NHibernate SQL创建会导致错误

Question

我有2个名为Order和Orderrow的类。 我使用NHibernate来获取它的连接。

运行NUnit来测试查询时，我得到了一个ADOException：

Logica.NHibernate.Tests.NHibernateTest.SelectAllOrdersFromSupplierNamedKnorrTest:
NHibernate.ADOException : could not execute query
[ SELECT this_.OrderId as OrderId1_1_, this_.CreatedAt as CreatedAt1_1_, this_.ShippedAt as ShippedAt1_1_, this_.ContactId as ContactId1_1_, customer2_.ContactId as ContactId0_0_, customer2_.LastName as LastName0_0_, customer2_.Initials as Initials0_0_, customer2_.Address as Address0_0_, customer2_.City as City0_0_, customer2_.Country as Country0_0_ FROM Order this_ inner join Contact customer2_ on this_.ContactId=customer2_.ContactId ]
[SQL: SELECT this_.OrderId as OrderId1_1_, this_.CreatedAt as CreatedAt1_1_, this_.ShippedAt as ShippedAt1_1_, this_.ContactId as ContactId1_1_, customer2_.ContactId as ContactId0_0_, customer2_.LastName as LastName0_0_, customer2_.Initials as Initials0_0_, customer2_.Address as Address0_0_, customer2_.City as City0_0_, customer2_.Country as Country0_0_ FROM Order this_ inner join Contact customer2_ on this_.ContactId=customer2_.ContactId]
  ----> System.Data.SqlClient.SqlException : Incorrect syntax near the keyword 'Order'.

在分析由NHibernate创建的SQL时，我注意到Order类正在破坏SQL语句，因为ORDER BY是SQL中的内部关键字。

这是NHibernate中创建的SQL：

SELECT this_.OrderId as OrderId1_1_, this_.CreatedAt as CreatedAt1_1_, this_.ShippedAt as ShippedAt1_1_, this_.ContactId as ContactId1_1_, customer2_.ContactId as ContactId0_0_, customer2_.LastName as LastName0_0_, customer2_.Initials as Initials0_0_, customer2_.Address as Address0_0_, customer2_.City as City0_0_, customer2_.Country as Country0_0_ FROM Order this_ inner join Contact customer2_ on this_.ContactId=customer2_.ContactId

我在SQL Server 2008 Management studio中将其更改为：

SELECT this_.OrderId as OrderId1_1_, this_.CreatedAt as CreatedAt1_1_, this_.ShippedAt as ShippedAt1_1_, this_.ContactId as ContactId1_1_, customer2_.ContactId as ContactId0_0_, customer2_.LastName as LastName0_0_, customer2_.Initials as Initials0_0_, customer2_.Address as Address0_0_, customer2_.City as City0_0_, customer2_.Country as Country0_0_ FROM [Order] this_ inner join Contact customer2_ on this_.ContactId=customer2_.ContactId`

我在表名称Order（这样：[Order]）中添加了括号，它是固定的。

但是如何在NHibernate中修复此问题呢？ 是否有映射XML文件指令才能完成此操作？

（使用VS2008 SP1，SQL Server 2008 SP1，NHibernate 2.0.1 GA）

Answer 1

我想如果你在映射文件中放置引号（“[”和“]”在SQL Server中，或者你的数据库支持的任何引号），hibernate会在生成查询时引用对象名称。

（也许发布您的映射文件，所以我们可以看看）

Answer 2

请参见本节“5.3。SQL引号的标识符”。 你基本上需要这个：

<class name="Order" table="`Order`">

Answer 3

在Fluent NHibernate中，添加

.Column("`Order`");

到您的映射来修复此错误。

Answer 4

使用约定时，可以添加以下内容：

public class TableNameConvention
    : IClassConvention, IClassConventionAcceptance
{
    public void Accept(IAcceptanceCriteria<IClassInspector> criteria)
    {
        criteria.Expect(x => Check(x));
    }

    private bool Check(IClassInspector x)
    {
        return String.IsNullOrWhiteSpace(x.TableName) || x.TableName.Equals("`{0}`".Args(x.EntityType.Name));
    }

    public void Apply(IClassInstance instance)
    {
        instance.Table("`" + instance.EntityType.Name + "`");
    }
}

要解决保留表名称和保留列名称（例如'From'）的问题，可以使用以下命令：

public class ColumnNameConvention : IPropertyConvention, IPropertyConventionAcceptance
{
    public void Apply(IPropertyInstance instance)
    {
        instance.Column("`" + instance.Property.Name + "`");
    }

    public void Accept(IAcceptanceCriteria<IPropertyInspector> criteria)
    {
        criteria.Expect(c => Check(c));
    }

    private bool Check(IPropertyInspector inspector)
    {
        //walkaround:
        //this convention causes problems with Components - creates columns like Issue`Id` so we apply it only to entities

        var type = inspector.EntityType;
        if (!(type.IsSubclassOf(typeof (Entity)) || type.IsSubclassOf(typeof (GlossaryEntity))))
        {
            return false;
        }

        return true;
    }
}