356 lines
13 KiB
Python
356 lines
13 KiB
Python
from psycopg2.extras import Inet
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from django.conf import settings
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from django.db.backends.base.operations import BaseDatabaseOperations
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from django.db.backends.utils import split_tzname_delta
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from django.db.models.constants import OnConflict
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class DatabaseOperations(BaseDatabaseOperations):
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cast_char_field_without_max_length = "varchar"
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explain_prefix = "EXPLAIN"
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explain_options = frozenset(
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[
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"ANALYZE",
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"BUFFERS",
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"COSTS",
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"SETTINGS",
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"SUMMARY",
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"TIMING",
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"VERBOSE",
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"WAL",
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]
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)
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cast_data_types = {
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"AutoField": "integer",
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"BigAutoField": "bigint",
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"SmallAutoField": "smallint",
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}
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def unification_cast_sql(self, output_field):
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internal_type = output_field.get_internal_type()
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if internal_type in (
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"GenericIPAddressField",
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"IPAddressField",
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"TimeField",
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"UUIDField",
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):
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# PostgreSQL will resolve a union as type 'text' if input types are
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# 'unknown'.
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# https://www.postgresql.org/docs/current/typeconv-union-case.html
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# These fields cannot be implicitly cast back in the default
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# PostgreSQL configuration so we need to explicitly cast them.
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# We must also remove components of the type within brackets:
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# varchar(255) -> varchar.
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return (
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"CAST(%%s AS %s)" % output_field.db_type(self.connection).split("(")[0]
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)
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return "%s"
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def date_extract_sql(self, lookup_type, sql, params):
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# https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
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extract_sql = f"EXTRACT(%s FROM {sql})"
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extract_param = lookup_type
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if lookup_type == "week_day":
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# For consistency across backends, we return Sunday=1, Saturday=7.
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extract_sql = f"EXTRACT(%s FROM {sql}) + 1"
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extract_param = "dow"
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elif lookup_type == "iso_week_day":
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extract_param = "isodow"
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elif lookup_type == "iso_year":
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extract_param = "isoyear"
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return extract_sql, (extract_param, *params)
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def date_trunc_sql(self, lookup_type, sql, params, tzname=None):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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# https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
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return f"DATE_TRUNC(%s, {sql})", (lookup_type, *params)
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def _prepare_tzname_delta(self, tzname):
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tzname, sign, offset = split_tzname_delta(tzname)
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if offset:
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sign = "-" if sign == "+" else "+"
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return f"{tzname}{sign}{offset}"
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return tzname
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def _convert_sql_to_tz(self, sql, params, tzname):
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if tzname and settings.USE_TZ:
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tzname_param = self._prepare_tzname_delta(tzname)
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return f"{sql} AT TIME ZONE %s", (*params, tzname_param)
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return sql, params
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def datetime_cast_date_sql(self, sql, params, tzname):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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return f"({sql})::date", params
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def datetime_cast_time_sql(self, sql, params, tzname):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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return f"({sql})::time", params
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def datetime_extract_sql(self, lookup_type, sql, params, tzname):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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if lookup_type == "second":
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# Truncate fractional seconds.
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return (
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f"EXTRACT(%s FROM DATE_TRUNC(%s, {sql}))",
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("second", "second", *params),
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)
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return self.date_extract_sql(lookup_type, sql, params)
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def datetime_trunc_sql(self, lookup_type, sql, params, tzname):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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# https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
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return f"DATE_TRUNC(%s, {sql})", (lookup_type, *params)
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def time_extract_sql(self, lookup_type, sql, params):
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if lookup_type == "second":
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# Truncate fractional seconds.
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return (
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f"EXTRACT(%s FROM DATE_TRUNC(%s, {sql}))",
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("second", "second", *params),
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)
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return self.date_extract_sql(lookup_type, sql, params)
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def time_trunc_sql(self, lookup_type, sql, params, tzname=None):
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sql, params = self._convert_sql_to_tz(sql, params, tzname)
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return f"DATE_TRUNC(%s, {sql})::time", (lookup_type, *params)
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def deferrable_sql(self):
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return " DEFERRABLE INITIALLY DEFERRED"
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def fetch_returned_insert_rows(self, cursor):
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"""
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Given a cursor object that has just performed an INSERT...RETURNING
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statement into a table, return the tuple of returned data.
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"""
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return cursor.fetchall()
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def lookup_cast(self, lookup_type, internal_type=None):
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lookup = "%s"
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# Cast text lookups to text to allow things like filter(x__contains=4)
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if lookup_type in (
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"iexact",
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"contains",
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"icontains",
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"startswith",
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"istartswith",
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"endswith",
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"iendswith",
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"regex",
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"iregex",
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):
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if internal_type in ("IPAddressField", "GenericIPAddressField"):
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lookup = "HOST(%s)"
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elif internal_type in ("CICharField", "CIEmailField", "CITextField"):
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lookup = "%s::citext"
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else:
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lookup = "%s::text"
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# Use UPPER(x) for case-insensitive lookups; it's faster.
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if lookup_type in ("iexact", "icontains", "istartswith", "iendswith"):
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lookup = "UPPER(%s)" % lookup
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return lookup
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def no_limit_value(self):
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return None
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def prepare_sql_script(self, sql):
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return [sql]
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def quote_name(self, name):
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if name.startswith('"') and name.endswith('"'):
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return name # Quoting once is enough.
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return '"%s"' % name
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def set_time_zone_sql(self):
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return "SET TIME ZONE %s"
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def sql_flush(self, style, tables, *, reset_sequences=False, allow_cascade=False):
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if not tables:
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return []
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# Perform a single SQL 'TRUNCATE x, y, z...;' statement. It allows us
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# to truncate tables referenced by a foreign key in any other table.
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sql_parts = [
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style.SQL_KEYWORD("TRUNCATE"),
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", ".join(style.SQL_FIELD(self.quote_name(table)) for table in tables),
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]
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if reset_sequences:
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sql_parts.append(style.SQL_KEYWORD("RESTART IDENTITY"))
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if allow_cascade:
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sql_parts.append(style.SQL_KEYWORD("CASCADE"))
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return ["%s;" % " ".join(sql_parts)]
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def sequence_reset_by_name_sql(self, style, sequences):
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# 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
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# to reset sequence indices
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sql = []
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for sequence_info in sequences:
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table_name = sequence_info["table"]
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# 'id' will be the case if it's an m2m using an autogenerated
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# intermediate table (see BaseDatabaseIntrospection.sequence_list).
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column_name = sequence_info["column"] or "id"
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sql.append(
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"%s setval(pg_get_serial_sequence('%s','%s'), 1, false);"
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% (
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style.SQL_KEYWORD("SELECT"),
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style.SQL_TABLE(self.quote_name(table_name)),
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style.SQL_FIELD(column_name),
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)
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)
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return sql
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def tablespace_sql(self, tablespace, inline=False):
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if inline:
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return "USING INDEX TABLESPACE %s" % self.quote_name(tablespace)
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else:
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return "TABLESPACE %s" % self.quote_name(tablespace)
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def sequence_reset_sql(self, style, model_list):
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from django.db import models
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output = []
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qn = self.quote_name
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for model in model_list:
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# Use `coalesce` to set the sequence for each model to the max pk
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# value if there are records, or 1 if there are none. Set the
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# `is_called` property (the third argument to `setval`) to true if
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# there are records (as the max pk value is already in use),
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# otherwise set it to false. Use pg_get_serial_sequence to get the
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# underlying sequence name from the table name and column name.
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for f in model._meta.local_fields:
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if isinstance(f, models.AutoField):
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output.append(
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"%s setval(pg_get_serial_sequence('%s','%s'), "
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"coalesce(max(%s), 1), max(%s) %s null) %s %s;"
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% (
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style.SQL_KEYWORD("SELECT"),
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style.SQL_TABLE(qn(model._meta.db_table)),
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style.SQL_FIELD(f.column),
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style.SQL_FIELD(qn(f.column)),
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style.SQL_FIELD(qn(f.column)),
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style.SQL_KEYWORD("IS NOT"),
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style.SQL_KEYWORD("FROM"),
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style.SQL_TABLE(qn(model._meta.db_table)),
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)
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)
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# Only one AutoField is allowed per model, so don't bother
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# continuing.
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break
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return output
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def prep_for_iexact_query(self, x):
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return x
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def max_name_length(self):
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"""
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Return the maximum length of an identifier.
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The maximum length of an identifier is 63 by default, but can be
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changed by recompiling PostgreSQL after editing the NAMEDATALEN
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macro in src/include/pg_config_manual.h.
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This implementation returns 63, but can be overridden by a custom
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database backend that inherits most of its behavior from this one.
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"""
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return 63
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def distinct_sql(self, fields, params):
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if fields:
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params = [param for param_list in params for param in param_list]
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return (["DISTINCT ON (%s)" % ", ".join(fields)], params)
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else:
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return ["DISTINCT"], []
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def last_executed_query(self, cursor, sql, params):
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# https://www.psycopg.org/docs/cursor.html#cursor.query
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# The query attribute is a Psycopg extension to the DB API 2.0.
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if cursor.query is not None:
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return cursor.query.decode()
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return None
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def return_insert_columns(self, fields):
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if not fields:
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return "", ()
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columns = [
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"%s.%s"
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% (
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self.quote_name(field.model._meta.db_table),
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self.quote_name(field.column),
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)
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for field in fields
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]
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return "RETURNING %s" % ", ".join(columns), ()
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def bulk_insert_sql(self, fields, placeholder_rows):
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placeholder_rows_sql = (", ".join(row) for row in placeholder_rows)
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values_sql = ", ".join("(%s)" % sql for sql in placeholder_rows_sql)
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return "VALUES " + values_sql
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def adapt_datefield_value(self, value):
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return value
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def adapt_datetimefield_value(self, value):
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return value
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def adapt_timefield_value(self, value):
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return value
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def adapt_decimalfield_value(self, value, max_digits=None, decimal_places=None):
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return value
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def adapt_ipaddressfield_value(self, value):
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if value:
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return Inet(value)
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return None
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def subtract_temporals(self, internal_type, lhs, rhs):
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if internal_type == "DateField":
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lhs_sql, lhs_params = lhs
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rhs_sql, rhs_params = rhs
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params = (*lhs_params, *rhs_params)
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return "(interval '1 day' * (%s - %s))" % (lhs_sql, rhs_sql), params
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return super().subtract_temporals(internal_type, lhs, rhs)
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def explain_query_prefix(self, format=None, **options):
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extra = {}
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# Normalize options.
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if options:
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options = {
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name.upper(): "true" if value else "false"
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for name, value in options.items()
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}
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for valid_option in self.explain_options:
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value = options.pop(valid_option, None)
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if value is not None:
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extra[valid_option] = value
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prefix = super().explain_query_prefix(format, **options)
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if format:
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extra["FORMAT"] = format
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if extra:
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prefix += " (%s)" % ", ".join("%s %s" % i for i in extra.items())
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return prefix
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def on_conflict_suffix_sql(self, fields, on_conflict, update_fields, unique_fields):
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if on_conflict == OnConflict.IGNORE:
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return "ON CONFLICT DO NOTHING"
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if on_conflict == OnConflict.UPDATE:
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return "ON CONFLICT(%s) DO UPDATE SET %s" % (
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", ".join(map(self.quote_name, unique_fields)),
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", ".join(
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[
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f"{field} = EXCLUDED.{field}"
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for field in map(self.quote_name, update_fields)
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]
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),
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)
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return super().on_conflict_suffix_sql(
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fields,
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on_conflict,
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update_fields,
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unique_fields,
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)
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