@callback all(query :: Ecto.Query.t()) :: iodata()

Receives a query and must return a SELECT query.

@callback child_spec(options :: Keyword.t()) :: {module(), Keyword.t()}

Receives options and returns DBConnection supervisor child specification.

@callback ddl_logs(result :: term()) :: [
  {Logger.level(), Logger.message(), Logger.metadata()}
]

Receives a query result and returns a list of logs.

@callback delete(
  prefix :: String.t(),
  table :: String.t(),
  filters :: [atom()],
  returning :: [atom()]
) ::
  iodata()

Returns a DELETE for the filters returning the given returning.

@callback delete_all(query :: Ecto.Query.t()) :: iodata()

Receives a query and must return a DELETE query.

@callback execute(connection(), cached(), params(), options :: Keyword.t()) ::
  {:ok, cached(), term()} | {:ok, term()} | {:error | :reset, Exception.t()}

Executes a cached query.

@callback execute_ddl(command :: Ecto.Adapter.Migration.command()) ::
  String.t() | [iodata()]

Receives a DDL command and returns a query that executes it.

@callback explain_query(
  connection(),
  query :: String.t(),
  params :: Keyword.t(),
  opts :: Keyword.t()
) ::
  {:ok, term()} | {:error, Exception.t()}

Executes an EXPLAIN query or similar depending on the adapter to obtains statistics of the given query.

Receives the connection, query, params for the query, and all opts including those related to the EXPLAIN statement and shared opts.

Must execute the explain query and return the result.

@callback insert(
  prefix :: String.t(),
  table :: String.t(),
  header :: [atom()],
  rows :: [[atom() | nil]],
  on_conflict :: Ecto.Adapter.Schema.on_conflict(),
  returning :: [atom()],
  placeholders :: [term()]
) :: iodata()

Returns an INSERT for the given rows in table returning the given returning.

@callback prepare_execute(
  connection(),
  name(),
  statement(),
  params(),
  options :: Keyword.t()
) ::
  {:ok, cached(), term()} | {:error, Exception.t()}

Prepares and executes the given query with DBConnection.

@callback query(connection(), statement(), params(), options :: Keyword.t()) ::
  {:ok, term()} | {:error, Exception.t()}

Runs the given statement as a query.

@callback query_many(connection(), statement(), params(), options :: Keyword.t()) ::
  {:ok, term()} | {:error, Exception.t()}

Runs the given statement as a multi-result query.

@callback stream(connection(), statement(), params(), options :: Keyword.t()) :: Enum.t()

Returns a stream that prepares and executes the given query with DBConnection.

@callback table_exists_query(table :: String.t()) :: {iodata(), [term()]}

Returns a queryable to check if the given table exists.

@callback to_constraints(exception :: Exception.t(), options :: Keyword.t()) ::
  Keyword.t()

Receives the exception returned by query/4.

The constraints are in the keyword list and must return the constraint type, like :unique, and the constraint name as a string, for example:

[unique: "posts_title_index"]

Must return an empty list if the error does not come from any constraint.

@callback update(
  prefix :: String.t(),
  table :: String.t(),
  fields :: [atom()],
  filters :: [atom()],
  returning :: [atom()]
) :: iodata()

Returns an UPDATE for the given fields in table filtered by filters returning the given returning.

@callback update_all(query :: Ecto.Query.t()) :: iodata()

Receives a query and values to update and must return an UPDATE query.