core ef配置连接字符串

appsettings.json里边

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "SchoolContext": "Server=.;Database=SchoolContext;uid=sa;password=123456",
    "SchoolContext2": "Server=(localdb)\\mssqllocaldb;Database=SchoolContext;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}