Ecto v2.0.0-beta.2 Ecto.Repo behaviour
Defines a repository.
A repository maps to an underlying data store, controlled by the adapter. For example, Ecto ships with a Postgres adapter that stores data into a PostgreSQL database.
When used, the repository expects the :otp_app
as option.
The :otp_app
should point to an OTP application that has
the repository configuration. For example, the repository:
defmodule Repo do
use Ecto.Repo, otp_app: :my_app
end
Could be configured with:
config :my_app, Repo,
adapter: Ecto.Adapters.Postgres,
database: "ecto_simple",
username: "postgres",
password: "postgres",
hostname: "localhost"
Most of the configuration that goes into the config
is specific
to the adapter, so check Ecto.Adapters.Postgres
documentation
for more information. However, some configuration is shared across
all adapters, they are:
:priv
- the directory where to keep repository data, like migrations, schema and more. Defaults to “priv/YOUR_REPO”:url
- an URL that specifies storage information. Read below for more information:loggers
- a list of{mod, fun, args}
tuples that are invoked by adapters for logging queries and other events. The given module and function will be called with a log entry (seeEcto.LogEntry
) and the given arguments. The invoked function must return theEcto.LogEntry
as result. The default value is:[{Ecto.LogEntry, :log, []}]
, which will callEcto.LogEntry.log/1
that will use Elixir’sLogger
in:debug
mode. You may pass any desired mod-fun-args triplet or[{Ecto.LogEntry, :log, [:info]}]
if you want to keep the current behaviour but use another log level.
URLs
Repositories by default support URLs. For example, the configuration above could be rewritten to:
config :my_app, Repo,
url: "ecto://postgres:postgres@localhost/ecto_simple"
The schema can be of any value. The path represents the database name while options are simply merged in.
URLs also support {:system, "KEY"}
to be given, telling Ecto to load
the configuration from the system environment instead:
config :my_app, Repo,
url: {:system, "DATABASE_URL"}
Shared options
Almost all of the repository operations below accept the following options:
:timeout
- The time in milliseconds to wait for the query call to finish,:infinity
will wait indefinitely (default: 15000);:pool_timeout
- The time in milliseconds to wait for calls to the pool to finish,:infinity
will wait indefinitely (default: 5000);:log
- When false, does not log the query
Such cases will be explicitly documented as well as any extra option.
Summary
Callbacks
Returns the adapter tied to the repository
A callback invoked by adapters that logs the given action
Calculate the given aggregate
over the given field
Fetches all entries from the data store matching the given query
Returns the adapter configuration stored in the :otp_app
environment
Deletes a struct using its primary key
Same as delete/2
but returns the struct or raises if the changeset is invalid
Deletes all entries matching the given query
Fetches a single struct from the data store where the primary key matches the given id
Similar to get/3
but raises Ecto.NoResultsError
if no record was found
Fetches a single result from the query
Similar to get_by/3
but raises Ecto.NoResultsError
if no record was found
Returns true if the current process is inside a transaction
Inserts a struct or a changeset
Same as insert/2
but returns the struct or raises if the changeset is invalid
Inserts all entries into the repository
Inserts or updates a changeset depending on whether the struct is persisted or not
Same as insert_or_update/2
but returns the struct or raises if the changeset
is invalid
Fetches a single result from the query
Similar to one/2
but raises Ecto.NoResultsError
if no record was found
Preloads all associations on the given struct or structs
Rolls back the current transaction
Starts any connection pooling or supervision and return {:ok, pid}
or just :ok
if nothing needs to be done
Shuts down the repository represented by the given pid
Runs the given function or Ecto.Multi
inside a transaction
Updates a changeset using its primary key
Same as update/2
but returns the struct or raises if the changeset is invalid
Updates all entries matching the given query with the given values
Types
t :: module
Callbacks
Specs
__log__(Ecto.LogEntry.t) :: Ecto.LogEntry.t
A callback invoked by adapters that logs the given action.
See Ecto.LogEntry
for more information and Ecto.Repo
module
documentation on setting up your own loggers.
Specs
aggregate(Ecto.Queryable.t, aggregate :: :avg | :count | :max | :min | :sum, field :: atom, Keyword.t) ::
term |
nil
Calculate the given aggregate
over the given field
.
If the query has a limit, offset or distinct set, it will be automatically wrapped in a subquery in order to return the proper result.
Any preload or select in the query will be ignored in favor of the column being aggregated.
The aggregation will fail if any group_by
field is set.
Options
See the “Shared options” section at the module documentation.
Examples
# Returns the number of visits per blog post
Repo.aggregate(Post, :avg, :visits)
# Returns the average number of visits for the top 10
query = from Post, limit: 10
Repo.aggregate(Post, :avg, :visits)
Specs
all(queryable :: Ecto.Query.t, opts :: Keyword.t) ::
[Ecto.Schema.t] |
no_return
Fetches all entries from the data store matching the given query.
May raise Ecto.QueryError
if query validation fails.
Options
See the “Shared options” section at the module documentation.
Example
# Fetch all post titles
query = from p in Post,
select: p.title
MyRepo.all(query)
Specs
config :: Keyword.t
Returns the adapter configuration stored in the :otp_app
environment.
Specs
delete(Ecto.Schema.t, Keyword.t) ::
{:ok, Ecto.Schema.t} |
{:error, Ecto.Changeset.t}
Deletes a struct using its primary key.
If the struct has no primary key, Ecto.NoPrimaryKeyFieldError
will be raised.
It returns {:ok, struct}
if the struct has been successfully
deleted or {:error, changeset}
if there was a validation
or a known constraint error.
Options
See the “Shared options” section at the module documentation.
Example
[post] = MyRepo.all(from(p in Post, where: p.id == 42))
case MyRepo.delete post do
{:ok, struct} -> # Deleted with success
{:error, changeset} -> # Something went wrong
end
Specs
delete!(Ecto.Schema.t, Keyword.t) ::
Ecto.Schema.t |
no_return
Same as delete/2
but returns the struct or raises if the changeset is invalid.
Specs
delete_all(queryable :: Ecto.Queryable.t, options :: Keyword.t) ::
{integer, nil | [term]} |
no_return
Deletes all entries matching the given query.
It returns a tuple containing the number of entries and any returned result as second element. If the database does not support RETURNING in DELETE statements or no return result was selected, the second element will be nil.
Options
:returning
- selects which fields to return. Whentrue
, returns all fields in the given struct. May be a list of fields, where a struct is still returned but only with the given fields. Orfalse
, where nothing is returned (the default). This option is not supported by all databases.
See the “Shared options” section at the module documentation for remaining options.
Examples
MyRepo.delete_all(Post)
from(p in Post, where: p.id < 10) |> MyRepo.delete_all
Specs
get(Ecto.Queryable.t, term, Keyword.t) ::
Ecto.Schema.t |
nil |
no_return
Fetches a single struct from the data store where the primary key matches the given id.
Returns nil
if no result was found. If the struct in the queryable
has no or more than one primary key, it will raise an argument error.
Options
See the “Shared options” section at the module documentation.
Specs
get!(Ecto.Queryable.t, term, Keyword.t) ::
Ecto.Schema.t |
nil |
no_return
Similar to get/3
but raises Ecto.NoResultsError
if no record was found.
Options
See the “Shared options” section at the module documentation.
Specs
get_by(Ecto.Queryable.t, Keyword.t | Map.t, Keyword.t) ::
Ecto.Schema.t |
nil |
no_return
Fetches a single result from the query.
Returns nil
if no result was found.
Options
See the “Shared options” section at the module documentation.
Example
MyRepo.get_by(Post, title: "My post")
Specs
get_by!(Ecto.Queryable.t, Keyword.t | Map.t, Keyword.t) ::
Ecto.Schema.t |
nil |
no_return
Similar to get_by/3
but raises Ecto.NoResultsError
if no record was found.
Options
See the “Shared options” section at the module documentation.
Example
MyRepo.get_by!(Post, title: "My post")
Specs
in_transaction? :: boolean
Returns true if the current process is inside a transaction.
Examples
MyRepo.in_transaction?
#=> false
MyRepo.transaction(fn ->
MyRepo.in_transaction? #=> true
end)
Specs
insert(Ecto.Schema.t | Ecto.Changeset.t, Keyword.t) ::
{:ok, Ecto.Schema.t} |
{:error, Ecto.Changeset.t}
Inserts a struct or a changeset.
In case a struct is given, the struct is converted into a changeset with all non-nil fields as part of the changeset.
In case a changeset is given, the changes in the changeset are merged with the struct fields, and all of them are sent to the database.
It returns {:ok, struct}
if the struct has been successfully
inserted or {:error, changeset}
if there was a validation
or a known constraint error.
Options
See the “Shared options” section at the module documentation.
Example
case MyRepo.insert %Post{title: "Ecto is great"} do
{:ok, struct} -> # Inserted with success
{:error, changeset} -> # Something went wrong
end
Specs
insert!(Ecto.Schema.t, Keyword.t) ::
Ecto.Schema.t |
no_return
Same as insert/2
but returns the struct or raises if the changeset is invalid.
Specs
insert_all(binary | {binary | nil, binary} | Ecto.Schema.t, [map | Keyword.t], opts :: Keyword.t) ::
{integer, nil | [term]} |
no_return
Inserts all entries into the repository.
It expects a schema (MyApp.User
) or a source ("users"
or
{"prefix", "users"}
) as first argument. The second argument
is a list of entries to be inserted, either as keyword lists
or as maps.
When a schema is given, the values given will be properly dumped
before being sent to the database. If the schema contains an
autogenerated ID field, it will be handled either at the adapter
or the storage layer. However any other autogenerated value, like
timestamps, won’t be autogenerated when using c:insert_all/3
.
This is by design as this function aims to be a more direct way
to insert data into the database without the conveniences of
c:insert/2
. This is also consistent with c:update_all/3
that
does not handle timestamps as well.
If a source is given, without a schema, the given fields are passed as is to the adapter.
Options
See the “Shared options” section at the module documentation.
Specs
insert_or_update(Ecto.Changeset.t, Keyword.t) ::
{:ok, Ecto.Schema.t} |
{:error, Ecto.Changeset.t}
Inserts or updates a changeset depending on whether the struct is persisted or not.
The distinction whether to insert or update will be made on the
Ecto.Schema.Metadata
field :state
. The :state
is automatically set by
Ecto when loading or building a schema.
Please note that for this to work, you will have to load existing structs from the database. So even if the struct exists, this won’t work:
struct = %Post{id: 'existing_id', ...}
MyRepo.insert_or_update changeset
# => {:error, "id already exists"}
Options
See the “Shared options” section at the module documentation.
Example
result =
case MyRepo.get(Post, id) do
nil -> %Post{id: id} # Post not found, we build one
post -> post # Post exists, let's use it
end
|> Post.changeset(changes)
|> MyRepo.insert_or_update
case result do
{:ok, struct} -> # Inserted or updated with success
{:error, changeset} -> # Something went wrong
end
Specs
insert_or_update!(Ecto.Changeset.t, Keyword.t) ::
Ecto.Schema.t |
no_return
Same as insert_or_update/2
but returns the struct or raises if the changeset
is invalid.
Specs
one(Ecto.Queryable.t, Keyword.t) ::
Ecto.Schema.t |
nil |
no_return
Fetches a single result from the query.
Returns nil
if no result was found. Raises if more than one entry.
Options
See the “Shared options” section at the module documentation.
Specs
one!(Ecto.Queryable.t, Keyword.t) ::
Ecto.Schema.t |
no_return
Similar to one/2
but raises Ecto.NoResultsError
if no record was found.
Raises if more than one entry.
Options
See the “Shared options” section at the module documentation.
Specs
preload(struct_or_structs, preloads :: term, opts :: Keyword.t) :: struct_or_structs when struct_or_structs: [Ecto.Schema.t] | Ecto.Schema.t
Preloads all associations on the given struct or structs.
This is similar to Ecto.Query.preload/3
except it allows
you to preload structs after they have been fetched from the
database.
In case the association was already loaded, preload won’t attempt to reload it.
Options
Besides the “Shared options” section at the module documentation, it accepts:
:force
- By default, Ecto won’t preload associations that are already loaded. By setting this option to true, any existing association will be discarded and reloaded.:in_parallel
- If the preloads must be done in parallel. It can only be performed when we have more than one preload and the repository is not in a transaction. Defaults totrue
.:prefix
- the prefix to fetch preloads from. By default, queries will use the same prefix as the one in the given collection. This option allows the prefix to be changed.
Examples
posts = Repo.preload posts, :comments
posts = Repo.preload posts, comments: :permalinks
posts = Repo.preload posts, comments: from(c in Comment, order_by: c.published_at)
Specs
rollback(any) :: no_return
Rolls back the current transaction.
The transaction will return the value given as {:error, value}
.
Specs
start_link ::
{:ok, pid} |
{:error, {:already_started, pid}} |
{:error, term}
Starts any connection pooling or supervision and return {:ok, pid}
or just :ok
if nothing needs to be done.
Returns {:error, {:already_started, pid}}
if the repo is already
started or {:error, term}
in case anything else goes wrong.
Specs
stop(pid, timeout) :: :ok
Shuts down the repository represented by the given pid.
Specs
transaction((... -> any) | Ecto.Multi.t, Keyword.t) ::
{:ok, any} |
{:error, any} |
{:error, atom, any, %{atom => any}}
Runs the given function or Ecto.Multi
inside a transaction.
Use with function
If an unhandled error occurs the transaction will be rolled back
and the error will bubble up from the transaction function.
If no error occurred the transaction will be committed when the
function returns. A transaction can be explicitly rolled back
by calling rollback/1
, this will immediately leave the function
and return the value given to rollback
as {:error, value}
.
A successful transaction returns the value returned by the function
wrapped in a tuple as {:ok, value}
.
If transaction/2
is called inside another transaction, the function
is simply executed, without wrapping the new transaction call in any
way. If there is an error in the inner transaction and the error is
rescued, or the inner transaction is rolled back, the whole outer
transaction is marked as tainted, guaranteeing nothing will be committed.
Use with Ecto.Multi
Besides functions transaction can be used with an Ecto.Multi struct.
Transaction will be started, all operations applied and in case of
success committed returning {:ok, changes}
. In case of any errors
the transaction will be rolled back and
{:error, failed_operation, failed_value, changes_so_far}
will be
returned.
You can read more about using transactions with Ecto.Multi
as well as
see some examples in the Ecto.Multi
documentation.
Options
See the “Shared options” section at the module documentation.
Examples
MyRepo.transaction(fn ->
MyRepo.update!(%{alice | balance: alice.balance - 10})
MyRepo.update!(%{bob | balance: bob.balance + 10})
end)
# Roll back a transaction explicitly
MyRepo.transaction(fn ->
p = MyRepo.insert!(%Post{})
if not Editor.post_allowed?(p) do
MyRepo.rollback(:posting_not_allowed)
end
end)
# With Ecto.Multi
Ecto.Multi.new
|> Ecto.Multi.insert(%Post{})
|> MyRepo.transaction
Specs
update(Ecto.Changeset.t, Keyword.t) ::
{:ok, Ecto.Schema.t} |
{:error, Ecto.Changeset.t}
Updates a changeset using its primary key.
A changeset is required as it is the only for mechanism for tracking dirty changes.
If the struct has no primary key, Ecto.NoPrimaryKeyFieldError
will be raised.
It returns {:ok, struct}
if the struct has been successfully
updated or {:error, changeset}
if there was a validation
or a known constraint error.
Options
Besides the “Shared options” section at the module documentation, it accepts:
:force
- By default, if there are no changes in the changeset,update!/2
is a no-op. By setting this option to true, update callbacks will always be executed, even if there are no changes (including timestamps).
Example
post = MyRepo.get!(Post, 42)
post = Ecto.Changeset.change post, title: "New title"
case MyRepo.update post do
{:ok, struct} -> # Updated with success
{:error, changeset} -> # Something went wrong
end
Specs
update!(Ecto.Schema.t, Keyword.t) ::
Ecto.Schema.t |
no_return
Same as update/2
but returns the struct or raises if the changeset is invalid.
Specs
update_all(queryable :: Ecto.Queryable.t, updates :: Keyword.t, opts :: Keyword.t) ::
{integer, nil | [term]} |
no_return
Updates all entries matching the given query with the given values.
It returns a tuple containing the number of entries and any returned result as second element. If the database does not support RETURNING in UPDATE statements or no return result was selected, the second element will be nil.
Keep in mind this update_all
will not update autogenerated
fields like the updated_at
columns.
See Ecto.Query.update/3
for update operations that can be
performed on fields.
Options
:returning
- selects which fields to return. Whentrue
, returns all fields in the given struct. May be a list of fields, where a struct is still returned but only with the given fields. Orfalse
, where nothing is returned (the default). This option is not supported by all databases.
See the “Shared options” section at the module documentation for remaining options.
Examples
MyRepo.update_all(Post, set: [title: "New title"])
MyRepo.update_all(Post, inc: [visits: 1])
from(p in Post, where: p.id < 10)
|> MyRepo.update_all(set: [title: "New title"])
from(p in Post, where: p.id < 10, update: [set: [title: "New title"]])
|> MyRepo.update_all([])