I am doing a simple search input field. In Ecto part, I am checking if the user input is decimal or string with below case do method.
Because the CashflowEntry.amount is a :decimal type. I gotta seperate the query, one for decimal and one for string.
this seem like fine, but I believe there are better ways to achieve this? Example, 1 query only, but with a conditional where ce.amount == ^amount_decimal? i don’t know, i cannot think of better way.
def search(search_term) do
case Decimal.parse(search_term) do
{amount_decimal, _} ->
# Input is decimal
wildcard_search = "%#{search_term}%"
from(ce in CashflowEntry,
where: ce.amount == ^amount_decimal or ilike(ce.note, ^wildcard_search)
)
|> Repo.all()
_ ->
# Input is alphanumeric
wildcard_search = "%#{search_term}%"
from(ce in CashflowEntry,
where: ilike(ce.note, ^wildcard_search)
)
|> Repo.all()
end
end
Newbie, coming from python, in love with elixir phoenix ecto
I am sorry if this question has been asked before. I am not sure what the term to search for such solution.
The simplest thing you can do in this particular situation, is refactor the code a little to move out the expressions which you are doing in either branch of the code:
def search(search_term) do
wildcard_search = "%#{search_term}%"
query = case Decimal.parse(search_term) do
{amount_decimal, _} ->
# Input is decimal
from(ce in CashflowEntry,
where: ce.amount == ^amount_decimal or ilike(ce.note, ^wildcard_search)
)
_ ->
# Input is alphanumeric
from(ce in CashflowEntry, where: ilike(ce.note, ^wildcard_search))
end
Repo.all(query)
end
And at this point, you might as well move the case statement to a helper function:
def search(search_term) do
search_term
|> search_query()
|> Repo.all()
end
# You might consider making this function public to test it separately
defp search_query(search_term) do
wildcard_search = "%#{search_term}%"
query = case Decimal.parse(search_term) do
{amount_decimal, _} ->
# Input is decimal
from(ce in CashflowEntry,
where: ce.amount == ^amount_decimal or ilike(ce.note, ^wildcard_search)
)
_ ->
# Input is alphanumeric
from(ce in CashflowEntry, where: ilike(ce.note, ^wildcard_search))
end
end
There is to my knowledge no simple possibility to move the check of whether the input is a string or a number into the query to turn this code into a single query. (At least not without writing a raw SQL fragment, which is usually not recommended).
Possibly like this. Indeed, as per @fuelen, use of dynamic/2 is the key.
import Ecto.Query
def search(term) when is_binary(term)
CashFlowEntry |> search_where(term) |> Repo.all()
end
defp search_where(query, term) when is_binary(term) do
case Decimal.parse(term) do
{amount, _} -> where(query, [x], x.amount == ^amount or ilike(x.note, ^term))
_ -> where(query, [x], ilike(x.note, ^term))
end
end
The dynamic/2 is the good one. But I decide to temporarily go with this first, because I am new to Phoenix Ecto and this is more straight forward for me.
will move to dynamic/2 once i am more comfortable with phoenix ecto.