如何在NHibernate Linq查询中执行不区分大小写的where?
例如
//note this one doesn't work if the entry in database has lowercase
q => q.Where(entity =>
entity.CaseInsensitiveField == DesiredField.Trim().ToUpper())
试试这个:
q => q.Where(entity => entity.CaseInsensitiveField.ToUpper() == DesiredField.Trim().ToUpper())
此外,我建议在查询之外设置参数:
var value = DesiredField.Trim().ToUpper();
...
q => q.Where(entity => entity.CaseInsensitiveField.ToUpper() == value)
使用此:
q => q.Where(entity =>
String.Equals(entity.CaseInsensitiveField , CaseInsensitiveField ,
StringComparison.OrdinalIgnoreCase));
更新
似乎(至少通过LinqPad)以上内容不会转化为SQL,所以我建议,正如ivowiblo已经建议的那样:
var comparisonValue = CaseInsensitiveField.ToUpper();
q => q.Where(entity =>
entity.CaseInsensitiveField.ToUpper() == comparisonValue);
事先设置ToUpper的原因是SQL中的过程函数通常更差,而且由于这不是数据库字段,我们可以将其发送到已经大写的字段中。