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queryset-refactor: The Oracle changes necessary for [7426]. I can't test these
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
parent
1add6fb366
commit
f2b64c0c4e
@ -49,7 +49,7 @@ class BaseDatabaseFeatures(object):
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supports_constraints = True
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supports_tablespaces = False
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uses_case_insensitive_names = False
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uses_custom_queryset = False
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uses_custom_query_class = False
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empty_fetchmany_value = []
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class BaseDatabaseOperations(object):
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@ -199,11 +199,11 @@ class BaseDatabaseOperations(object):
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"""
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return 'DEFAULT'
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def query_set_class(self, DefaultQuerySet):
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def query_class(self, DefaultQueryClass):
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"""
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Given the default QuerySet class, returns a custom QuerySet class
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to use for this backend. Returns None if a custom QuerySet isn't used.
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See also BaseDatabaseFeatures.uses_custom_queryset, which regulates
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See also BaseDatabaseFeatures.uses_custom_query_class, which regulates
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whether this method is called at all.
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"""
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return None
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@ -4,10 +4,10 @@ Oracle database backend for Django.
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Requires cx_Oracle: http://www.python.net/crew/atuining/cx_Oracle/
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"""
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import datetime
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import os
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from django.db.backends import BaseDatabaseWrapper, BaseDatabaseFeatures, BaseDatabaseOperations, util
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from django.db.backends.oracle import query
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from django.utils.datastructures import SortedDict
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from django.utils.encoding import smart_str, force_unicode
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@ -30,7 +30,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
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needs_upper_for_iops = True
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supports_tablespaces = True
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uses_case_insensitive_names = True
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uses_custom_queryset = True
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uses_custom_query_class = True
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class DatabaseOperations(BaseDatabaseOperations):
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def autoinc_sql(self, table, column):
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@ -99,118 +99,8 @@ class DatabaseOperations(BaseDatabaseOperations):
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def max_name_length(self):
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return 30
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def query_set_class(self, DefaultQuerySet):
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# Getting the base default `Query` object.
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DefaultQuery = DefaultQuerySet().query.__class__
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class OracleQuery(DefaultQuery):
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def resolve_columns(self, row, fields=()):
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from django.db.models.fields import DateField, DateTimeField, \
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TimeField, BooleanField, NullBooleanField, DecimalField, Field
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values = []
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for value, field in map(None, row, fields):
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if isinstance(value, Database.LOB):
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value = value.read()
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# Oracle stores empty strings as null. We need to undo this in
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# order to adhere to the Django convention of using the empty
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# string instead of null, but only if the field accepts the
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# empty string.
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if value is None and isinstance(field, Field) and field.empty_strings_allowed:
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value = u''
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# Convert 1 or 0 to True or False
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elif value in (1, 0) and isinstance(field, (BooleanField, NullBooleanField)):
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value = bool(value)
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# Convert floats to decimals
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elif value is not None and isinstance(field, DecimalField):
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value = util.typecast_decimal(field.format_number(value))
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# cx_Oracle always returns datetime.datetime objects for
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# DATE and TIMESTAMP columns, but Django wants to see a
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# python datetime.date, .time, or .datetime. We use the type
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# of the Field to determine which to cast to, but it's not
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# always available.
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# As a workaround, we cast to date if all the time-related
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# values are 0, or to time if the date is 1/1/1900.
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# This could be cleaned a bit by adding a method to the Field
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# classes to normalize values from the database (the to_python
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# method is used for validation and isn't what we want here).
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elif isinstance(value, Database.Timestamp):
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# In Python 2.3, the cx_Oracle driver returns its own
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# Timestamp object that we must convert to a datetime class.
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if not isinstance(value, datetime.datetime):
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value = datetime.datetime(value.year, value.month, value.day, value.hour,
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value.minute, value.second, value.fsecond)
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if isinstance(field, DateTimeField):
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pass # DateTimeField subclasses DateField so must be checked first.
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elif isinstance(field, DateField):
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value = value.date()
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elif isinstance(field, TimeField) or (value.year == 1900 and value.month == value.day == 1):
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value = value.time()
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elif value.hour == value.minute == value.second == value.microsecond == 0:
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value = value.date()
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values.append(value)
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return values
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def as_sql(self, with_limits=True):
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"""
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Creates the SQL for this query. Returns the SQL string and list
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of parameters. This is overriden from the original Query class
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to accommodate Oracle's limit/offset SQL.
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If 'with_limits' is False, any limit/offset information is not
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included in the query.
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"""
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# The `do_offset` flag indicates whether we need to construct
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# the SQL needed to use limit/offset w/Oracle.
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do_offset = with_limits and (self.high_mark or self.low_mark)
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# If no offsets, just return the result of the base class
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# `as_sql`.
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if not do_offset:
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return super(OracleQuery, self).as_sql(with_limits=False)
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# `get_columns` needs to be called before `get_ordering` to
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# populate `_select_alias`.
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self.pre_sql_setup()
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out_cols = self.get_columns()
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ordering = self.get_ordering()
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# Getting the "ORDER BY" SQL for the ROW_NUMBER() result.
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if ordering:
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rn_orderby = ', '.join(ordering)
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else:
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# Oracle's ROW_NUMBER() function always requires an
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# order-by clause. So we need to define a default
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# order-by, since none was provided.
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qn = self.quote_name_unless_alias
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opts = self.model._meta
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rn_orderby = '%s.%s' % (qn(opts.db_table), qn(opts.fields[0].db_column or opts.fields[0].column))
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# Getting the selection SQL and the params, which has the `rn`
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# extra selection SQL; we pop `rn` after this completes so we do
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# not get the attribute on the returned models.
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self.extra_select['rn'] = 'ROW_NUMBER() OVER (ORDER BY %s )' % rn_orderby
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sql, params= super(OracleQuery, self).as_sql(with_limits=False)
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self.extra_select.pop('rn')
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# Constructing the result SQL, using the initial select SQL
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# obtained above.
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result = ['SELECT * FROM (%s)' % sql]
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# Place WHERE condition on `rn` for the desired range.
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result.append('WHERE rn > %d' % self.low_mark)
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if self.high_mark:
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result.append('AND rn <= %d' % self.high_mark)
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# Returning the SQL w/params.
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return ' '.join(result), params
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from django.db import connection
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class OracleQuerySet(DefaultQuerySet):
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"The OracleQuerySet is overriden to use OracleQuery."
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def __init__(self, model=None, query=None):
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super(OracleQuerySet, self).__init__(model=model, query=query)
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self.query = query or OracleQuery(self.model, connection)
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return OracleQuerySet
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def query_class(self, DefaultQueryClass):
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return query.query_class(DefaultQueryClass, Database)
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def quote_name(self, name):
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# SQL92 requires delimited (quoted) names to be case-sensitive. When
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130
django/db/backends/oracle/query.py
Normal file
130
django/db/backends/oracle/query.py
Normal file
@ -0,0 +1,130 @@
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"""
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Custom Query class for this backend (a derivative of
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django.db.models.sql.query.Query).
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"""
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import datetime
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from django.db.backends import util
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# Cache. Maps default query class to new Oracle query class.
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_classes = {}
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def query_class(QueryClass, Database):
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"""
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Returns a custom djang.db.models.sql.query.Query subclass that is
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appropraite for Oracle.
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The 'Database' module (cx_Oracle) is passed in here so that all the setup
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required to import it only needs to be done by the calling module.
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"""
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global _classes
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try:
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return _classes[QueryClass]
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except KeyError:
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pass
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class OracleQuery(QueryClass):
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def resolve_columns(self, row, fields=()):
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from django.db.models.fields import DateField, DateTimeField, \
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TimeField, BooleanField, NullBooleanField, DecimalField, Field
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values = []
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for value, field in map(None, row, fields):
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if isinstance(value, Database.LOB):
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value = value.read()
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# Oracle stores empty strings as null. We need to undo this in
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# order to adhere to the Django convention of using the empty
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# string instead of null, but only if the field accepts the
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# empty string.
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if value is None and isinstance(field, Field) and field.empty_strings_allowed:
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value = u''
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# Convert 1 or 0 to True or False
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elif value in (1, 0) and isinstance(field, (BooleanField, NullBooleanField)):
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value = bool(value)
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# Convert floats to decimals
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elif value is not None and isinstance(field, DecimalField):
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value = util.typecast_decimal(field.format_number(value))
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# cx_Oracle always returns datetime.datetime objects for
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# DATE and TIMESTAMP columns, but Django wants to see a
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# python datetime.date, .time, or .datetime. We use the type
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# of the Field to determine which to cast to, but it's not
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# always available.
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# As a workaround, we cast to date if all the time-related
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# values are 0, or to time if the date is 1/1/1900.
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# This could be cleaned a bit by adding a method to the Field
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# classes to normalize values from the database (the to_python
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# method is used for validation and isn't what we want here).
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elif isinstance(value, Database.Timestamp):
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# In Python 2.3, the cx_Oracle driver returns its own
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# Timestamp object that we must convert to a datetime class.
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if not isinstance(value, datetime.datetime):
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value = datetime.datetime(value.year, value.month, value.day, value.hour,
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value.minute, value.second, value.fsecond)
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if isinstance(field, DateTimeField):
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pass # DateTimeField subclasses DateField so must be checked first.
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elif isinstance(field, DateField):
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value = value.date()
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elif isinstance(field, TimeField) or (value.year == 1900 and value.month == value.day == 1):
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value = value.time()
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elif value.hour == value.minute == value.second == value.microsecond == 0:
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value = value.date()
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values.append(value)
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return values
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def as_sql(self, with_limits=True):
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"""
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Creates the SQL for this query. Returns the SQL string and list
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of parameters. This is overriden from the original Query class
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to accommodate Oracle's limit/offset SQL.
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If 'with_limits' is False, any limit/offset information is not
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included in the query.
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"""
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# The `do_offset` flag indicates whether we need to construct
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# the SQL needed to use limit/offset w/Oracle.
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do_offset = with_limits and (self.high_mark or self.low_mark)
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# If no offsets, just return the result of the base class
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# `as_sql`.
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if not do_offset:
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return super(OracleQuery, self).as_sql(with_limits=False)
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# `get_columns` needs to be called before `get_ordering` to
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# populate `_select_alias`.
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self.pre_sql_setup()
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out_cols = self.get_columns()
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ordering = self.get_ordering()
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# Getting the "ORDER BY" SQL for the ROW_NUMBER() result.
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if ordering:
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rn_orderby = ', '.join(ordering)
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else:
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# Oracle's ROW_NUMBER() function always requires an
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# order-by clause. So we need to define a default
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# order-by, since none was provided.
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qn = self.quote_name_unless_alias
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opts = self.model._meta
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rn_orderby = '%s.%s' % (qn(opts.db_table), qn(opts.fields[0].db_column or opts.fields[0].column))
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# Getting the selection SQL and the params, which has the `rn`
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# extra selection SQL; we pop `rn` after this completes so we do
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# not get the attribute on the returned models.
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self.extra_select['rn'] = 'ROW_NUMBER() OVER (ORDER BY %s )' % rn_orderby
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sql, params= super(OracleQuery, self).as_sql(with_limits=False)
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self.extra_select.pop('rn')
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# Constructing the result SQL, using the initial select SQL
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# obtained above.
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result = ['SELECT * FROM (%s)' % sql]
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# Place WHERE condition on `rn` for the desired range.
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result.append('WHERE rn > %d' % self.low_mark)
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if self.high_mark:
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result.append('AND rn <= %d' % self.high_mark)
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# Returning the SQL w/params.
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return ' '.join(result), params
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_classes[QueryClass] = OracleQuery
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return OracleQuery
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