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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"How to create computed columns ?","articleBody":"### First Check\n\n- [X] I added a very descriptive title to this issue.\n- [X] I used the GitHub search to find a similar issue and didn't find it.\n- [X] I searched the SQLModel documentation, with the integrated search.\n- [X] I already searched in Google \"How to X in SQLModel\" and didn't find any information.\n- [X] I already read and followed all the tutorial in the docs and didn't find an answer.\n- [X] I already checked if it is not related to SQLModel but to [Pydantic](https://github.com/samuelcolvin/pydantic).\n- [X] I already checked if it is not related to SQLModel but to [SQLAlchemy](https://github.com/sqlalchemy/sqlalchemy).\n\n### Commit to Help\n\n- [X] I commit to help with one of those options 👆\n\n### Example Code\n\n```python\nclass Album(SQLModel):\r\n    title: str\r\n    slug: str\r\n    description: str\r\n\r\n\r\n# what i've tried but doesn't work e.g : \r\n\r\n#     slug: str = column_property(slugify(title))\r\n# E   NameError: name 'title' is not defined\r\n\r\nclass Album(SQLModel):\r\n    title: str\r\n    slug: str = column_property(slugify(title))\r\n    description: str\n```\n\n\n### Description\n\nI'm trying to generate a column named \"slug\" that is a slugified version of \"title\" so it should be persisted in database, and be updated when title changes. \r\n\r\nBut so far no luck, I've looked at column property but didn't manage to make it work with SQLModel.  I saw that there are events \"before update\" ... but I don't think this is the way to go\n\n### Operating System\n\nWindows\n\n### Operating System Details\n\n_No response_\n\n### SQLModel Version\n\n0.0.4\n\n### Python Version\n\n3.9.2\n\n### Additional Context\n\n_No response_","author":{"url":"https://github.com/sorasful","@type":"Person","name":"sorasful"},"datePublished":"2021-10-30T11:35:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":14},"url":"https://github.com/150/sqlmodel/issues/150"}