Question

我们正在使用fluentnhibernate和自动化，我们有一个命名约定，所有列都是外键，列名将以“Key”结尾。所以我们有一个看起来像这样的约定：

public class ForeignKeyColumnNameConvention : IReferenceConvention
{
    public void Apply ( IManyToOneInstance instance )
    {
        // name the key field
        string propertyName = instance.Property.Name;

        instance.Column ( propertyName + "Key" );
    }
}

这很有效，直到我们创建了一个组件，其中一个值是外键。通过在此重命名列，它将覆盖为组件列指定的默认名称，该列包含在AutomappingConfiguration中定义的ComponentPrefix。有没有办法让我在这个约定中获得ComponentPrefix？或者是否有其他方法让我获取具有属性的组件的列名称，该属性是以“Key”结尾的外键？

Answer 1

经过大量的摆弄和试用后错误（因此很想用反射来使用你的解决方案）我想出了以下内容：

此方法取决于约定的执行顺序。这种约定顺序通过严格的层次结构发生。在此示例中，首先，正在处理组件（IDynamicComponentConvention）的约定，然后处理内部属性的约定，例如引用映射（IReferenceConvention）。

严格的命令是我们进行罢工的地方：

我们在调用Apply(IDynamicComponentConvention instance)时汇集了列的正确名称，并将其放入队列中。 请注意，使用Queue<T>这是一个FIFO（先进先出）集合类型，因此它可以正确保存订单。
在此之后几乎立即调用Apply(IManyToOneInstanceinstance)。我们检查队列中是否有任何内容。如果有，我们将其从队列中取出并将其设置为列名。 请注意，您不应使用Peek()而不是Dequeue()，因为它不会从队列中删除对象。

代码如下：

public sealed class CustomNamingConvention : IDynamicComponentConvention, IReferenceConvention {
    private static Queue<string> ColumnNames = new Queue<string>();

    public void Apply(IDynamicComponentInstance instance) {
        foreach (var referenceInspector in instance.References) {
            // All the information we need is right here
            // But only to inspect, no editing yet :(
            // Don't worry, just assemble the name and enqueue it
            var name = string.Format("{0}_{1}",
                instance.Name,
                referenceInspector.Columns.Single().Name);
            ColumnNames.Enqueue(name);
        }
    }

    public void Apply(IManyToOneInstance instance) {
        if (!ColumnNames.Any())
            // Nothing in the queue? Just return then (^_^)
            return;

        // Set the retrieved string as the column name
        var columnName = ColumnNames.Dequeue();
        instance.Column(columnName);

        // Pick a beer and celebrate the correct naming!
    }
}

Answer 2

我已经找到了一种方法，使用反射来获取IComponentInstance公开的IManyToOneInspector的底层映射，但是希望有更好的方法来做到这一点？

以下是我如何实现这一目标的示例代码：

#region IConvention<IComponentInspector, IComponentInstance> Members 
    public void Apply(IComponentInstance instance) 
    { 
        foreach (var manyToOneInspector in instance.References) 
        { 
            var referenceName = string.Format("{0}_{1}_{2}{3}", instance.EntityType.Name, manyToOneInspector.Property.PropertyType.Name, _autoMappingConfiguration.GetComponentColumnPrefix(instance.Property), manyToOneInspector.Property.Name); 
            if(manyToOneInspector.Property.PropertyType.IsSubclassOf(typeof(LookupBase))) 
            { 
                referenceName += "Lkp"; 
            } 
            manyToOneInspector.Index ( string.Format ( "{0}_FK_IDX", referenceName ) ); 
        } 
    } 
#endregion 
public static class ManyToOneInspectorExtensions 
{ 
    public static ManyToOneMapping GetMapping(this IManyToOneInspector manyToOneInspector) 
    { 
        var fieldInfo = manyToOneInspector.GetType ().GetField( "mapping", BindingFlags.NonPublic | BindingFlags.Instance ); 
        if (fieldInfo != null) 
        { 
            var manyToOneMapping = fieldInfo.GetValue( manyToOneInspector ) as ManyToOneMapping; 
            return manyToOneMapping; 
        } 
        return null; 
    } 
    public static void Index(this IManyToOneInspector manyToOneInspector, string indexName) 
    { 
        var mapping = manyToOneInspector.GetMapping (); 
        mapping.Index ( indexName ); 
    } 
    public static void Column(this IManyToOneInspector manyToOneInspector, string columnName) 
    { 
        var mapping = manyToOneInspector.GetMapping (); 
        mapping.Column ( columnName ); 
    } 
    public static void ForeignKey(this IManyToOneInspector manyToOneInspector, string foreignKeyName) 
    { 
        var mapping = manyToOneInspector.GetMapping(); 
        mapping.ForeignKey ( foreignKeyName ); 
    } 
} 
public static class ManyToOneMappingExtensions 
{ 
    public static void Index (this ManyToOneMapping manyToOneMapping, string indexName) 
    { 
        if (manyToOneMapping.Columns.First().IsSpecified("Index")) 
            return; 
        foreach (var column in manyToOneMapping.Columns) 
        { 
            column.Index = indexName; 
        } 
    } 
    public static void Column(this ManyToOneMapping manyToOneMapping, string columnName) 
    { 
        if (manyToOneMapping.Columns.UserDefined.Count() > 0) 
            return; 
        var originalColumn = manyToOneMapping.Columns.FirstOrDefault(); 
        var column = originalColumn == null ? new ColumnMapping() : originalColumn.Clone(); 
        column.Name = columnName; 
        manyToOneMapping.ClearColumns(); 
        manyToOneMapping.AddColumn(column); 
    } 
    public static void ForeignKey(this ManyToOneMapping manyToOneMapping, string foreignKeyName) 
    { 
        if (!manyToOneMapping.IsSpecified("ForeignKey")) 
            manyToOneMapping.ForeignKey = foreignKeyName; 
    } 
}

如何重命名作为外键的组件列？

2 个答案: