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:
size
, precision
, and scale
constraints
on types because columns in SQLite have no types, and SQLite will not coerce
any stored value. Thus, all "strings" are TEXT
and "numerics" will have
arbitrary precision regardless of the declared column constraints. The lone
exception to this rule are Decimal types which accept precision
and
scale
options because these constraints are handled in the driver
software, not the SQLite database.DATETIME
column with a NOT NULL
constraint, SQLite will require a default value to be provided. The only
default value which would make sense in this situation is
CURRENT_TIMESTAMP
; however, when adding a column to a table, defaults must
be constant values. Therefore, in this situation the NOT NULL
constraint
will be ignored so that a default value does not need to be provided.concurrently
and using
values are silently
ignored since they do not apply to SQLite.