Sqlite.Ecto
is a SQLite3 Adapter for Ecto.
Read the tutorial for a detailed example of how to setup and use a SQLite repo with Ecto, or just check-out the CliffsNotes in the sections below if you want to get started quickly.
Sqlite.Ecto
relies on Sqlitex and
esqlite. Since esqlite uses
Erlang NIFs, you will need a valid C compiler to build the library.
Here is an example usage:
# In your config/config.exs file
config :my_app, Repo,
adapter: Sqlite.Ecto,
database: "ecto_simple.sqlite3"
# In your application code
defmodule Repo do
use Ecto.Repo,
otp_app: :my_app,
adapter: Sqlite.Ecto
end
defmodule Weather do
use Ecto.Model
schema "weather" do
field :city # Defaults to type :string
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
end
defmodule Simple do
import Ecto.Query
def sample_query do
query = from w in Weather,
where: w.prcp > 0 or is_nil(w.prcp),
select: w
Repo.all(query)
end
end
Add Sqlite.Ecto
as a dependency in your mix.exs
file.
def deps do
[{:sqlite_ecto, "~> 1.0.0"}]
end
You should also update your applications list to include both projects:
def application do
[applications: [:logger, :sqlite_ecto, :ecto]]
end
To use the adapter in your repo:
defmodule MyApp.Repo do
use Ecto.Repo,
otp_app: :my_app,
adapter: Sqlite.Ecto
end
The changeset functions
foreign_key_constraint/3
and
unique_constraint/3
are not supported by Sqlite.Ecto
because the underlying SQLite database does
not provide enough information when such constraints are violated to support
the features.
Note that SQLite does support both unique and foreign key constraints via
unique_index/3
and references/2
,
respectively. When such constraints are violated, they will raise
Sqlite.Ecto.Error
exceptions.
There are a few Ecto options which Sqlite.Ecto
silently ignores because
SQLite does not support them and raising an error on them does not make sense:
- Most column options will ignore
size
,precision
, andscale
constraints on types because columns in SQLite have no types, and SQLite will not coerce any stored value. Thus, all "strings" areTEXT
and "numerics" will have arbitrary precision regardless of the declared column constraints. The lone exception to this rule are Decimal types which acceptprecision
andscale
options because these constraints are handled in the driver software, not the SQLite database. - If we are altering a table to add a
DATETIME
column with aNOT NULL
constraint, SQLite will require a default value to be provided. The only default value which would make sense in this situation isCURRENT_TIMESTAMP
; however, when adding a column to a table, defaults must be constant values. Therefore, in this situation theNOT NULL
constraint will be ignored so that a default value does not need to be provided. - When creating an index,
concurrently
andusing
values are silently ignored since they do not apply to SQLite.