有人可以解释如何在 C# 中为表设置外键吗？

Question

我正在一个项目中使用 C# 在数据库中创建表，但我不知道如何创建外键。

这是我要创建的 SQL：

  CREATE TABLE FactSalesOrders
  (ProductKey int NOT NULL REFERENCES DimProduct(ProductKey),
   CustomerKey int NOT NULL REFERENCES DimCustomer(CustomerKey),
   SalespersonKey int NOT NULL REFERENCES DimSalesperson(SalepersonKey),
   OrderDateKey int NOT NULL REFERENCES DimDate(DateKey),
   OrderNo int NOT NULL,
   ItemNo int Not NULL,
   Quantity int Not NULL,
   SalesAmount money NOT NULL,
   Cost money NOT NULL
        CONSTRAINT [PK_FactSalesOrders] PRIMARY KEY NONCLUSTERED
    (
        [ProductKey],[CustomerKey],[SalespersonKey],[OrderDateKey],[OrderNo],[ItemNo]
    )
  )

例如，我只是尝试为 ProductKey 设置“REFERENCES”部分，使其引用 DimProduct 表中的 ProductKey 列。

这是我在 factTable 表中创建 ProductKey 列的代码：

    //Creating Fact Table
    Table factTable = new Table(myDatabase, "Fact Table");

    //Column One: Product Key
    Column ProductKey = new Column(factTable, "ProductKey", DataType.Int);
    ProductKey.Nullable = false;
    factTable.Columns.Add(ProductKey);

这是我尝试引用的 DimProduct 表的代码：

//Creating DimProduct
            Table DimProduct = new Table(myDatabase, "DimProduct");

            //Column One: Product Key
            Column productKey = new Column(DimProduct, "ProductKey", DataType.Int);
            productKey.Nullable = false;
            DimProduct.Columns.Add(productKey);

            //Column Two: Product Alt Key
            Column productAltKey = new Column(DimProduct, "ProductAltKey", DataType.NVarChar(10));
            productAltKey.Nullable = false;
            DimProduct.Columns.Add(productAltKey);

            //Column Three: Product Name
            Column productName = new Column(DimProduct, "ProductName", DataType.NVarChar(50));
            productName.Nullable = true;
            DimProduct.Columns.Add(productName);

            //Column Four: Product Description
            Column productDescription = new Column(DimProduct, "ProductDescription", DataType.NVarChar(100));
            productDescription.Nullable = true;
            DimProduct.Columns.Add(productDescription);

            //Column Five: Product Catagory Name
            Column productCatagoryName = new Column(DimProduct, "ProductCatagoryName", DataType.NVarChar(50));
            productCatagoryName.Nullable = true;
            DimProduct.Columns.Add(productCatagoryName);

            //Primary Key
            Index primaryKeyIndex1 = new Index(DimProduct, "PK_DimProduct");
            primaryKeyIndex1.IndexKeyType = IndexKeyType.DriPrimaryKey;
            primaryKeyIndex1.IndexedColumns.Add(new IndexedColumn(primaryKeyIndex1, "productKey"));
            DimProduct.Indexes.Add(primaryKeyIndex1);

            DimProduct.Create();

我确实找到了这个链接：LINK1

它给出了以下示例，但我无法让它工作：

//Connect to the local, default instance of SQL Server. 
            Server srv;
            srv = new Server();
            //Reference the AdventureWorks2012 database. 
            Database db;
            db = srv.Databases["AdventureWorks2012"];
            //Declare another Table object variable and reference the EmployeeDepartmentHistory table. 
            Table tbea;
            tbea = db.Tables["EmployeeDepartmentHistory", "HumanResources"];
            //Define a Foreign Key object variable by supplying the EmployeeDepartmentHistory as the parent table and the foreign key name in the constructor. 
            ForeignKey fk;
            fk = new ForeignKey(tbea, "test_foreignkey");
            //Add BusinessEntityID as the foreign key column. 
            ForeignKeyColumn fkc;
            fkc = new ForeignKeyColumn(fk, "BusinessEntityID", "BusinessEntityID");
            fk.Columns.Add(fkc);
            //Set the referenced table and schema. 
            fk.ReferencedTable = "Employee";
            fk.ReferencedTableSchema = "HumanResources";
            //Create the foreign key on the instance of SQL Server. 
            fk.Create();

任何帮助或见解将不胜感激！谢谢！

Answer 1

似乎代码太多，几乎什么都没有

在 c# 中你有你的 db 连接和默认的 db 或发出使用 mydatabase cmd

然后触发一个简单的字符串等价于

ALTER TABLE Orders
ADD FOREIGN KEY (persId)
REFERENCES Persons(persId)