- from flask_sqlalchemy import SQLAlchemy
 - from sqlalchemy import MetaData
 - 
 - from dify_app import DifyApp
 - 
 - POSTGRES_INDEXES_NAMING_CONVENTION = {
 -     "ix": "%(column_0_label)s_idx",
 -     "uq": "%(table_name)s_%(column_0_name)s_key",
 -     "ck": "%(table_name)s_%(constraint_name)s_check",
 -     "fk": "%(table_name)s_%(column_0_name)s_fkey",
 -     "pk": "%(table_name)s_pkey",
 - }
 - 
 - metadata = MetaData(naming_convention=POSTGRES_INDEXES_NAMING_CONVENTION)
 - db = SQLAlchemy(metadata=metadata)
 - 
 - 
 - def init_app(app: DifyApp):
 -     db.init_app(app)
 
 
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