Postgrex v0.7.0 → Overview → Postgrex → Connection

Postgrex.Connection

Summary
Functions

Main API for Postgrex. This module handles the connection to postgres.

Source

Summary↑

listen!(pid, channel, opts \\ [])	Listens to an asynchronous notification channel `channel`. See `listen/2`
listen(pid, channel, opts \\ [])	Listens to an asynchronous notification channel using the `LISTEN` command. A message `{:notification, connection_pid, ref, channel, payload}` will be sent to the calling process when a notification is received
parameters(pid, opts \\ [])	Returns a cached map of connection parameters
query!(pid, statement, params, opts \\ [])	Runs an (extended) query and returns the result or raises `Postgrex.Error` if there was an error. See `query/3`
query(pid, statement, params, opts \\ [])	Runs an (extended) query and returns the result as `{:ok, %Postgrex.Result{}}` or `{:error, %Postgrex.Error{}}` if there was an error. Parameters can be set in the query as `$1` embedded in the query string. Parameters are given as a list of elixir values. See the README for information on how Postgrex encodes and decodes elixir values by default. See `Postgrex.Result` for the result data
start_link(opts)	Start the connection process and connect to postgres
stop(pid, opts \\ [])	Stop the process and disconnect
unlisten!(pid, ref, opts \\ [])	Stops listening on the given channel by passing the reference returned from `listen/2`
unlisten(pid, ref, opts \\ [])	Stops listening on the given channel by passing the reference returned from `listen/2`

Functions

listen(pid, channel, opts \\ [])

(function) # ↑

Specs:

listen(pid, String.t, Keyword.t) :: {:ok, reference} | {:error, Postgrex.Error.t}

Listens to an asynchronous notification channel using the LISTEN command. A message {:notification, connection_pid, ref, channel, payload} will be sent to the calling process when a notification is received.

Options

:timeout - Call timeout (default: infinity)

Source

listen!(pid, channel, opts \\ [])

(function) # ↑

Specs:

listen!(pid, String.t, Keyword.t) :: reference

Listens to an asynchronous notification channel channel. See listen/2.

Source

parameters(pid, opts \\ [])

(function) # ↑

Specs:

parameters(pid, Keyword.t) :: %{}

Returns a cached map of connection parameters.

Options

:timeout - Call timeout (default: infinity)

Source

query(pid, statement, params, opts \\ [])

(function) # ↑

Specs:

query(pid, iodata, list, Keyword.t) :: {:ok, Postgrex.Result.t} | {:error, Postgrex.Error.t}

Runs an (extended) query and returns the result as {:ok, %Postgrex.Result{}} or {:error, %Postgrex.Error{}} if there was an error. Parameters can be set in the query as $1 embedded in the query string. Parameters are given as a list of elixir values. See the README for information on how Postgrex encodes and decodes elixir values by default. See Postgrex.Result for the result data.

A type hinted query is run if both the options :param_types and :result_types are given. One client-server round trip can be saved by providing the types to Postgrex because the server doesn’t have to be queried for the types of the parameters and the result.

Options

:timeout - Call timeout (default: infinity)
:param_types - A list of type names for the parameters
:result_types - A list of type names for the result rows

Examples

Postgrex.Connection.query(pid, "CREATE TABLE posts (id serial, title text)", [])

Postgrex.Connection.query(pid, "INSERT INTO posts (title) VALUES ('my title')", [])

Postgrex.Connection.query(pid, "SELECT title FROM posts", [])

Postgrex.Connection.query(pid, "SELECT id FROM posts WHERE title like $1", ["%my%"])

Postgrex.Connection.query(pid, "SELECT $1 || $2", ["4", "2"],
                          param_types: ["text", "text"], result_types: ["text"])

Source

query!(pid, statement, params, opts \\ [])

(function) # ↑

Specs:

query!(pid, iodata, list, Keyword.t) :: Postgrex.Result.t

Runs an (extended) query and returns the result or raises Postgrex.Error if there was an error. See query/3.

Source

start_link(opts)

(function) # ↑

Specs:

start_link(Keyword.t) :: {:ok, pid} | {:error, Postgrex.Error.t | term}

Start the connection process and connect to postgres.

Options

:hostname - Server hostname (default: PGHOST env variable, then localhost);
:port - Server port (default: 5432);
:database - Database (required);
:username - Username (default: PGUSER env variable, then USER env var);
:password - User password (default PGPASSWORD);
:encoder - Custom encoder function;
:decoder - Custom decoder function;
:formatter - Function deciding the format for a type;
:parameters - Keyword list of connection parameters;
:timeout - Connect timeout in milliseconds (default: infinity);
:ssl - Set to true if ssl should be used (default: false);
:ssl_opts - A list of ssl options, see ssl docs;
:async_connect - Set to true if start_link should return before the connection is completed (default: false);

Function signatures

@spec encoder(info :: TypeInfo.t, default :: fun, param :: term) ::
      binary
@spec decoder(info :: TypeInfo.t, default :: fun, bin :: binary) ::
      term
@spec formatter(info :: TypeInfo.t) ::
      :binary | :text | nil

Source

stop(pid, opts \\ [])

(function) # ↑

Specs:

stop(pid, Keyword.t) :: :ok

Stop the process and disconnect.

Options

:timeout - Call timeout (default: infinity)

Source

unlisten(pid, ref, opts \\ [])

(function) # ↑

Specs:

unlisten(pid, reference, Keyword.t) :: :ok | {:error, Postgrex.Error.t}

Stops listening on the given channel by passing the reference returned from listen/2.

Options

:timeout - Call timeout (default: infinity)

Source

unlisten!(pid, ref, opts \\ [])

(function) # ↑

Specs:

unlisten!(pid, reference, Keyword.t) :: :ok

Stops listening on the given channel by passing the reference returned from listen/2.

Source