Question

是否可以在SubSonic查询中应用WHERE子句？

例如，我得到一个基于id ...

的单曲

db.Single<Storage>(id);

但是如何基于简单的WHERE子句获得单个？

db.Single<Storage>(WHERE columnname == "value");

Answer 1

这是可能的：

// Will return a Storage instance with property IsNew = true, if record does not exist
// since an object created with new never can be null
var storage1 = new Storage(1); // id = 1
var storage1 = new Storage(Storag.Columns.ColumnName, "value");

// Will return 0 if record not found (subsonic3 only)
var storage3 = (from s in Storage
               where s.ColumnName == "value"
               select s).SingleOrDefault();

// Will throw an exception if record not found  (subsonic3 only)
var storage3 = (from s in Storage
               where s.ColumnName == "value"
               select s).Single();

由于db是一个部分类，你可以扩展它。只需在同一命名空间内创建一个新文件（但解决方案中的另一个文件夹）。这适用于亚音速2，但我认为它类似于亚音速3。

public static partial class DB
{
    public static T Single<T>(String columName, Object columnValue) where T: RecordBase<T>, new()
    {
        return Select().From<T>()
                       .Where(columnName).IsEqualTo(columnValue)
                       .ExecuteSingle<T>();
    }
}

Answer 2

感谢上述情况，这是一个帮助，最终我将其简化为以下内容......

        db.Single<Storage>(s => s.ColumnName == "value");

Subsonic Single WHERE子句

2 个答案: