toucan2.tools.transformed
deftransformscljmacro
(deftransforms model column->direction->fn)Define type transforms to use for a specific model. transforms should be a map of
{:column-name {:in <fn>, :out <fn>}}
:in transforms are applied to values going over the wire to the database; these generally only applied to values
passed at or near the top level to various functions; don't expect Toucan 2 to parse your SQL to find out which
parameter corresponds to what in order to apply transforms or to apply transforms inside JOINS in hand-written
HoneySQL. That said, unless you're doing something weird your transforms should generally get applied.
:out transforms are applied to values coming out of the database; since nothing weird really happens there this is
done consistently.
Transform functions for either case are skipped for nil values.
Example:
(deftransforms :models/user
{:type {:in name, :out keyword}})
You can also define transforms independently, and derive a model from them:
(deftransforms ::type-keyword
{:type {:in name, :out keyword}})
(derive :models/user ::type-keyword)
(derive :models/user ::some-other-transform)
Don't derive a model from multiple deftransforms for the same key in the same direction.
When multiple transforms match a given model they are combined into a single map of transforms with merge-with merge. If multiple transforms match a given column in a given direction, only one of them will be used; you should
assume which one is used is indeterminate. (This may be made an error, or at least a warning, in the future.)
Until upstream issue https://github.com/camsaul/methodical/issues/97 is resolved, you will have to specify which method should be applied first in cases of ambiguity using [[methodical.core/prefer-method!]]:
(m/prefer-method! transforms ::user-with-location ::user-with-password)
If you want to override transforms completely for a model, and ignore transforms from ancestors of a model, you can
create an :around method:
(m/defmethod toucan2.tools.transforms :around ::my-model
[_model]
{:field {:in name, :out keyword}})
Define type transforms to use for a specific model. `transforms` should be a map of
```clj
{:column-name {:in <fn>, :out <fn>}}
```
`:in` transforms are applied to values going over the wire to the database; these generally only applied to values
passed at or near the top level to various functions; don't expect Toucan 2 to parse your SQL to find out which
parameter corresponds to what in order to apply transforms or to apply transforms inside JOINS in hand-written
HoneySQL. That said, unless you're doing something weird your transforms should generally get applied.
`:out` transforms are applied to values coming out of the database; since nothing weird really happens there this is
done consistently.
Transform functions for either case are skipped for `nil` values.
Example:
```clj
(deftransforms :models/user
{:type {:in name, :out keyword}})
```
You can also define transforms independently, and derive a model from them:
```clj
(deftransforms ::type-keyword
{:type {:in name, :out keyword}})
(derive :models/user ::type-keyword)
(derive :models/user ::some-other-transform)
```
Don't derive a model from multiple [[deftransforms]] for the same key in the same direction.
When multiple transforms match a given model they are combined into a single map of transforms with `merge-with
merge`. If multiple transforms match a given column in a given direction, only one of them will be used; you should
assume which one is used is indeterminate. (This may be made an error, or at least a warning, in the future.)
Until upstream issue https://github.com/camsaul/methodical/issues/97 is resolved, you will have to specify which
method should be applied first in cases of ambiguity using [[methodical.core/prefer-method!]]:
```clj
(m/prefer-method! transforms ::user-with-location ::user-with-password)
```
If you want to override transforms completely for a model, and ignore transforms from ancestors of a model, you can
create an `:around` method:
```clj
(m/defmethod toucan2.tools.transforms :around ::my-model
[_model]
{:field {:in name, :out keyword}})
```transformsclj
(transforms model₁)Return a map of
{column-name {:in <fn>, :out <fn>}}
For a given model, all matching transforms are combined with merge-with merge in an indeterminate order, so don't
try to specify multiple transforms for the same column in the same direction for a given model -- compose your
transform functions instead if you want to do that. See toucan2.tools.transformed/deftransforms for more info.
Return a map of
```clj
{column-name {:in <fn>, :out <fn>}}
```
For a given `model`, all matching transforms are combined with `merge-with merge` in an indeterminate order, so don't
try to specify multiple transforms for the same column in the same direction for a given model -- compose your
transform functions instead if you want to do that. See [[toucan2.tools.transformed/deftransforms]] for more info.cljdoc is a website building & hosting documentation for Clojure/Script libraries
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