stop:

return list(self)[value.start:value.stop]

return list(self)[value.start:]

return list(self)[:value.stop]

if value.start:

assert value.start >= 0

start = self.ops.get('start', 0) + value.start

if value.stop is not None:

assert value.stop >= 0

if value.stop < value.start:

# an empty result:

end = start

else:

end = value.stop + self.ops.get('start', 0)

if self.ops.get('end', None) is not None and \

self.ops['end'] < end:

# truncated by previous slice:

end = self.ops['end']

else:

end = self.ops.get('end', None)

else:

start = self.ops.get('start', 0)

end = value.stop + start

if self.ops.get('end', None) is not None \

and self.ops['end'] < end:

end = self.ops['end']

return self.clone(start=start, end=end)

else:

if value < 0:

return list(iter(self))[value]

else:

start = self.ops.get('start', 0) + value

return list(self.clone(start=start, end=start + 1))[0]

def __iter__(self):

# @@: This could be optimized, using a simpler algorithm

# since we don't have to worry about garbage collection,

# etc., like we do with .lazyIter()

return iter(list(self.lazyIter()))

def lazyIter(self):

"""

Returns an iterator that will lazily pull rows out of the

database and return SQLObject instances

"""

conn = self._getConnection()

return conn.iterSelect(self)

def accumulate(self, *expressions):

""" Use accumulate expression(s) to select result

using another SQL select through current

connection.

Return the accumulate result

"""

conn = self._getConnection()

exprs = []

for expr in expressions:

if not isinstance(expr, sqlbuilder.SQLExpression):

expr = sqlbuilder.SQLConstant(expr)

exprs.append(expr)

return conn.accumulateSelect(self, *exprs)

def count(self):

""" Counting elements of current select results """

assert not self.ops.get('start') and not self.ops.get('end'), \

"start/end/limit have no meaning with 'count'"

assert not (self.ops.get('distinct')

and (self.ops.get('start') or self.ops.get('end'))), \

"distinct-counting of sliced objects is not supported"

if self.ops.get('distinct'):

# Column must be specified, so we are using unique ID column.

# COUNT(DISTINCT column) is supported by MySQL and PostgreSQL,

# but not by SQLite. Perhaps more portable would be subquery:

# SELECT COUNT(*) FROM (SELECT DISTINCT id FROM table)

count = self.accumulate(

'COUNT(DISTINCT %s)' % self._getConnection().sqlrepr(

self.sourceClass.q.id))

else:

count = self.accumulate('COUNT(*)')

if self.ops.get('start'):

count -= self.ops['start']

if self.ops.get('end'):

count = min(self.ops['end'] - self.ops.get('start', 0), count)

return count

def accumulateMany(self, *attributes):

""" Making the expressions for count/sum/min/max/avg

of a given select result attributes.

`attributes` must be a list/tuple of pairs (func_name, attribute);

`attribute` can be a column name (like 'a_column')

or a dot-q attribute (like Table.q.aColumn)

"""

expressions = []

conn = self._getConnection()

if self.ops.get('distinct'):

distinct = 'DISTINCT '

else:

distinct = ''

for func_name, attribute in attributes:

if not isinstance(attribute, str):

attribute = conn.sqlrepr(attribute)

expression = '%s(%s%s)' % (func_name, distinct, attribute)

expressions.append(expression)

return self.accumulate(*expressions)

def accumulateOne(self, func_name, attribute):

""" Making the sum/min/max/avg of a given select result attribute.

`attribute` can be a column name (like 'a_column')

or a dot-q attribute (like Table.q.aColumn)

"""

return self.accumulateMany((func_name, attribute))

def sum(self, attribute):

return self.accumulateOne("SUM", attribute)

def min(self, attribute):

return self.accumulateOne("MIN", attribute)

def avg(self, attribute):

return self.accumulateOne("AVG", attribute)

def max(self, attribute):

return self.accumulateOne("MAX", attribute)

def getOne(self, default=sqlbuilder.NoDefault):

"""

If a query is expected to only return a single value,

using ``.getOne()`` will return just that value.

If not results are found, ``SQLObjectNotFound`` will be

raised, unless you pass in a default value (like

``.getOne(None)``).

If more than one result is returned,

``SQLObjectIntegrityError`` will be raised.

"""

from . import main

results = list(self)

if not results:

if default is sqlbuilder.NoDefault:

raise main.SQLObjectNotFound(

"No results matched the query for %s"

% self.sourceClass.__name__)

return default

if len(results) > 1:

raise main.SQLObjectIntegrityError(

"More than one result returned from query: %s"

% results)

return results[0]

def throughTo(self):

class _throughTo_getter(object):

def __init__(self, inst):

self.sresult = inst

def __getattr__(self, attr):

return self.sresult._throughTo(attr)

return _throughTo_getter(self)

throughTo = property(throughTo)

def _throughTo(self, attr):

otherClass = None

orderBy = sqlbuilder.NoDefault

ref = self.sourceClass.sqlmeta.columns.get(

attr.endswith('ID') and attr or attr + 'ID', None)

if ref and ref.foreignKey:

otherClass, clause = self._throughToFK(ref)

else:

join = [x for x in self.sourceClass.sqlmeta.joins

if x.joinMethodName == attr]

if join:

join = join[0]

orderBy = join.orderBy

if hasattr(join, 'otherColumn'):

otherClass, clause = self._throughToRelatedJoin(join)

else:

otherClass, clause = self._throughToMultipleJoin(join)

if not otherClass:

raise AttributeError(

"throughTo argument (got %s) should be "

"name of foreignKey or SQL*Join in %s" % (attr,

self.sourceClass))

return otherClass.select(clause,

orderBy=orderBy,

connection=self._getConnection())

def _throughToFK(self, col):

otherClass = getattr(self.sourceClass, "_SO_class_" + col.foreignKey)

colName = col.name

query = self.queryForSelect().newItems([

sqlbuilder.ColumnAS(getattr(self.sourceClass.q, colName), colName)

]).orderBy(None).distinct()

query = sqlbuilder.Alias(query,

"%s_%s" % (self.sourceClass.__name__,

col.name))

return otherClass, otherClass.q.id == getattr(query.q, colName)

def _throughToMultipleJoin(self, join):

otherClass = join.otherClass

colName = join.soClass.sqlmeta.style.\

dbColumnToPythonAttr(join.joinColumn)

query = self.queryForSelect().newItems(

[sqlbuilder.ColumnAS(self.sourceClass.q.id, 'id')]).\

orderBy(None).distinct()

query = sqlbuilder.Alias(query,

"%s_%s" % (self.sourceClass.__name__,

join.joinMethodName))

joinColumn = getattr(otherClass.q, colName)

return otherClass, joinColumn == query.q.id

def _throughToRelatedJoin(self, join):

otherClass = join.otherClass

intTable = sqlbuilder.Table(join.intermediateTable)

colName = join.joinColumn

query = self.queryForSelect().newItems(

[sqlbuilder.ColumnAS(self.sourceClass.q.id, 'id')]).\

orderBy(None).distinct()

query = sqlbuilder.Alias(query,

"%s_%s" % (self.sourceClass.__name__,

join.joinMethodName))

clause = sqlbuilder.AND(

otherClass.q.id == getattr(intTable, join.otherColumn),

getattr(intTable, colName) == query.q.id)

return otherClass, clause

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

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