361 lines
14 KiB
Python
361 lines
14 KiB
Python
import datetime
|
|
import decimal
|
|
import uuid
|
|
from functools import lru_cache
|
|
from itertools import chain
|
|
|
|
from django.conf import settings
|
|
from django.core.exceptions import FieldError
|
|
from django.db import DatabaseError, NotSupportedError, models
|
|
from django.db.backends.base.operations import BaseDatabaseOperations
|
|
from django.db.models.expressions import Col
|
|
from django.utils import timezone
|
|
from django.utils.dateparse import parse_date, parse_datetime, parse_time
|
|
from django.utils.duration import duration_microseconds
|
|
from django.utils.functional import cached_property
|
|
|
|
|
|
class DatabaseOperations(BaseDatabaseOperations):
|
|
cast_char_field_without_max_length = 'text'
|
|
cast_data_types = {
|
|
'DateField': 'TEXT',
|
|
'DateTimeField': 'TEXT',
|
|
}
|
|
explain_prefix = 'EXPLAIN QUERY PLAN'
|
|
|
|
def bulk_batch_size(self, fields, objs):
|
|
"""
|
|
SQLite has a compile-time default (SQLITE_LIMIT_VARIABLE_NUMBER) of
|
|
999 variables per query.
|
|
|
|
If there's only a single field to insert, the limit is 500
|
|
(SQLITE_MAX_COMPOUND_SELECT).
|
|
"""
|
|
if len(fields) == 1:
|
|
return 500
|
|
elif len(fields) > 1:
|
|
return self.connection.features.max_query_params // len(fields)
|
|
else:
|
|
return len(objs)
|
|
|
|
def check_expression_support(self, expression):
|
|
bad_fields = (models.DateField, models.DateTimeField, models.TimeField)
|
|
bad_aggregates = (models.Sum, models.Avg, models.Variance, models.StdDev)
|
|
if isinstance(expression, bad_aggregates):
|
|
for expr in expression.get_source_expressions():
|
|
try:
|
|
output_field = expr.output_field
|
|
except (AttributeError, FieldError):
|
|
# Not every subexpression has an output_field which is fine
|
|
# to ignore.
|
|
pass
|
|
else:
|
|
if isinstance(output_field, bad_fields):
|
|
raise NotSupportedError(
|
|
'You cannot use Sum, Avg, StdDev, and Variance '
|
|
'aggregations on date/time fields in sqlite3 '
|
|
'since date/time is saved as text.'
|
|
)
|
|
if (
|
|
isinstance(expression, models.Aggregate) and
|
|
expression.distinct and
|
|
len(expression.source_expressions) > 1
|
|
):
|
|
raise NotSupportedError(
|
|
"SQLite doesn't support DISTINCT on aggregate functions "
|
|
"accepting multiple arguments."
|
|
)
|
|
|
|
def date_extract_sql(self, lookup_type, field_name):
|
|
"""
|
|
Support EXTRACT with a user-defined function django_date_extract()
|
|
that's registered in connect(). Use single quotes because this is a
|
|
string and could otherwise cause a collision with a field name.
|
|
"""
|
|
return "django_date_extract('%s', %s)" % (lookup_type.lower(), field_name)
|
|
|
|
def date_interval_sql(self, timedelta):
|
|
return str(duration_microseconds(timedelta))
|
|
|
|
def format_for_duration_arithmetic(self, sql):
|
|
"""Do nothing since formatting is handled in the custom function."""
|
|
return sql
|
|
|
|
def date_trunc_sql(self, lookup_type, field_name):
|
|
return "django_date_trunc('%s', %s)" % (lookup_type.lower(), field_name)
|
|
|
|
def time_trunc_sql(self, lookup_type, field_name):
|
|
return "django_time_trunc('%s', %s)" % (lookup_type.lower(), field_name)
|
|
|
|
def _convert_tznames_to_sql(self, tzname):
|
|
if settings.USE_TZ:
|
|
return "'%s'" % tzname, "'%s'" % self.connection.timezone_name
|
|
return 'NULL', 'NULL'
|
|
|
|
def datetime_cast_date_sql(self, field_name, tzname):
|
|
return 'django_datetime_cast_date(%s, %s, %s)' % (
|
|
field_name, *self._convert_tznames_to_sql(tzname),
|
|
)
|
|
|
|
def datetime_cast_time_sql(self, field_name, tzname):
|
|
return 'django_datetime_cast_time(%s, %s, %s)' % (
|
|
field_name, *self._convert_tznames_to_sql(tzname),
|
|
)
|
|
|
|
def datetime_extract_sql(self, lookup_type, field_name, tzname):
|
|
return "django_datetime_extract('%s', %s, %s, %s)" % (
|
|
lookup_type.lower(), field_name, *self._convert_tznames_to_sql(tzname),
|
|
)
|
|
|
|
def datetime_trunc_sql(self, lookup_type, field_name, tzname):
|
|
return "django_datetime_trunc('%s', %s, %s, %s)" % (
|
|
lookup_type.lower(), field_name, *self._convert_tznames_to_sql(tzname),
|
|
)
|
|
|
|
def time_extract_sql(self, lookup_type, field_name):
|
|
return "django_time_extract('%s', %s)" % (lookup_type.lower(), field_name)
|
|
|
|
def pk_default_value(self):
|
|
return "NULL"
|
|
|
|
def _quote_params_for_last_executed_query(self, params):
|
|
"""
|
|
Only for last_executed_query! Don't use this to execute SQL queries!
|
|
"""
|
|
# This function is limited both by SQLITE_LIMIT_VARIABLE_NUMBER (the
|
|
# number of parameters, default = 999) and SQLITE_MAX_COLUMN (the
|
|
# number of return values, default = 2000). Since Python's sqlite3
|
|
# module doesn't expose the get_limit() C API, assume the default
|
|
# limits are in effect and split the work in batches if needed.
|
|
BATCH_SIZE = 999
|
|
if len(params) > BATCH_SIZE:
|
|
results = ()
|
|
for index in range(0, len(params), BATCH_SIZE):
|
|
chunk = params[index:index + BATCH_SIZE]
|
|
results += self._quote_params_for_last_executed_query(chunk)
|
|
return results
|
|
|
|
sql = 'SELECT ' + ', '.join(['QUOTE(?)'] * len(params))
|
|
# Bypass Django's wrappers and use the underlying sqlite3 connection
|
|
# to avoid logging this query - it would trigger infinite recursion.
|
|
cursor = self.connection.connection.cursor()
|
|
# Native sqlite3 cursors cannot be used as context managers.
|
|
try:
|
|
return cursor.execute(sql, params).fetchone()
|
|
finally:
|
|
cursor.close()
|
|
|
|
def last_executed_query(self, cursor, sql, params):
|
|
# Python substitutes parameters in Modules/_sqlite/cursor.c with:
|
|
# pysqlite_statement_bind_parameters(self->statement, parameters, allow_8bit_chars);
|
|
# Unfortunately there is no way to reach self->statement from Python,
|
|
# so we quote and substitute parameters manually.
|
|
if params:
|
|
if isinstance(params, (list, tuple)):
|
|
params = self._quote_params_for_last_executed_query(params)
|
|
else:
|
|
values = tuple(params.values())
|
|
values = self._quote_params_for_last_executed_query(values)
|
|
params = dict(zip(params, values))
|
|
return sql % params
|
|
# For consistency with SQLiteCursorWrapper.execute(), just return sql
|
|
# when there are no parameters. See #13648 and #17158.
|
|
else:
|
|
return sql
|
|
|
|
def quote_name(self, name):
|
|
if name.startswith('"') and name.endswith('"'):
|
|
return name # Quoting once is enough.
|
|
return '"%s"' % name
|
|
|
|
def no_limit_value(self):
|
|
return -1
|
|
|
|
def __references_graph(self, table_name):
|
|
query = """
|
|
WITH tables AS (
|
|
SELECT %s name
|
|
UNION
|
|
SELECT sqlite_master.name
|
|
FROM sqlite_master
|
|
JOIN tables ON (sql REGEXP %s || tables.name || %s)
|
|
) SELECT name FROM tables;
|
|
"""
|
|
params = (
|
|
table_name,
|
|
r'(?i)\s+references\s+("|\')?',
|
|
r'("|\')?\s*\(',
|
|
)
|
|
with self.connection.cursor() as cursor:
|
|
results = cursor.execute(query, params)
|
|
return [row[0] for row in results.fetchall()]
|
|
|
|
@cached_property
|
|
def _references_graph(self):
|
|
# 512 is large enough to fit the ~330 tables (as of this writing) in
|
|
# Django's test suite.
|
|
return lru_cache(maxsize=512)(self.__references_graph)
|
|
|
|
def sql_flush(self, style, tables, *, reset_sequences=False, allow_cascade=False):
|
|
if tables and allow_cascade:
|
|
# Simulate TRUNCATE CASCADE by recursively collecting the tables
|
|
# referencing the tables to be flushed.
|
|
tables = set(chain.from_iterable(self._references_graph(table) for table in tables))
|
|
sql = ['%s %s %s;' % (
|
|
style.SQL_KEYWORD('DELETE'),
|
|
style.SQL_KEYWORD('FROM'),
|
|
style.SQL_FIELD(self.quote_name(table))
|
|
) for table in tables]
|
|
if reset_sequences:
|
|
sequences = [{'table': table} for table in tables]
|
|
sql.extend(self.sequence_reset_by_name_sql(style, sequences))
|
|
return sql
|
|
|
|
def sequence_reset_by_name_sql(self, style, sequences):
|
|
if not sequences:
|
|
return []
|
|
return [
|
|
'%s %s %s %s = 0 %s %s %s (%s);' % (
|
|
style.SQL_KEYWORD('UPDATE'),
|
|
style.SQL_TABLE(self.quote_name('sqlite_sequence')),
|
|
style.SQL_KEYWORD('SET'),
|
|
style.SQL_FIELD(self.quote_name('seq')),
|
|
style.SQL_KEYWORD('WHERE'),
|
|
style.SQL_FIELD(self.quote_name('name')),
|
|
style.SQL_KEYWORD('IN'),
|
|
', '.join([
|
|
"'%s'" % sequence_info['table'] for sequence_info in sequences
|
|
]),
|
|
),
|
|
]
|
|
|
|
def adapt_datetimefield_value(self, value):
|
|
if value is None:
|
|
return None
|
|
|
|
# Expression values are adapted by the database.
|
|
if hasattr(value, 'resolve_expression'):
|
|
return value
|
|
|
|
# SQLite doesn't support tz-aware datetimes
|
|
if timezone.is_aware(value):
|
|
if settings.USE_TZ:
|
|
value = timezone.make_naive(value, self.connection.timezone)
|
|
else:
|
|
raise ValueError("SQLite backend does not support timezone-aware datetimes when USE_TZ is False.")
|
|
|
|
return str(value)
|
|
|
|
def adapt_timefield_value(self, value):
|
|
if value is None:
|
|
return None
|
|
|
|
# Expression values are adapted by the database.
|
|
if hasattr(value, 'resolve_expression'):
|
|
return value
|
|
|
|
# SQLite doesn't support tz-aware datetimes
|
|
if timezone.is_aware(value):
|
|
raise ValueError("SQLite backend does not support timezone-aware times.")
|
|
|
|
return str(value)
|
|
|
|
def get_db_converters(self, expression):
|
|
converters = super().get_db_converters(expression)
|
|
internal_type = expression.output_field.get_internal_type()
|
|
if internal_type == 'DateTimeField':
|
|
converters.append(self.convert_datetimefield_value)
|
|
elif internal_type == 'DateField':
|
|
converters.append(self.convert_datefield_value)
|
|
elif internal_type == 'TimeField':
|
|
converters.append(self.convert_timefield_value)
|
|
elif internal_type == 'DecimalField':
|
|
converters.append(self.get_decimalfield_converter(expression))
|
|
elif internal_type == 'UUIDField':
|
|
converters.append(self.convert_uuidfield_value)
|
|
elif internal_type in ('NullBooleanField', 'BooleanField'):
|
|
converters.append(self.convert_booleanfield_value)
|
|
return converters
|
|
|
|
def convert_datetimefield_value(self, value, expression, connection):
|
|
if value is not None:
|
|
if not isinstance(value, datetime.datetime):
|
|
value = parse_datetime(value)
|
|
if settings.USE_TZ and not timezone.is_aware(value):
|
|
value = timezone.make_aware(value, self.connection.timezone)
|
|
return value
|
|
|
|
def convert_datefield_value(self, value, expression, connection):
|
|
if value is not None:
|
|
if not isinstance(value, datetime.date):
|
|
value = parse_date(value)
|
|
return value
|
|
|
|
def convert_timefield_value(self, value, expression, connection):
|
|
if value is not None:
|
|
if not isinstance(value, datetime.time):
|
|
value = parse_time(value)
|
|
return value
|
|
|
|
def get_decimalfield_converter(self, expression):
|
|
# SQLite stores only 15 significant digits. Digits coming from
|
|
# float inaccuracy must be removed.
|
|
create_decimal = decimal.Context(prec=15).create_decimal_from_float
|
|
if isinstance(expression, Col):
|
|
quantize_value = decimal.Decimal(1).scaleb(-expression.output_field.decimal_places)
|
|
|
|
def converter(value, expression, connection):
|
|
if value is not None:
|
|
return create_decimal(value).quantize(quantize_value, context=expression.output_field.context)
|
|
else:
|
|
def converter(value, expression, connection):
|
|
if value is not None:
|
|
return create_decimal(value)
|
|
return converter
|
|
|
|
def convert_uuidfield_value(self, value, expression, connection):
|
|
if value is not None:
|
|
value = uuid.UUID(value)
|
|
return value
|
|
|
|
def convert_booleanfield_value(self, value, expression, connection):
|
|
return bool(value) if value in (1, 0) else value
|
|
|
|
def bulk_insert_sql(self, fields, placeholder_rows):
|
|
return " UNION ALL ".join(
|
|
"SELECT %s" % ", ".join(row)
|
|
for row in placeholder_rows
|
|
)
|
|
|
|
def combine_expression(self, connector, sub_expressions):
|
|
# SQLite doesn't have a ^ operator, so use the user-defined POWER
|
|
# function that's registered in connect().
|
|
if connector == '^':
|
|
return 'POWER(%s)' % ','.join(sub_expressions)
|
|
elif connector == '#':
|
|
return 'BITXOR(%s)' % ','.join(sub_expressions)
|
|
return super().combine_expression(connector, sub_expressions)
|
|
|
|
def combine_duration_expression(self, connector, sub_expressions):
|
|
if connector not in ['+', '-']:
|
|
raise DatabaseError('Invalid connector for timedelta: %s.' % connector)
|
|
fn_params = ["'%s'" % connector] + sub_expressions
|
|
if len(fn_params) > 3:
|
|
raise ValueError('Too many params for timedelta operations.')
|
|
return "django_format_dtdelta(%s)" % ', '.join(fn_params)
|
|
|
|
def integer_field_range(self, internal_type):
|
|
# SQLite doesn't enforce any integer constraints
|
|
return (None, None)
|
|
|
|
def subtract_temporals(self, internal_type, lhs, rhs):
|
|
lhs_sql, lhs_params = lhs
|
|
rhs_sql, rhs_params = rhs
|
|
params = (*lhs_params, *rhs_params)
|
|
if internal_type == 'TimeField':
|
|
return 'django_time_diff(%s, %s)' % (lhs_sql, rhs_sql), params
|
|
return 'django_timestamp_diff(%s, %s)' % (lhs_sql, rhs_sql), params
|
|
|
|
def insert_statement(self, ignore_conflicts=False):
|
|
return 'INSERT OR IGNORE INTO' if ignore_conflicts else super().insert_statement(ignore_conflicts)
|