Current File : //opt/hc_python/lib64/python3.8/site-packages/sqlalchemy/dialects/mysql/expression.py
# dialects/mysql/expression.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: ignore-errors
from ... import exc
from ... import util
from ...sql import coercions
from ...sql import elements
from ...sql import operators
from ...sql import roles
from ...sql.base import _generative
from ...sql.base import Generative
from ...util.typing import Self
class match(Generative, elements.BinaryExpression):
"""Produce a ``MATCH (X, Y) AGAINST ('TEXT')`` clause.
E.g.::
from sqlalchemy import desc
from sqlalchemy.dialects.mysql import match
match_expr = match(
users_table.c.firstname,
users_table.c.lastname,
against="Firstname Lastname",
)
stmt = (
select(users_table)
.where(match_expr.in_boolean_mode())
.order_by(desc(match_expr))
)
Would produce SQL resembling::
SELECT id, firstname, lastname
FROM user
WHERE MATCH(firstname, lastname) AGAINST (:param_1 IN BOOLEAN MODE)
ORDER BY MATCH(firstname, lastname) AGAINST (:param_2) DESC
The :func:`_mysql.match` function is a standalone version of the
:meth:`_sql.ColumnElement.match` method available on all
SQL expressions, as when :meth:`_expression.ColumnElement.match` is
used, but allows to pass multiple columns
:param cols: column expressions to match against
:param against: expression to be compared towards
:param in_boolean_mode: boolean, set "boolean mode" to true
:param in_natural_language_mode: boolean , set "natural language" to true
:param with_query_expansion: boolean, set "query expansion" to true
.. versionadded:: 1.4.19
.. seealso::
:meth:`_expression.ColumnElement.match`
"""
__visit_name__ = "mysql_match"
inherit_cache = True
def __init__(self, *cols, **kw):
if not cols:
raise exc.ArgumentError("columns are required")
against = kw.pop("against", None)
if against is None:
raise exc.ArgumentError("against is required")
against = coercions.expect(
roles.ExpressionElementRole,
against,
)
left = elements.BooleanClauseList._construct_raw(
operators.comma_op,
clauses=cols,
)
left.group = False
flags = util.immutabledict(
{
"mysql_boolean_mode": kw.pop("in_boolean_mode", False),
"mysql_natural_language": kw.pop(
"in_natural_language_mode", False
),
"mysql_query_expansion": kw.pop("with_query_expansion", False),
}
)
if kw:
raise exc.ArgumentError("unknown arguments: %s" % (", ".join(kw)))
super().__init__(left, against, operators.match_op, modifiers=flags)
@_generative
def in_boolean_mode(self) -> Self:
"""Apply the "IN BOOLEAN MODE" modifier to the MATCH expression.
:return: a new :class:`_mysql.match` instance with modifications
applied.
"""
self.modifiers = self.modifiers.union({"mysql_boolean_mode": True})
return self
@_generative
def in_natural_language_mode(self) -> Self:
"""Apply the "IN NATURAL LANGUAGE MODE" modifier to the MATCH
expression.
:return: a new :class:`_mysql.match` instance with modifications
applied.
"""
self.modifiers = self.modifiers.union({"mysql_natural_language": True})
return self
@_generative
def with_query_expansion(self) -> Self:
"""Apply the "WITH QUERY EXPANSION" modifier to the MATCH expression.
:return: a new :class:`_mysql.match` instance with modifications
applied.
"""
self.modifiers = self.modifiers.union({"mysql_query_expansion": True})
return self
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