解决 Mysql下使用EF Code First 指定表Engine无效的思路

用Code First创建表时 用 update-database -verbose 查看脚本 可以发现所有的表的默认Engine都是InnoDB

因为业务要求 有张表的Engine是MyISAM.

到Migration的up方法中修改

未修改前的代码如下:

?

CreateTable(

    "Tests",

    c => new

        {

            ID = c.Int(nullable: false),

            Name = c.String(unicode: false),

    })

    .PrimaryKey(t => t.ID);

想办法从CreateTable方法入手 查看基类CreateTable方法说明

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//

        // 摘要:

        //     Adds an operation to create a new table.

        //

        // 参数:

        //   name:

        //     The name of the table. Schema name is optional, if no schema is specified

        //     then dbo is assumed.

        //

        //   columnsAction:

        //     An action that specifies the columns to be included in the table.  i.e. t

        //     => new { Id = t.Int(identity: true), Name = t.String() }

        //

        //   anonymousArguments:

        //     Additional arguments that may be processed by providers. Use anonymous type

        //     syntax to specify arguments e.g. 'new { SampleArgument = "MyValue" }'.

        //

        // 类型参数:

        //   TColumns:

        //     The columns in this create table operation. You do not need to specify this

        //     type, it will be inferred from the columnsAction parameter you supply.

        //

        // 返回结果:

        //     An object that allows further configuration of the table creation operation.

        protected internal TableBuilder<TColumns> CreateTable<TColumns>(string name, Func<ColumnBuilder, TColumns> columnsAction, object anonymousArguments = null);

好了 anonymousArguments参数是我可以用的 根据说明 本以为应该是 new { Engine = "MyISAM" }

修改代码后 如下:

?

CreateTable(

    "Tests",

    c => new

        {

            ID = c.Int(nullable: false),

            Name = c.String(unicode: false),

        }, new { Engine = "MyISAM" })

    .PrimaryKey(t => t.ID);

再update-database -verbose 看脚本 结果还是一样 默认InnoDB的 

当时估计 可能是PropertyName 区分大小写 又试了 new { engine = "MyISAM" } new { ENGINE = "MyISAM" }

还是不行. nnd mysql关于code first的资料太少了 官网上都是些简单的demo

没办法 去下载Connector的源码 自己看看 源码下载点击这里

打开项目MySql.Data.Entity中的MySqlMigrationSqlGenerator.cs

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protected virtual MigrationStatement Generate(CreateTableOperation op)

{

  StringBuilder sb = new StringBuilder();

  if (generatedTables == null)

    generatedTables = new List<string>();

 

  if (!generatedTables.Contains(op.Name))

  {

    generatedTables.Add(op.Name);

  }

  sb.Append("create table " + "`" + op.Name + "`" + " (");

 

  //columns

  sb.Append(string.Join(",", op.Columns.Select(c => "`" + c.Name + "` " + Generate(c))));

 

  if (op.PrimaryKey != null && !sb.ToString().Contains("primary key"))

  {

    sb.Append(",");

    sb.Append("primary key ( " + string.Join(",", op.PrimaryKey.Columns.Select(c => "`" + c + "`")) + ") ");

  }

 

    sb.Append(") engine=InnoDb auto_increment=0");

 

    return new MigrationStatement() { Sql = sb.ToString() };

}

搞了半天 原来根本没有考虑到指定Engine的情况.

到这里就没办法继续了 我只是提供思路 修改源码

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if (op.AnonymousArguments.ContainsKey("Engine"))

{

    sb.Append(string.Format(") engine={0} auto_increment=0", op.AnonymousArguments["Engine"]));

}

else

{

    sb.Append(") engine=InnoDb auto_increment=0");

}

然后再用 new { Engine = "MyISAM" }就没有问题了

稍后我会向mysql 提交bug报告 各位同学也可以等待mysql来修复　　

已经向mysql提交功能缺失bug报告 Bug #68237