Question

这是代码：

from sqlalchemy import Table, Column, Index, String, MetaData, func, create_engine

md = MetaData()
tbl = Table('t1', md, Column('col1', String()))
idx = Index(
    'idx1',
    func.lower(tbl.c.col1),
    postgresql_ops={'col1': 'text_pattern_ops'},
)

e = create_engine("postgresql://postgres:postgres@localhost/test", echo=True)
with e.connect() as c:
    md.create_all(c)

输出

 Column |       Type        | Modifiers 
--------+-------------------+-----------
 col1   | character varying | 

Indexes:
    "idx1" btree (lower(col1::text))  # NO text_pattern_ops!!!

Answer 1

根据docs，您需要在表达式上添加标签：

idx = Index(
    'idx1',
    func.lower(tbl.c.col1).label('lower_col1'),
    postgresql_ops={'lower_col1': 'text_pattern_ops'},
)

SqlAlchemy：当func.lower（列）时，将忽略索引postgresql_ops

1 个答案: