如何在SqlAlchemy中表示长文本？

Question

我在将大文本保存到 MySQL 数据库时遇到问题。

该模型如下所示（请参阅列收据）：

class Receipt(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    product_id = db.Column(db.String(200))
    type = db.Column(Enum(ReceiptType), nullable=False)
    receipt = db.Column(db.Text(), nullable=False)
    source = db.Column(Enum(ReceiptSource), nullable=False)
    expiry_date = db.Column(db.TIMESTAMP(), nullable=False)
    account_id = db.Column(db.Integer, db.ForeignKey(Account.id), unique=True)
    account = db.relationship('Account', back_populates="receipt")

SQLALchemy中似乎没有LongText()，所以我像这样进行了迁移：

def upgrade():
    connection = op.get_bind()
    connection.execute("""
                ALTER TABLE main_db.receipt MODIFY COLUMN receipt LONGTEXT NOT NULL;
                """)

这是抛出的错误：

sqlalchemy.exc.DataError: (MySQLdb._exceptions.DataError) (1406, "Data too long for column 'receipt' at row 1")
[SQL: INSERT INTO main_db.receipt (product_id, type, receipt, source, expiry_date, account_id) VALUES (%s, %s, %s, %s, %s, %s)]
[parameters: ('com.myCompany.myApp.ios.standard.weekly', 'STANDARD', 'MILEegYJKoZIhvcNAQcCoILEazCCxGcCAQExCzAJBgUrDgMCGgUAMIK0GwYJKoZIhvcNAQcBoIK0DASCtAgxgrQEMAoCAQgCAQEEAhYAMAoCARQCAQEEAgwAMAsCAQECAQEEAwIBADALAgEDAgEBB ... (66774 characters truncated) ... FAMZIuVFjBSqfQ0dZ0FJGtSU1dwEHJW2B8Z4uj0IzJIAlQmFcZ57lIpAlTo3zDUlTOtbZmuyhpgFlB6MQXbgm+Ewm2nCnwWwoF8v7/ZNtcma96i1X3vuujgYDYoZ/EeMWPc3Rkoea6D7POigeTg==', 'IOS', datetime.datetime(2020, 5, 8, 16, 37, 6), 14)]
(Background on this error at: http://sqlalche.me/e/9h9h)

请问我缺少什么？

Answer 1

SQLAlchemy for MySQL 中长文本类型的表示方法是：

from sqlalchemy.dialects.mysql import LONGTEXT

class Receipt(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    long_text = db.Column(LONGTEXT)

对于其他类型，请参阅 SQLAlchemy 文档：https://docs.sqlalchemy.org/en/14/dialects/mysql.html#mysql-data-types

（SQLAlchemy v2.0版本： https://docs.sqlalchemy.org/en/20/dialects/mysql.html#mysql-data-types）

这也适用于flask-sqlalchemy。