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Next let's look at "update" operations in the console.
After retrieving a model object from the database, we can modify its data and update the database record. This is much the same as working with a new model object; we just assign new values to the existing object's attributes, and call "save" on it.
Let's suppose we wanted to update a posts's title:
- As before, we can get a collection of all the Post objects by calling
Post.all. - We can look at the "id" attribute of the one we want to update, and then retrieve it by passing the ID to the "find" method. We'll assign the object we get back to a variable:
post = Post.find(7) - As before, we can set the attributes the same way we would on any other Ruby object. So let's change the title:
post.title = "I've been updated!" - Once again, these changes only exist in your computer's memory, not in the database. We need to call the "save" method on the object to save it to the database:
post.save
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Next, let's look at update operations in the console.
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After retrieving a model object from the database, we can modify the object and
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update the database record.
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This is much the same as working with a new model object.
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We just assign new values, the existing object's attributes and call save on it.
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Let's suppose we wanted to update a post title.
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As before, we can get a collection of all the posts objects by calling Post.all.
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We can look at the ID attribute of the one we want to modify and
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then retrieve it by passing the ID to the find method.
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We'll assign the object we get back to a variable, post = Post.find(3).
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As before we can set the attributes the same way we would on any other
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Ruby object.
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So let's change the title.
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Post.title =" I've been
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updated!" Once again,
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these changes only exist in your computer's memory, not in the database.
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We need to call the save method on the object to update its database record.
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Post.save.
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We'll see an SQL query that updates the record in the database..
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And the next time we query that database,
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we'll see the updated title instead of the old one.
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