sqlite - 如何指示 SQLAlchemy 在 create_all() 上创建 SQLite FTS3 表？

Question

我希望 SQLAlchemy 在.create_all(). 我需要添加哪些特殊选项以便它知道CREATE VIRTUAL TABLE ... USING FTS3(tokenizer=...)？

Answer 1

据我所知，要实现此功能，您必须改进 sqlite 方言以更改 create_table 行为。

但是您可以通过“monkeypatching”使用这种快速但丑陋的解决方案

# ugly monkeypatch
from sqlalchemy.dialects.sqlite.base import SQLiteDDLCompiler

old_create_table = SQLiteDDLCompiler.visit_create_table

def new_create_table(*args, **kwargs):
    sql = old_create_table(*args, **kwargs)
    # TODO 
    # 1) check table with FTS3 
    # 2) change sql to CREATE VIRTUAL TABLE ... USING FTS3(tokenizer=...)
    print 'SQL: %s' % sql
    return sql

SQLiteDDLCompiler.visit_create_table = new_create_table
# end of ugly monkey patch

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import schema, MetaData, Column, Integer

metadata = MetaData()
Base = declarative_base(metadata=metadata) 

class MyModel(Base):
    __tablename__ = 'table'
    id = Column(Integer, primary_key=True)

if __name__ == '__main__':
    from sqlalchemy import create_engine
    engine = create_engine('sqlite:///', echo=True)
    metadata.bind = engine
    metadata.create_all()