276 lines
11 KiB
Python
276 lines
11 KiB
Python
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# -*- coding: utf-8 -*-
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# Part of Odoo. See LICENSE file for full copyright and licensing details.
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from odoo.tools.sql import make_identifier, SQL, IDENT_RE
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def _sql_table(table: str | SQL | None) -> SQL | None:
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""" Wrap an optional table as an SQL object. """
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if isinstance(table, str):
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return SQL.identifier(table) if IDENT_RE.match(table) else SQL(f"({table})")
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return table
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def _sql_from_table(alias: str, table: SQL | None) -> SQL:
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""" Return a FROM clause element from ``alias`` and ``table``. """
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if table is None:
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return SQL.identifier(alias)
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return SQL("%s AS %s", table, SQL.identifier(alias))
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def _sql_from_join(kind: SQL, alias: str, table: SQL | None, condition: SQL) -> SQL:
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""" Return a FROM clause element for a JOIN. """
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return SQL("%s %s ON (%s)", kind, _sql_from_table(alias, table), condition)
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_SQL_JOINS = {
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"JOIN": SQL("JOIN"),
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"LEFT JOIN": SQL("LEFT JOIN"),
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}
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def _generate_table_alias(src_table_alias, link):
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""" Generate a standard table alias name. An alias is generated as following:
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- the base is the source table name (that can already be an alias)
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- then, the joined table is added in the alias using a 'link field name'
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that is used to render unique aliases for a given path
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- the name is shortcut if it goes beyond PostgreSQL's identifier limits
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.. code-block:: pycon
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>>> _generate_table_alias('res_users', link='parent_id')
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'res_users__parent_id'
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:param str src_table_alias: alias of the source table
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:param str link: field name
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:return str: alias
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"""
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return make_identifier(f"{src_table_alias}__{link}")
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class Query(object):
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""" Simple implementation of a query object, managing tables with aliases,
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join clauses (with aliases, condition and parameters), where clauses (with
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parameters), order, limit and offset.
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:param cr: database cursor (for lazy evaluation)
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:param alias: name or alias of the table
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:param table: a table expression (``str`` or ``SQL`` object), optional
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"""
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def __init__(self, cr, alias: str, table: (str | SQL | None) = None):
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# database cursor
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self._cr = cr
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# tables {alias: table(SQL|None)}
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self._tables = {alias: _sql_table(table)}
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# joins {alias: (kind(SQL), table(SQL|None), condition(SQL))}
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self._joins = {}
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# holds the list of WHERE conditions (to be joined with 'AND')
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self._where_clauses = []
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# order, limit, offset
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self._order = None
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self.limit = None
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self.offset = None
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# memoized result
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self._ids = None
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def make_alias(self, alias: str, link: str) -> str:
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""" Return an alias based on ``alias`` and ``link``. """
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return _generate_table_alias(alias, link)
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def add_table(self, alias: str, table: (str | SQL | None) = None):
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""" Add a table with a given alias to the from clause. """
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assert alias not in self._tables and alias not in self._joins, f"Alias {alias!r} already in {self}"
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self._tables[alias] = _sql_table(table)
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self._ids = None
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def add_join(self, kind: str, alias: str, table: str | SQL | None, condition: SQL):
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""" Add a join clause with the given alias, table and condition. """
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sql_kind = _SQL_JOINS.get(kind.upper())
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assert sql_kind is not None, f"Invalid JOIN type {kind!r}"
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assert alias not in self._tables, f"Alias {alias!r} already used"
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table = _sql_table(table)
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if alias in self._joins:
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assert self._joins[alias] == (sql_kind, table, condition)
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else:
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self._joins[alias] = (sql_kind, table, condition)
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self._ids = None
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def add_where(self, where_clause: str | SQL, where_params=()):
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""" Add a condition to the where clause. """
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self._where_clauses.append(SQL(where_clause, *where_params))
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self._ids = None
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def join(self, lhs_alias: str, lhs_column: str, rhs_table: str, rhs_column: str, link: str):
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"""
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Perform a join between a table already present in the current Query object and
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another table. This method is essentially a shortcut for methods :meth:`~.make_alias`
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and :meth:`~.add_join`.
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:param str lhs_alias: alias of a table already defined in the current Query object.
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:param str lhs_column: column of `lhs_alias` to be used for the join's ON condition.
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:param str rhs_table: name of the table to join to `lhs_alias`.
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:param str rhs_column: column of `rhs_alias` to be used for the join's ON condition.
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:param str link: used to generate the alias for the joined table, this string should
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represent the relationship (the link) between both tables.
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"""
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assert lhs_alias in self._tables or lhs_alias in self._joins, "Alias %r not in %s" % (lhs_alias, str(self))
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rhs_alias = self.make_alias(lhs_alias, link)
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condition = SQL("%s = %s", SQL.identifier(lhs_alias, lhs_column), SQL.identifier(rhs_alias, rhs_column))
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self.add_join('JOIN', rhs_alias, rhs_table, condition)
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return rhs_alias
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def left_join(self, lhs_alias: str, lhs_column: str, rhs_table: str, rhs_column: str, link: str):
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""" Add a LEFT JOIN to the current table (if necessary), and return the
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alias corresponding to ``rhs_table``.
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See the documentation of :meth:`join` for a better overview of the
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arguments and what they do.
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"""
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assert lhs_alias in self._tables or lhs_alias in self._joins, "Alias %r not in %s" % (lhs_alias, str(self))
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rhs_alias = self.make_alias(lhs_alias, link)
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condition = SQL("%s = %s", SQL.identifier(lhs_alias, lhs_column), SQL.identifier(rhs_alias, rhs_column))
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self.add_join('LEFT JOIN', rhs_alias, rhs_table, condition)
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return rhs_alias
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@property
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def order(self) -> SQL | None:
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return self._order
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@order.setter
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def order(self, value: SQL | str | None):
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self._order = SQL(value) if value is not None else None
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@property
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def table(self) -> str:
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""" Return the query's main table, i.e., the first one in the FROM clause. """
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return next(iter(self._tables))
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@property
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def from_clause(self) -> SQL:
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""" Return the FROM clause of ``self``, without the FROM keyword. """
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tables = SQL(", ").join(
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_sql_from_table(alias, table)
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for alias, table in self._tables.items()
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)
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if not self._joins:
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return tables
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items = [tables]
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for alias, (kind, table, condition) in self._joins.items():
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items.append(_sql_from_join(kind, alias, table, condition))
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return SQL(" ").join(items)
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@property
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def where_clause(self) -> SQL:
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""" Return the WHERE condition of ``self``, without the WHERE keyword. """
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return SQL(" AND ").join(self._where_clauses)
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def is_empty(self):
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""" Return whether the query is known to return nothing. """
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return self._ids == ()
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def select(self, *args: str | SQL) -> SQL:
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""" Return the SELECT query as an ``SQL`` object. """
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sql_args = map(SQL, args) if args else [SQL.identifier(self.table, 'id')]
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return SQL(
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"%s%s%s%s%s%s",
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SQL("SELECT %s", SQL(", ").join(sql_args)),
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SQL(" FROM %s", self.from_clause),
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SQL(" WHERE %s", self.where_clause) if self._where_clauses else SQL(),
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SQL(" ORDER BY %s", self._order) if self._order else SQL(),
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SQL(" LIMIT %s", self.limit) if self.limit else SQL(),
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SQL(" OFFSET %s", self.offset) if self.offset else SQL(),
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)
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def subselect(self, *args: str | SQL) -> SQL:
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""" Similar to :meth:`.select`, but for sub-queries.
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This one avoids the ORDER BY clause when possible,
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and includes parentheses around the subquery.
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"""
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if self._ids is not None and not args:
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# inject the known result instead of the subquery
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return SQL("%s", self._ids or (None,))
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if self.limit or self.offset:
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# in this case, the ORDER BY clause is necessary
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return SQL("(%s)", self.select(*args))
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sql_args = map(SQL, args) if args else [SQL.identifier(self.table, 'id')]
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return SQL(
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"(%s%s%s)",
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SQL("SELECT %s", SQL(", ").join(sql_args)),
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SQL(" FROM %s", self.from_clause),
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SQL(" WHERE %s", self.where_clause) if self._where_clauses else SQL(),
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)
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def get_sql(self):
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""" Returns (query_from, query_where, query_params). """
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from_string, from_params = self.from_clause
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where_string, where_params = self.where_clause
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return from_string, where_string, from_params + where_params
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def get_result_ids(self):
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""" Return the result of ``self.select()`` as a tuple of ids. The result
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is memoized for future use, which avoids making the same query twice.
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"""
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if self._ids is None:
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self._cr.execute(self.select())
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self._ids = tuple(row[0] for row in self._cr.fetchall())
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return self._ids
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def set_result_ids(self, ids, ordered=True):
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""" Set up the query to return the lines given by ``ids``. The parameter
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``ordered`` tells whether the query must be ordered to match exactly the
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sequence ``ids``.
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"""
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assert not (self._joins or self._where_clauses or self.limit or self.offset), \
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"Method set_result_ids() can only be called on a virgin Query"
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ids = tuple(ids)
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if not ids:
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self.add_where("FALSE")
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elif ordered:
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# This guarantees that self.select() returns the results in the
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# expected order of ids:
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# SELECT "stuff".id
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# FROM "stuff"
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# JOIN (SELECT * FROM unnest(%s) WITH ORDINALITY) AS "stuff__ids"
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# ON ("stuff"."id" = "stuff__ids"."unnest")
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# ORDER BY "stuff__ids"."ordinality"
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alias = self.join(
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self.table, 'id',
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SQL('(SELECT * FROM unnest(%s) WITH ORDINALITY)', list(ids)), 'unnest',
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'ids',
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)
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self.order = SQL.identifier(alias, 'ordinality')
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else:
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self.add_where(SQL("%s IN %s", SQL.identifier(self.table, 'id'), ids))
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self._ids = ids
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def __str__(self):
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sql = self.select()
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return f"<Query: {sql.code!r} with params: {sql.params!r}>"
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def __bool__(self):
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return bool(self.get_result_ids())
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def __len__(self):
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if self._ids is None:
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if self.limit or self.offset:
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# optimization: generate a SELECT FROM, and then count the rows
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sql = SQL("SELECT COUNT(*) FROM (%s) t", self.select(""))
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else:
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sql = self.select('COUNT(*)')
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self._cr.execute(sql)
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return self._cr.fetchone()[0]
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return len(self.get_result_ids())
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def __iter__(self):
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return iter(self.get_result_ids())
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