Question

我正在尝试与EF6建立一对多关系

这是我的实体。

图书：

public class Book
{
    public int BookId { get; set; }
    public string BookName { get; set; }
}

发布者：

public class Publisher
{
    public int PublisherId { get; set; }
    public string PublisherName { get; set; }
    public ICollection<Book> Books { get; set; }
}

上下文：

[DbConfigurationType(typeof(MySqlEFConfiguration))]
public class MyContext : DbContext
{
    public MyContext() : base("name=MySqlDbConnectionString")
    {
        Database.SetInitializer(new DropCreateDatabaseAlways<MyContext>());
    }

    public DbSet<Publisher> Publishers { get; set; }
    public DbSet<Book> Books { get; set; }
}

程序：

static void Main(string[] args)
    {
        using (MyContext entities = new MyContext())
        {
            Book user = new Book() { BookName = "gdsag" };
            entities.Books.Add(user);
            entities.SaveChanges();
        }
    }

该问题已用于自动创建数据库。但是当我运行它时，出现以下错误：

MySql.Data.MySqlClient.MySqlException：'不正确使用空间/全文/哈希索引和显式索引顺序'

我正在使用EF 6.2
MySql.Data 6.9
MySql.Data.Entity 6.9

任何想法我在做什么错误？

预先感谢

修改：这些是生成sql命令

create table `Books` (`BookId` int not null  auto_increment ,`BookName` longtext,`Publisher_PublisherId` int,primary key ( `BookId`) ) engine=InnoDb auto_increment=0
-- Executing at 7/2/2018 11:02:32 PM +03:00
-- Completed in 52 ms with result: 0

create table `Publishers` (`PublisherId` int not null  auto_increment ,`PublisherName` longtext,primary key ( `PublisherId`) ) engine=InnoDb auto_increment=0
-- Executing at 7/2/2018 11:02:32 PM +03:00
-- Completed in 49 ms with result: 0

CREATE index  `IX_Publisher_PublisherId` on `Books` (`Publisher_PublisherId` DESC) using HASH
-- Executing at 7/2/2018 11:02:32 PM +03:00
-- Failed in 2 ms with error: Incorrect usage of spatial/fulltext/hash index and explicit index order

Disposed transaction at 7/2/2018 11:02:32 PM +03:00

Answer 1

我最近将.NET的sql客户端库更新为8.X。我正在构建一个框架应用程序（不是CORE），并且我主要使用EF实体的数据注释（不是流利的）配置，但遇到了同样的问题。数据上下文不会初始化，并且会生成错误“空间/全文/哈希索引和显式索引顺序的错误使用”。事实证明，MySQL开发人员似乎忽略了这种sceniaro测试套件。我最终在MySqlMigrationSqlGenerator中重写了CreateIndexOperation生成器，并将默认的“ using HASH”替换为“ using BTREE”。现在我的索引是正确创建的外键关系。

Answer 2

当然，我要做的是从MySqlMigrationSqlGenerator继承一个类，然后在DbMigrationsConfiguration处理程序中激活了该类。首先列出该类，并提供迁移处理程序的摘录

public class FixedMySqlMigrationSqlGenerator : MySqlMigrationSqlGenerator
{
    public FixedMySqlMigrationSqlGenerator()
        :base()
    {
    }

    /// <summary>
    /// we want BTREE because HASH is not correct for normal Keys on MySQL 8
    /// </summary>
    /// <param name="op"></param>
    /// <returns></returns>
    protected override MigrationStatement Generate(CreateIndexOperation op)
    {
        MigrationStatement migrationStatement = base.Generate(op);
        System.Diagnostics.Trace.WriteLine(migrationStatement.Sql);
        string fubarSql = migrationStatement.Sql.TrimEnd();

        if(fubarSql.EndsWith("using HASH",StringComparison.OrdinalIgnoreCase))
        {
            string modSql = fubarSql.Replace("using HASH", " using BTREE");
            migrationStatement.Sql = modSql;
        }
        return migrationStatement;
    }


}

我也有一个dbmigrationsconfiguration类

public sealed class LogDataMigration : DbMigrationsConfiguration<LogDataContext>
{
    public const string CONTEXT_KEY = "BalsamicSoftware.LogData";
    private static readonly HashSet<string> _InitializedConnections = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

    private static readonly object _LockProxy = new object();

    public LogDataMigration()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
        ContextKey = CONTEXT_KEY;
        SetSqlGenerator("MySql.Data.MySqlClient", new FixedMySqlMigrationSqlGenerator());

    }
}

通过静态调用

激活迁移配置类

Database.SetInitializer<LogDataContext>(new MigrateDatabaseToLatestVersion<LogDataContext, LogDataMigration>(true));

因此，这是三个步骤，首先创建一个迁移配置（如果您还没有的话）。实现sql生成器，然后从您的迁移配置中调用sql生成器。

EF6-空间/全文/哈希索引和显式索引顺序的错误使用

2 个答案: