In Model Classes, I have seen this constant, CACHE_ID and CACHE_TAG, I know it is used to store data in the cache.

But how does it actually work. What should be considered while caching and flushing our custom variables?.

1 Answer 1


Cache id is used to identify a specific cache record.
If you save something in the cache you can later retrieve it by its id.
Cache tags are a way to assign labels to different cache records so you can later clear multiple cache entries based on those labels (tags).

For example, let's say you want to cache a category view page.
This will have as tags category_{id of category here}.
But the category page contains products. SO maybe you want to also add the tags product_{id of each product here}.

Now, when you change a product and/or a category you need to clean the cache for each entity involved.
So when you update a product you clear all cache entries with the tag product_{id of product here}.
This way, the category page cache I mentioned above will get cleared also.

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