EF：不正确使用空间/全文/哈希索引和显式索引顺序

Question

我在我的WEB Api项目中使用了Entity Framework。我使用代码优先迁移。

事情是：进行初始迁移并尝试更新数据库后，出现此错误

不正确使用空间/全文/哈希索引和显式索引顺序

这是由更新数据库中的此SQL命令引起的：

create table `Articles` 

(

 `articleId` int not null  auto_increment ,

 `title` longtext not null ,

 `digest` longtext,

 `content` longtext not null ,

 `imgLink` longtext not null ,

 `releaseDate` datetime,

 `userId` int not null ,

  primary key ( `articleId`)

) engine=InnoDb auto_increment=0

  CREATE index  `IX_userId` on `Articles` (`userId` DESC) using HASH

SQL命令是从迁移中的以下代码生成的：

CreateTable(

            "dbo.Articles",

            c => new

                {

                    articleId = c.Int(nullable: false, identity: true),

                    title = c.String(nullable: false, unicode: false),

                    digest = c.String(unicode: false),

                    content = c.String(nullable: false, unicode: false),

                    imgLink = c.String(nullable: false, unicode: false),

                    releaseDate = c.DateTime(precision: 0),

                    userId = c.Int(nullable: false),

                })

            .PrimaryKey(t => t.articleId)

            .ForeignKey("dbo.Users", t => t.userId, cascadeDelete: true)

            .Index(t => t.userId);

似乎在创建索引时出现DESC和HASH会导致此错误。关于如何更改生成的sql索引创建的任何想法，使其与简单的索引一起使用？或者只是简单地绕过此错误，以便我的更新数据库可以通过？谢谢 ！

Answer 1

解决了。在您的迁移文件中，用如下的sql命令替换.Index条目CreateTable(&nbsp; &nbsp; &nbsp; &nbsp; "dbo.Articles",&nbsp; &nbsp; &nbsp; &nbsp; c => new&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; articleId = c.Int(nullable: false, identity: true),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; title = c.String(nullable: false, unicode: false),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; digest = c.String(unicode: false),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; content = c.String(nullable: false, unicode: false),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; imgLink = c.String(nullable: false, unicode: false),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; releaseDate = c.DateTime(precision: 0),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; userId = c.Int(nullable: false),&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; })&nbsp; &nbsp; &nbsp; &nbsp; .PrimaryKey(t => t.articleId)&nbsp; &nbsp; &nbsp; &nbsp; .ForeignKey("dbo.Users", t => t.userId, cascadeDelete: true)&nbsp; &nbsp; &nbsp; &nbsp; .Index(t => t.userId); // REMOVE THIS在Up（）方法的底部添加相应的SQL命令（对于每个索引）Sql("CREATE index `IX_userId` on `Articles` (`userId` DESC)");然后我为DataReaders添加的问题与MySQL连接器有关。MySQL连接器不支持多个活动连接。要处理此问题，如果您的控制器中有此命令public IEnumerable<Article> GetArticles(){&nbsp; &nbsp; return db.Articles;}现在应该是public IEnumerable<Article> GetArticles(){&nbsp; &nbsp; return db.Articles.ToList(); // ToList() will manage the request to work with only ONE data reader,&nbsp;}如果您不知道如何将.Index（）转换为SQL命令，只需update-database -verbose并且所有的SQL命令将显示