EF Core：更新数据库错误：关系“所有者”已经存在

Question

I try to add migration:

dotnet ef migrations add InitialCreate

and then update the database:

dotnet ef database update

But, I get an error:

Build started...
Build succeeded.
[21:59:12 INF] OnConfigure finish
Applying migration '20201029182606_InitialCreate'.

Failed executing DbCommand (7ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
CREATE TABLE "Owner" (
"Id" integer NOT NULL GENERATED BY DEFAULT AS IDENTITY,
reputation integer NOT NULL, user_id integer NOT NULL,
user_type text NULL,
profile_image text NULL,
display_name text NULL,
link text NULL,
accept_rate integer NULL,
CONSTRAINT "PK_Owner" PRIMARY KEY ("Id")
);

Npgsql.PostgresException (0x80004005): 42P07: relation "Owner" already exists

at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location ---
at Npgsql.NpgsqlConnector.<>c__DisplayClass160_0.<g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location ---
at Npgsql.NpgsqlDataReader.NextResult(Boolean async, Boolean isConsuming)
at Npgsql.NpgsqlDataReader.NextResult()
at Npgsql.NpgsqlCommand.ExecuteReaderAsync(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
at Npgsql.NpgsqlCommand.ExecuteNonQuery(Boolean async, CancellationToken cancellationToken)
at Npgsql.NpgsqlCommand.ExecuteNonQuery()

Exception data:
Severity: ERROR
SqlState: 42P07
MessageText: relation "Owner" already exists
File: heap.c
Line: 1155
Routine: heap_create_with_catalog
42P07: relation "Owner" already exists

Here on my github i store model (and other source code of service). I remove 'EnsureCreate' code from ApplicationContext file.

How to solve this error? Thank you!

PS I remove file appsettings.json where store connetion string:

 {
"Logging": {
 "LogLevel": {
   "Default": "Information",
   "Microsoft": "Warning",
   "Microsoft.Hosting.Lifetime": "Information"
 }
},
 "AllowedHosts": "*",
 "ConnectionStrings": {
  "Questions": "Host=localhost;Port=5432;Database=questiondb;Username=postgres;Password=password"
 },
  "Tags": [
   "ef core",
   "c#",
   "asp.net core",
   "asp.net core webapi"
  ]
  }

Answer 1

In your line 38 I see a problem where you use filed but you need to use the property.

public Owner Owner { get; set; }

But you use

public Owner owner { get; set; }

and that's a problem.

Another solution: as I understand to see your problem that owner table relation already exists. So delete unnecessary relation or use Fluent Api.

Answer 2

使用 DB Management Studio 或命令行删除Owner表，然后再次运行迁移。