连接失败：** (Postgrex.Error) FATAL (invalid_catalog_name): 数据库 "api_example_dev" 不存在

Question

我正在使用 Phoenix 创建一个简单的 API Rest。执行命令时出现以下错误：mix ecto.migrate

22:25:14.197 [error] Postgrex.Protocol (#PID<0.193.0>) failed to connect: ** (Postgrex.Error) FATAL (invalid_catalog_name): database "api_example_dev" does not exist
** (DBConnection.ConnectionError) connection not available because of disconnection
    (db_connection) lib/db_connection.ex:934: DBConnection.checkout/2
    (db_connection) lib/db_connection.ex:750: DBConnection.run/3
    (db_connection) lib/db_connection.ex:1141: DBConnection.run_meter/3
    (db_connection) lib/db_connection.ex:592: DBConnection.prepare_execute/4
    (ecto) lib/ecto/adapters/postgres/connection.ex:91: Ecto.Adapters.Postgres.Connection.execute/4
    (ecto) lib/ecto/adapters/sql.ex:235: Ecto.Adapters.SQL.sql_call/6
    (ecto) lib/ecto/adapters/sql.ex:185: Ecto.Adapters.SQL.query!/5
    (ecto) lib/ecto/adapters/postgres.ex:71: Ecto.Adapters.Postgres.execute_ddl/3
    (ecto) lib/ecto/migrator.ex:43: Ecto.Migrator.migrated_versions/2
    (ecto) lib/ecto/migrator.ex:142: Ecto.Migrator.run/4
    (ecto) lib/mix/tasks/ecto.migrate.ex:84: anonymous fn/4 in Mix.Tasks.Ecto.Migrate.run/2
    (elixir) lib/enum.ex:737: Enum."-each/2-lists^foreach/1-0-"/2
    (elixir) lib/enum.ex:737: Enum.each/2
    (mix) lib/mix/task.ex:314: Mix.Task.run_task/3
    (mix) lib/mix/cli.ex:80: Mix.CLI.run_task/2
    (elixir) lib/code.ex:677: Code.require_file/2

当我运行 'mix test' 时，我得到：

Generated api_example app
** (Mix) The database for ApiExample.Repo couldn't be created: exited in: :gen_server.call(#PID<0.2449.0>, {:checkout, #Reference<0.2107810362.96468993.2762>, true, 15000}, 5000)
    ** (EXIT) time out

22:24:29.587 [error] Task #PID<0.2448.0> started from #PID<0.74.0> terminating
** (stop) exited in: :gen_server.call(#PID<0.2449.0>, {:checkout, #Reference<0.2107810362.96468993.2762>, true, 15000}, 5000)
    ** (EXIT) time out
    (db_connection) lib/db_connection/connection.ex:54: DBConnection.Connection.checkout/2
    (db_connection) lib/db_connection.ex:928: DBConnection.checkout/2
    (db_connection) lib/db_connection.ex:750: DBConnection.run/3
    (db_connection) lib/db_connection.ex:1141: DBConnection.run_meter/3
    (db_connection) lib/db_connection.ex:592: DBConnection.prepare_execute/4
    lib/ecto/adapters/postgres/connection.ex:91: Ecto.Adapters.Postgres.Connection.execute/4
    lib/ecto/adapters/postgres.ex:203: anonymous fn/2 in Ecto.Adapters.Postgres.run_query/2
    (elixir) lib/task/supervised.ex:88: Task.Supervised.do_apply/2
Function: #Function<4.100334649/0 in Ecto.Adapters.Postgres.run_query/2>

文件config/dev.exs:

# Configure your database
config :api_example, ApiExample.Repo,
  adapter: Ecto.Adapters.Postgres,
  username: "postgres",
  password: "postgres",
  database: "api_example_dev",
  hostname: "localhost",
  pool_size: 10

Answer 1

您需要运行 mix ecto.create，因为现在没有要迁移的数据库。完成后，您可以运行 mix ecto.migrate 它将执行迁移。要查看所有混合命令的列表，请使用 mix help。以下是当前可用的 ecto 任务列表：

mix ecto                 # Prints Ecto help information
mix ecto.create          # Creates the repository storage
mix ecto.drop            # Drops the repository storage
mix ecto.dump            # Dumps the repository database structure
mix ecto.gen.migration   # Generates a new migration for the repo
mix ecto.gen.repo        # Generates a new repository
mix ecto.load            # Loads previously dumped database structure
mix ecto.migrate         # Runs the repository migrations
mix ecto.migrations      # Displays the repository migration status
mix ecto.rollback        # Rolls back the repository migrations

如果您使用的是 postgresql，如果以上内容不清楚，您可以安全地假设术语 repository storage 表示 database。

如果mix ecto.create 失败，则意味着postgresql 未运行ning 或未安装。

要查看它是否运行ning，请尝试：

ps auxwww | grep postgres

您应该会看到如下内容：

username 952 0.0 0.0 2656344 388 ?? S 19Apr18 0:47.05 /Applications/Postgres.app/Contents/Versions/9.6/bin/postgres -D /Users/username/Library/Application Support/Postgres/var-9.6

如果没有（请参阅与上述类似的内容），则需要启动或安装它（如果没有）。

在 MacOS 上，我强烈推荐 Heroku 的 PostgresApp (https://postgresapp.com/) 而不是自制软件或系统 postgresql。

如果您在评论中告诉我 OS 如果上述方法不起作用，我会用 OS 说明更新我的答案。

连接失败：** (Postgrex.Error) FATAL (invalid_catalog_name): 数据库 "api_example_dev" 不存在

failed to connect: ** (Postgrex.Error) FATAL (invalid_catalog_name): database "api_example_dev" does not exist

elixir

ecto

phoenix-framework