sqlalchemy - automatically truncate strings

gistfile1.txt

#Create a TypeDecorator in your base model for an even more generic answer. Then, use this TypeDecorator instead of string.

#In base.py

 from sqlalchemy.types import TypeDecorator

  class TruncateString(TypeDecorator):
    """trim spaces from the string"""

    impl = db.String
    cache_ok = True

    def process_bind_param(self, value, dialect):
        # In case you have nullable string fields and pass None
        if value and len(value) > self.impl.length:
            value = value[:self.impl.length]
        return value if value else value

    def copy(self, **kw):
        return TruncateString(self.impl.length)
#Now, in your yourModel.py, use this type.

    from flask_app.models.base import *

class CampaignScript(BaseModel):
    __tablename__ = 'campaign_script'

    name = Column(TruncateString(200))
    subject = Column(TruncateString(200))
    comments = Column(TruncateString(200))
    language = Column(TruncateString(200))
    script = Column(NVARCHAR(None))
    user_id = Column(TruncateString)
    account_id = Column(Integer)
    comm_type = Column(TruncateString(45))
    short_name = Column(TruncateString(75))
    released_locked = Column(Boolean())