.netcore 遇到的一些坑_invalidoperationexception: an exception has been r

1、联合主键异常：

InvalidOperationException: Entity type '***' has composite primary key defined with data annotations. To set composite primary key, use fluent API.

解决方案：EFCore 联合主键不支持注解的方式，需要使用fluent API。

即，要把这种注解的方式

public class OtaVersion
{
    [Key, Column(Order = 0)]
    public int ProductClass { get; set; }
 
    [Key, Column(Order = 1)]
    public int ProductSku { get; set; }
 
    public int SourceType { get; set; }
}

更换为fluent API:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<OtaVersion>().HasKey(t => new { t.ProductClass, t.ProductSku });
}

2、

An exception has been raised that is likely due to a transient failure. Consider enabling transient error resiliency by adding 'EnableRetryOnFailure（）' to the 'UseMySql' call.

解决方案：这一般是连接方面的问题，确认一下连接字符串是否正确，注意port，sslMode等的设置(不区分大小写)

Server=127.0.0.1;Port=3306;Database=数据库;User ID=账户;Password=密码;Persistsecurityinfo=True;Character Set=utf8;Allow User Variables=True;SslMode=None;