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

//
        // 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

    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

      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