如何在Entity Framework Core 1.0 RTM中关闭级联删除

时间：2016-11-01 08:18:51

标签： c# sql entity-framework asp.net-core-mvc entity-framework-core

嗨我有实体框架核心1.0 RTM和SQL服务器的MVC 6应用程序，当我尝试生成数据库表时，我得到了＃34;引入FOREIGN KEY约束可能导致循环或多个级联路径＆＃34;错误。

我的模型类如下：

类别模型：

@Entity
public class MyEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", updatable = false, nullable = false)
    private Long id;

    @Column
    private LocalDate date;

    @Column
    private LocalDateTime dateTime;

    ...

}

电台型号：

 public class Category
{
    public Category()
    {
        this.VariableSettings = new List<VariableSetting>();
    }
    public int CategoryId { get; set; }

    public string CategoryName { get; set; }

    public List<VariableSetting> VariableSettings { get; set; }

    public List<Station> Stations { get; set; }
}

VariableRecord模型：

 public class Station
{
    public int StationId { get; set; }
    public string StationName { get; set; }

    public double? Longitude { get; set; }
    public double? Latitude { get; set; }

    public List<VariableRecord> VariableRecords { get; set; }

    public int CategoryID { get; set; }
    public Category Category { get; set; }
}

VariableSetting Model：

 public class VariableRecord
{
    [Key]
    public int VariableRecordId { get; set; }
    public double Value { get; set; }
    public DateTime RecordDate { get; set; }

    public int StationId { get; set; }
    public Station Station { get; set; }

    public int VarSettingId{ get; set; }
    public virtual VariableSetting VariableSetting { get; set; }
}

变量模型：

public class VariableSetting
{
    [Key]
    public int VarSettingId { get; set; }
    public int Sequence { get; set; }
    public double? MinimumValue { get; set; }
    public double? MaximumValue { get; set; }

    public int CategoryId { get; set; }
    public virtual Category Category { get; set; }

    public int VariableId { get; set; }
    public Variable Variable { get; set; }

    public List<VariableRecord> VariableRecords { get; set; }
}

所以，在我的代码中有Cascade删除路由类别 - >＆gt; Station-＆gt; VariableRecord和Category-＆gt; VariableSetting-＆gt; VariableRecord，所以我试图通过路径分类 - ＆gt; VariableSetting-＆gt;使用Fluent API的上下文类中的VariableRecord如下：

 public class Variable
{
    public int VariableId { get; set; }

    public string VariableName { get; set; }

    public string Description { get; set; }

    public string Unit { get; set; }

    public List<VariableSetting> VariableSettings { get; set; }
}

但是我仍然如下：

  

System.Data.SqlClient.SqlException（0x80131904）：FOREIGN简介   关键约束＆＃39; FK_VariableSetting_Category_CategoryId＆＃39;桌子上   ＆＃39; VariableSetting＆＃39;可能导致循环或多个级联路径。指定   ON DELETE NO ACTION或ON UPDATE NO ACTION，或修改其他FOREIGN   关键约束。

我被困在这些代码上几天但仍无处可去，请帮忙！

2 个答案:

答案 0 :(得分：3)

使用DeleteBehavior.Restrict代替DeleteBehavior.Cascade。

您已经拥有多个级联路径，因此如果您需要（确定，您需要）在其中一个上禁用级联 - 请使用DeleteBehavior.Restrict。

答案 1 :(得分：0)

如果您遵循命名约定，您只需要类定义和一些注释（使用EF Core 1.0.1）

public class Category
{
    [Key]
    public int Id { get; set; }
    [Required]
    public string Name { get; set; }

    //[InverseProperty( nameof( VariableSetting.Category ) )]
    public virtual ICollection<VariableSetting> VariableSettings { get; set; }
        = new List<VariableSetting>();

    //[InverseProperty( nameof( Station.Category ) )]
    public virtual ICollection<Station> Stations { get; set; } 
        = new List<Station>();
}

public class Station
{
    [Key]
    public int Id { get; set; }
    [Required]
    public string Name { get; set; }
    public double? Longitude { get; set; }
    public double? Latitude { get; set; }

    //[InverseProperty( nameof( VariableRecord.Station ) )]
    public virtual ICollection<VariableRecord> VariableRecords { get; set; }
        = new List<VariableRecord>();

    [Required]
    public int CategoryId { get; set; }

    //[ForeignKey( nameof( CategoryId ) )]
    public virtual Category Category { get; set; }
}

public class VariableRecord
{
    [Key]
    public int Id { get; set; }
    public double Value { get; set; }
    public DateTime RecordDate { get; set; }

    [Required]
    public int StationId { get; set; }

    //[ForeignKey( nameof( StationId ) )]
    public virtual Station Station { get; set; }

    [Required]
    public int VariableSettingId { get; set; }

    //[ForeignKey( nameof( VariableSettingId ) )]
    public virtual VariableSetting VariableSetting { get; set; }
}

public class VariableSetting
{
    [Key]
    public int Id { get; set; }
    public int Sequence { get; set; }
    public double? MinimumValue { get; set; }
    public double? MaximumValue { get; set; }

    [Required]
    public int CategoryId { get; set; }

    //[ForeignKey( nameof( CategoryId ) )]
    public virtual Category Category { get; set; }

    [Required]
    public int VariableId { get; set; }

    //[ForeignKey( nameof( VariableId ) )]
    public virtual Variable Variable { get; set; }

    //[InverseProperty( nameof( VariableRecord.VariableSetting ) )]
    public virtual ICollection<VariableRecord> VariableRecords { get; set; }
        = new List<VariableRecord>();
}

public class Variable
{
    [Key]
    public int Id { get; set; }

    [Required]
    public string Name { get; set; }
    public string Description { get; set; }
    public string Unit { get; set; }

    //[InverseProperty( nameof( VariableSetting.Variable ) )]
    public virtual ICollection<VariableSetting> VariableSettings { get; set; }
        = new List<VariableSetting>();
}

如果您想要其他名称，请取消注释所有注释并修复名称。

创建的（SQLite）sql结构是

PRAGMA foreign_keys = false;

-- ----------------------------
--  Table structure for "Categories"
-- ----------------------------
DROP TABLE IF EXISTS "Categories";
CREATE TABLE "Categories" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_Categories" PRIMARY KEY AUTOINCREMENT,
    "Name" TEXT NOT NULL
);

-- ----------------------------
--  Table structure for "Stations"
-- ----------------------------
DROP TABLE IF EXISTS "Stations";
CREATE TABLE "Stations" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_Stations" PRIMARY KEY AUTOINCREMENT,
    "CategoryId" INTEGER NOT NULL,
    "Latitude" REAL,
    "Longitude" REAL,
    "Name" TEXT NOT NULL,
    CONSTRAINT "FK_Stations_Categories_CategoryId" FOREIGN KEY ("CategoryId") REFERENCES "Categories" ("Id") ON DELETE CASCADE
);

-- ----------------------------
--  Table structure for "Variable"
-- ----------------------------
DROP TABLE IF EXISTS "Variable";
CREATE TABLE "Variable" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_Variable" PRIMARY KEY AUTOINCREMENT,
    "Description" TEXT,
    "Name" TEXT NOT NULL,
    "Unit" TEXT
);

-- ----------------------------
--  Table structure for "VariableRecord"
-- ----------------------------
DROP TABLE IF EXISTS "VariableRecord";
CREATE TABLE "VariableRecord" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_VariableRecord" PRIMARY KEY AUTOINCREMENT,
    "RecordDate" TEXT NOT NULL,
    "StationId" INTEGER NOT NULL,
    "Value" REAL NOT NULL,
    "VariableSettingId" INTEGER NOT NULL,
    CONSTRAINT "FK_VariableRecord_Stations_StationId" FOREIGN KEY ("StationId") REFERENCES "Stations" ("Id") ON DELETE CASCADE,
    CONSTRAINT "FK_VariableRecord_VariableSetting_VariableSettingId" FOREIGN KEY ("VariableSettingId") REFERENCES "VariableSetting" ("Id") ON DELETE CASCADE
);

-- ----------------------------
--  Table structure for "VariableSetting"
-- ----------------------------
DROP TABLE IF EXISTS "VariableSetting";
CREATE TABLE "VariableSetting" (
    "Id" INTEGER NOT NULL CONSTRAINT "PK_VariableSetting" PRIMARY KEY AUTOINCREMENT,
    "CategoryId" INTEGER NOT NULL,
    "MaximumValue" REAL,
    "MinimumValue" REAL,
    "Sequence" INTEGER NOT NULL,
    "VariableId" INTEGER NOT NULL,
    CONSTRAINT "FK_VariableSetting_Categories_CategoryId" FOREIGN KEY ("CategoryId") REFERENCES "Categories" ("Id") ON DELETE CASCADE,
    CONSTRAINT "FK_VariableSetting_Variable_VariableId" FOREIGN KEY ("VariableId") REFERENCES "Variable" ("Id") ON DELETE CASCADE
);

-- ----------------------------
--  Indexes structure for table "Stations"
-- ----------------------------
CREATE INDEX "IX_Stations_CategoryId" ON "Stations" ("CategoryId");

-- ----------------------------
--  Indexes structure for table "VariableRecord"
-- ----------------------------
CREATE INDEX "IX_VariableRecord_StationId" ON "VariableRecord" ("StationId");
CREATE INDEX "IX_VariableRecord_VariableSettingId" ON "VariableRecord" ("VariableSettingId");

-- ----------------------------
--  Indexes structure for table "VariableSetting"
-- ----------------------------
CREATE INDEX "IX_VariableSetting_CategoryId" ON "VariableSetting" ("CategoryId");
CREATE INDEX "IX_VariableSetting_VariableId" ON "VariableSetting" ("VariableId");

PRAGMA foreign_keys = true;

如您所见，无需关闭级联删除：o）

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