UnisKB/apps/common/db/compiler.py

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# coding=utf-8
"""
@project: maxkb
@Author
@file compiler.py
@date2023/10/7 10:53
@desc:
"""
from django.core.exceptions import EmptyResultSet, FullResultSet
from django.db import NotSupportedError
from django.db.models.sql.compiler import SQLCompiler
from django.db.transaction import TransactionManagementError
class AppSQLCompiler(SQLCompiler):
def __init__(self, query, connection, using, elide_empty=True, field_replace_dict=None):
super().__init__(query, connection, using, elide_empty)
if field_replace_dict is None:
field_replace_dict = {}
self.field_replace_dict = field_replace_dict
def get_query_str(self, with_limits=True, with_table_name=False, with_col_aliases=False):
refcounts_before = self.query.alias_refcount.copy()
try:
combinator = self.query.combinator
extra_select, order_by, group_by = self.pre_sql_setup(
with_col_aliases=with_col_aliases or bool(combinator),
)
for_update_part = None
# Is a LIMIT/OFFSET clause needed?
with_limit_offset = with_limits and self.query.is_sliced
combinator = self.query.combinator
features = self.connection.features
if combinator:
if not getattr(features, "supports_select_{}".format(combinator)):
raise NotSupportedError(
"{} is not supported on this database backend.".format(
combinator
)
)
result, params = self.get_combinator_sql(
combinator, self.query.combinator_all
)
elif self.qualify:
result, params = self.get_qualify_sql()
order_by = None
else:
distinct_fields, distinct_params = self.get_distinct()
# This must come after 'select', 'ordering', and 'distinct'
# (see docstring of get_from_clause() for details).
from_, f_params = self.get_from_clause()
try:
where, w_params = (
self.compile(self.where) if self.where is not None else ("", [])
)
except EmptyResultSet:
if self.elide_empty:
raise
# Use a predicate that's always False.
where, w_params = "0 = 1", []
except FullResultSet:
where, w_params = "", []
try:
having, h_params = (
self.compile(self.having)
if self.having is not None
else ("", [])
)
except FullResultSet:
having, h_params = "", []
result = []
params = []
if self.query.distinct:
distinct_result, distinct_params = self.connection.ops.distinct_sql(
distinct_fields,
distinct_params,
)
result += distinct_result
params += distinct_params
out_cols = []
for _, (s_sql, s_params), alias in self.select + extra_select:
if alias:
s_sql = "%s AS %s" % (
s_sql,
self.connection.ops.quote_name(alias),
)
params.extend(s_params)
out_cols.append(s_sql)
params.extend(f_params)
if self.query.select_for_update and features.has_select_for_update:
if (
self.connection.get_autocommit()
# Don't raise an exception when database doesn't
# support transactions, as it's a noop.
and features.supports_transactions
):
raise TransactionManagementError(
"select_for_update cannot be used outside of a transaction."
)
if (
with_limit_offset
and not features.supports_select_for_update_with_limit
):
raise NotSupportedError(
"LIMIT/OFFSET is not supported with "
"select_for_update on this database backend."
)
nowait = self.query.select_for_update_nowait
skip_locked = self.query.select_for_update_skip_locked
of = self.query.select_for_update_of
no_key = self.query.select_for_no_key_update
# If it's a NOWAIT/SKIP LOCKED/OF/NO KEY query but the
# backend doesn't support it, raise NotSupportedError to
# prevent a possible deadlock.
if nowait and not features.has_select_for_update_nowait:
raise NotSupportedError(
"NOWAIT is not supported on this database backend."
)
elif skip_locked and not features.has_select_for_update_skip_locked:
raise NotSupportedError(
"SKIP LOCKED is not supported on this database backend."
)
elif of and not features.has_select_for_update_of:
raise NotSupportedError(
"FOR UPDATE OF is not supported on this database backend."
)
elif no_key and not features.has_select_for_no_key_update:
raise NotSupportedError(
"FOR NO KEY UPDATE is not supported on this "
"database backend."
)
for_update_part = self.connection.ops.for_update_sql(
nowait=nowait,
skip_locked=skip_locked,
of=self.get_select_for_update_of_arguments(),
no_key=no_key,
)
if for_update_part and features.for_update_after_from:
result.append(for_update_part)
if where:
result.append("WHERE %s" % where)
params.extend(w_params)
grouping = []
for g_sql, g_params in group_by:
grouping.append(g_sql)
params.extend(g_params)
if grouping:
if distinct_fields:
raise NotImplementedError(
"annotate() + distinct(fields) is not implemented."
)
order_by = order_by or self.connection.ops.force_no_ordering()
result.append("GROUP BY %s" % ", ".join(grouping))
if self._meta_ordering:
order_by = None
if having:
result.append("HAVING %s" % having)
params.extend(h_params)
if self.query.explain_info:
result.insert(
0,
self.connection.ops.explain_query_prefix(
self.query.explain_info.format,
**self.query.explain_info.options,
),
)
if order_by:
ordering = []
for _, (o_sql, o_params, _) in order_by:
ordering.append(o_sql)
params.extend(o_params)
order_by_sql = "ORDER BY %s" % ", ".join(ordering)
if combinator and features.requires_compound_order_by_subquery:
result = ["SELECT * FROM (", *result, ")", order_by_sql]
else:
result.append(order_by_sql)
if with_limit_offset:
result.append(
self.connection.ops.limit_offset_sql(
self.query.low_mark, self.query.high_mark
)
)
if for_update_part and not features.for_update_after_from:
result.append(for_update_part)
from_, f_params = self.get_from_clause()
sql = " ".join(result)
if not with_table_name:
for table_name in from_:
sql = sql.replace(table_name + ".", "")
for key in self.field_replace_dict.keys():
value = self.field_replace_dict.get(key)
sql = sql.replace(key, value)
return sql, tuple(params)
finally:
# Finally do cleanup - get rid of the joins we created above.
self.query.reset_refcounts(refcounts_before)
def as_sql(self, with_limits=True, with_col_aliases=False, select_string=None):
if select_string is None:
return super().as_sql(with_limits, with_col_aliases)
else:
sql, params = self.get_query_str(with_table_name=False)
return (select_string + " " + sql), params