Source code for langchain_community.query_constructors.tencentvectordb
from __future__ import annotations
from typing import Optional, Sequence, Tuple
from langchain_core.structured_query import (
Comparator,
Comparison,
Operation,
Operator,
StructuredQuery,
Visitor,
)
[docs]class TencentVectorDBTranslator(Visitor):
"""将StructuredQuery翻译为腾讯VectorDB查询。"""
COMPARATOR_MAP = {
Comparator.EQ: "=",
Comparator.NE: "!=",
Comparator.GT: ">",
Comparator.GTE: ">=",
Comparator.LT: "<",
Comparator.LTE: "<=",
Comparator.IN: "in",
Comparator.NIN: "not in",
}
allowed_comparators: Optional[Sequence[Comparator]] = list(COMPARATOR_MAP.keys())
allowed_operators: Optional[Sequence[Operator]] = [
Operator.AND,
Operator.OR,
Operator.NOT,
]
[docs] def __init__(self, meta_keys: Optional[Sequence[str]] = None):
"""初始化翻译器。
参数:
meta_keys:要在查询中使用的元键列表。默认值:[]。
"""
self.meta_keys = meta_keys or []
[docs] def visit_operation(self, operation: Operation) -> str:
"""访问一个操作节点并返回翻译后的查询。
参数:
operation: 要访问的操作节点。
返回:
翻译后的查询。
"""
if operation.operator in (Operator.AND, Operator.OR):
ret = f" {operation.operator.value} ".join(
[arg.accept(self) for arg in operation.arguments]
)
if operation.operator == Operator.OR:
ret = f"({ret})"
return ret
else:
return f"not ({operation.arguments[0].accept(self)})"
[docs] def visit_comparison(self, comparison: Comparison) -> str:
"""访问一个比较节点并返回翻译后的查询。
参数:
comparison: 要访问的比较节点。
返回:
翻译后的查询。
"""
if self.meta_keys and comparison.attribute not in self.meta_keys:
raise ValueError(
f"Expr Filtering found Unsupported attribute: {comparison.attribute}"
)
if comparison.comparator in self.COMPARATOR_MAP:
if comparison.comparator in [Comparator.IN, Comparator.NIN]:
value = map(
lambda x: f'"{x}"' if isinstance(x, str) else x, comparison.value
)
return (
f"{comparison.attribute}"
f" {self.COMPARATOR_MAP[comparison.comparator]} "
f"({', '.join(value)})"
)
if isinstance(comparison.value, str):
return (
f"{comparison.attribute} "
f"{self.COMPARATOR_MAP[comparison.comparator]}"
f' "{comparison.value}"'
)
return (
f"{comparison.attribute}"
f" {self.COMPARATOR_MAP[comparison.comparator]} "
f"{comparison.value}"
)
else:
raise ValueError(f"Unsupported comparator {comparison.comparator}")
[docs] def visit_structured_query(
self, structured_query: StructuredQuery
) -> Tuple[str, dict]:
"""访问一个结构化查询节点并返回翻译后的查询。
参数:
structured_query: 要访问的StructuredQuery节点。
返回:
翻译后的查询和查询参数。
"""
if structured_query.filter is None:
kwargs = {}
else:
kwargs = {"expr": structured_query.filter.accept(self)}
return structured_query.query, kwargs