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queryset-refactor: The Oracle changes necessary for [7426]. I can't test these

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at the moment, but they should be close to correct.

Refs #6956.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@7427 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick 2008-04-16 02:58:26 +00:00
parent 1add6fb366
commit f2b64c0c4e
3 changed files with 137 additions and 117 deletions
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6
django/db/backends/__init__.py
View File

@ -49,7 +49,7 @@ class BaseDatabaseFeatures(object):
supports_constraints = True
supports_tablespaces = False
uses_case_insensitive_names = False
uses_custom_queryset = False
uses_custom_query_class = False
empty_fetchmany_value = []
class BaseDatabaseOperations(object):
@ -199,11 +199,11 @@ class BaseDatabaseOperations(object):
"""
return 'DEFAULT'
def query_set_class(self, DefaultQuerySet):
def query_class(self, DefaultQueryClass):
"""
Given the default QuerySet class, returns a custom QuerySet class
to use for this backend. Returns None if a custom QuerySet isn't used.
See also BaseDatabaseFeatures.uses_custom_queryset, which regulates
See also BaseDatabaseFeatures.uses_custom_query_class, which regulates
whether this method is called at all.
"""
return None

118
django/db/backends/oracle/base.py
View File

@ -4,10 +4,10 @@ Oracle database backend for Django.
Requires cx_Oracle: http://www.python.net/crew/atuining/cx_Oracle/
"""
import datetime
import os
from django.db.backends import BaseDatabaseWrapper, BaseDatabaseFeatures, BaseDatabaseOperations, util
from django.db.backends.oracle import query
from django.utils.datastructures import SortedDict
from django.utils.encoding import smart_str, force_unicode
@ -30,7 +30,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
needs_upper_for_iops = True
supports_tablespaces = True
uses_case_insensitive_names = True
uses_custom_queryset = True
uses_custom_query_class = True
class DatabaseOperations(BaseDatabaseOperations):
def autoinc_sql(self, table, column):
@ -99,118 +99,8 @@ class DatabaseOperations(BaseDatabaseOperations):
def max_name_length(self):
return 30
def query_set_class(self, DefaultQuerySet):
# Getting the base default `Query` object.
DefaultQuery = DefaultQuerySet().query.__class__
class OracleQuery(DefaultQuery):
def resolve_columns(self, row, fields=()):
from django.db.models.fields import DateField, DateTimeField, \
TimeField, BooleanField, NullBooleanField, DecimalField, Field
values = []
for value, field in map(None, row, fields):
if isinstance(value, Database.LOB):
value = value.read()
# Oracle stores empty strings as null. We need to undo this in
# order to adhere to the Django convention of using the empty
# string instead of null, but only if the field accepts the
# empty string.
if value is None and isinstance(field, Field) and field.empty_strings_allowed:
value = u''
# Convert 1 or 0 to True or False
elif value in (1, 0) and isinstance(field, (BooleanField, NullBooleanField)):
value = bool(value)
# Convert floats to decimals
elif value is not None and isinstance(field, DecimalField):
value = util.typecast_decimal(field.format_number(value))
# cx_Oracle always returns datetime.datetime objects for
# DATE and TIMESTAMP columns, but Django wants to see a
# python datetime.date, .time, or .datetime. We use the type
# of the Field to determine which to cast to, but it's not
# always available.
# As a workaround, we cast to date if all the time-related
# values are 0, or to time if the date is 1/1/1900.
# This could be cleaned a bit by adding a method to the Field
# classes to normalize values from the database (the to_python
# method is used for validation and isn't what we want here).
elif isinstance(value, Database.Timestamp):
# In Python 2.3, the cx_Oracle driver returns its own
# Timestamp object that we must convert to a datetime class.
if not isinstance(value, datetime.datetime):
value = datetime.datetime(value.year, value.month, value.day, value.hour,
value.minute, value.second, value.fsecond)
if isinstance(field, DateTimeField):
pass # DateTimeField subclasses DateField so must be checked first.
elif isinstance(field, DateField):
value = value.date()
elif isinstance(field, TimeField) or (value.year == 1900 and value.month == value.day == 1):
value = value.time()
elif value.hour == value.minute == value.second == value.microsecond == 0:
value = value.date()
values.append(value)
return values
def as_sql(self, with_limits=True):
"""
Creates the SQL for this query. Returns the SQL string and list
of parameters. This is overriden from the original Query class
to accommodate Oracle's limit/offset SQL.
If 'with_limits' is False, any limit/offset information is not
included in the query.
"""
# The `do_offset` flag indicates whether we need to construct
# the SQL needed to use limit/offset w/Oracle.
do_offset = with_limits and (self.high_mark or self.low_mark)
# If no offsets, just return the result of the base class
# `as_sql`.
if not do_offset:
return super(OracleQuery, self).as_sql(with_limits=False)
# `get_columns` needs to be called before `get_ordering` to
# populate `_select_alias`.
self.pre_sql_setup()
out_cols = self.get_columns()
ordering = self.get_ordering()
# Getting the "ORDER BY" SQL for the ROW_NUMBER() result.
if ordering:
rn_orderby = ', '.join(ordering)
else:
# Oracle's ROW_NUMBER() function always requires an
# order-by clause. So we need to define a default
# order-by, since none was provided.
qn = self.quote_name_unless_alias
opts = self.model._meta
rn_orderby = '%s.%s' % (qn(opts.db_table), qn(opts.fields[0].db_column or opts.fields[0].column))
# Getting the selection SQL and the params, which has the `rn`
# extra selection SQL; we pop `rn` after this completes so we do
# not get the attribute on the returned models.
self.extra_select['rn'] = 'ROW_NUMBER() OVER (ORDER BY %s )' % rn_orderby
sql, params= super(OracleQuery, self).as_sql(with_limits=False)
self.extra_select.pop('rn')
# Constructing the result SQL, using the initial select SQL
# obtained above.
result = ['SELECT * FROM (%s)' % sql]
# Place WHERE condition on `rn` for the desired range.
result.append('WHERE rn > %d' % self.low_mark)
if self.high_mark:
result.append('AND rn <= %d' % self.high_mark)
# Returning the SQL w/params.
return ' '.join(result), params
from django.db import connection
class OracleQuerySet(DefaultQuerySet):
"The OracleQuerySet is overriden to use OracleQuery."
def __init__(self, model=None, query=None):
super(OracleQuerySet, self).__init__(model=model, query=query)
self.query = query or OracleQuery(self.model, connection)
return OracleQuerySet
def query_class(self, DefaultQueryClass):
return query.query_class(DefaultQueryClass, Database)
def quote_name(self, name):
# SQL92 requires delimited (quoted) names to be case-sensitive. When

130
django/db/backends/oracle/query.py Normal file
View File

@ -0,0 +1,130 @@
"""
Custom Query class for this backend (a derivative of
django.db.models.sql.query.Query).
"""
import datetime
from django.db.backends import util
# Cache. Maps default query class to new Oracle query class.
_classes = {}
def query_class(QueryClass, Database):
"""
Returns a custom djang.db.models.sql.query.Query subclass that is
appropraite for Oracle.
The 'Database' module (cx_Oracle) is passed in here so that all the setup
required to import it only needs to be done by the calling module.
"""
global _classes
try:
return _classes[QueryClass]
except KeyError:
pass
class OracleQuery(QueryClass):
def resolve_columns(self, row, fields=()):
from django.db.models.fields import DateField, DateTimeField, \
TimeField, BooleanField, NullBooleanField, DecimalField, Field
values = []
for value, field in map(None, row, fields):
if isinstance(value, Database.LOB):
value = value.read()
# Oracle stores empty strings as null. We need to undo this in
# order to adhere to the Django convention of using the empty
# string instead of null, but only if the field accepts the
# empty string.
if value is None and isinstance(field, Field) and field.empty_strings_allowed:
value = u''
# Convert 1 or 0 to True or False
elif value in (1, 0) and isinstance(field, (BooleanField, NullBooleanField)):
value = bool(value)
# Convert floats to decimals
elif value is not None and isinstance(field, DecimalField):
value = util.typecast_decimal(field.format_number(value))
# cx_Oracle always returns datetime.datetime objects for
# DATE and TIMESTAMP columns, but Django wants to see a
# python datetime.date, .time, or .datetime. We use the type
# of the Field to determine which to cast to, but it's not
# always available.
# As a workaround, we cast to date if all the time-related
# values are 0, or to time if the date is 1/1/1900.
# This could be cleaned a bit by adding a method to the Field
# classes to normalize values from the database (the to_python
# method is used for validation and isn't what we want here).
elif isinstance(value, Database.Timestamp):
# In Python 2.3, the cx_Oracle driver returns its own
# Timestamp object that we must convert to a datetime class.
if not isinstance(value, datetime.datetime):
value = datetime.datetime(value.year, value.month, value.day, value.hour,
value.minute, value.second, value.fsecond)
if isinstance(field, DateTimeField):
pass # DateTimeField subclasses DateField so must be checked first.
elif isinstance(field, DateField):
value = value.date()
elif isinstance(field, TimeField) or (value.year == 1900 and value.month == value.day == 1):
value = value.time()
elif value.hour == value.minute == value.second == value.microsecond == 0:
value = value.date()
values.append(value)
return values
def as_sql(self, with_limits=True):
"""
Creates the SQL for this query. Returns the SQL string and list
of parameters. This is overriden from the original Query class
to accommodate Oracle's limit/offset SQL.
If 'with_limits' is False, any limit/offset information is not
included in the query.
"""
# The `do_offset` flag indicates whether we need to construct
# the SQL needed to use limit/offset w/Oracle.
do_offset = with_limits and (self.high_mark or self.low_mark)
# If no offsets, just return the result of the base class
# `as_sql`.
if not do_offset:
return super(OracleQuery, self).as_sql(with_limits=False)
# `get_columns` needs to be called before `get_ordering` to
# populate `_select_alias`.
self.pre_sql_setup()
out_cols = self.get_columns()
ordering = self.get_ordering()
# Getting the "ORDER BY" SQL for the ROW_NUMBER() result.
if ordering:
rn_orderby = ', '.join(ordering)
else:
# Oracle's ROW_NUMBER() function always requires an
# order-by clause. So we need to define a default
# order-by, since none was provided.
qn = self.quote_name_unless_alias
opts = self.model._meta
rn_orderby = '%s.%s' % (qn(opts.db_table), qn(opts.fields[0].db_column or opts.fields[0].column))
# Getting the selection SQL and the params, which has the `rn`
# extra selection SQL; we pop `rn` after this completes so we do
# not get the attribute on the returned models.
self.extra_select['rn'] = 'ROW_NUMBER() OVER (ORDER BY %s )' % rn_orderby
sql, params= super(OracleQuery, self).as_sql(with_limits=False)
self.extra_select.pop('rn')
# Constructing the result SQL, using the initial select SQL
# obtained above.
result = ['SELECT * FROM (%s)' % sql]
# Place WHERE condition on `rn` for the desired range.
result.append('WHERE rn > %d' % self.low_mark)
if self.high_mark:
result.append('AND rn <= %d' % self.high_mark)
# Returning the SQL w/params.
return ' '.join(result), params
_classes[QueryClass] = OracleQuery
return OracleQuery