Question

我正在尝试使用context.AddOrUpdate方法为数据库设定种子，但问题是我需要根据多列索引使插入的数据唯一。

[Table("climbing_grades")]
public class ClimbingGrade : EntityBase
{
    /// <summary>
    /// The name of the climbing grade, e.g.: 7a, VII, etc.
    /// </summary>
    [Index("IX_Name_GradeType", 1, IsUnique = true)]
    public string Name { get; set; }

    /// <summary>
    /// Tries to display the average difficulty of the described grade.
    /// Matching the different grades can be difficult because its always
    /// a subjective rating and there exists no norm on converting grades.
    /// </summary>
    public double Difficulty { get; set; }

    /// <summary>
    /// The type of the grade. Will be the respective region rating.
    /// e.g.: UUIA for most oft europe, YSD for USA, etc.
    /// </summary>
    [Index("IX_Name_GradeType", 2, IsUnique = true)]
    public ClimbingGradeType GradeType { get; set; }
}

目前我AddOrUpdate基于攀爬等级的Name，但现在我需要插入重复的名称。

context.ClimbingGrades.AddOrUpdate(grade => /* Compare multi column index here?*/,
    new ClimbingGrade
    {
        Name = "5a",
        Difficulty = 4.75,
        GradeType = ClimbingGradeType.FontainebleauBloc
    },
    new ClimbingGrade
    {
        Name = "5a",
        Difficulty = 4.25,
        GradeType = ClimbingGradeType.FontainebleauTraverse
    });

插入种子数据时是否可以比较多列索引？

Answer 1

您需要使用匿名类型来指定多个列。这也可以在不指定标记的情况下使用。

context.ClimbingGrades.AddOrUpdate(grade => new { grade.Name, grade.GradeType },
    new ClimbingGrade
    {
        Name = "5a",
        Difficulty = 4.75,
        GradeType = ClimbingGradeType.FontainebleauBloc
    },
    new ClimbingGrade
    {
        Name = "5a",
        Difficulty = 4.25,
        GradeType = ClimbingGradeType.FontainebleauTraverse
    });

实体框架 - 使用多列索引作为标识符的种子AddOrUpdate

1 个答案: