如何做一个不区分大小写的first_or_create？

Question

根据datamapper文档，正确的方法是

MERGE INTO 
      Photo p
USING 
      TmpPhoto tp  ON p.ProductNumberID = tp.ProductNumberID 
                   AND p.SHA1 = tp.SHA1
WHEN 
    MATCHED AND p.Rank = tp.Rank 
THEN
    UPDATE 
        SET    p.VerifiedDate = GETDATE(),
               p.Rank = CASE 
                            WHEN p.Rank != tp.Rank AND tp.Rank != 1 THEN tp.Rank
                            WHEN p.Rank != tp.Rank AND tp.Rank  = 1 THEN tp.Rank
                            ELSE p.Rank END,
               p.Active = CASE 
                            WHEN p.Rank != tp.Rank AND tp.Rank != 1 THEN 0
                            WHEN p.Rank != tp.Rank AND tp.Rank  = 1 THEN 1
                            ELSE p.Active END
WHEN 
    NOT MATCHED
THEN
    INSERT (ProductNumberID, Code, Extension, Rank, CreatedDate, VerifiedDate, FCTH, SHA1, Active)
    VALUES (tp.ProductNumberID, tp.Code, tp.Extension, tp.Rank, getdate(), getdate(), tp.FCTH, tp.SHA1, 0)
    OUTPUT inserted.NumberID as PhotoNumberID, inserted.ProductNumberID, inserted.SHA1, inserted.Rank INTO InsertedPhotos;

假设thing = Thing.first_or_create({ conditions: ['lower(value) = ?', some_value.downcase] }, { value: some_value.downcase }) 正确返回第一条记录，Thing.first(conditions: ['lower(value) = ?', some_value.downcase])如果查询与初始值不同，则接受两个参数。

然而，上面抛出

first_or_create

我目前使用的代码只是单独执行The attribute 'conditions' is not accessible in Thing 和first。

create

但考虑到thing = Thing.first(conditions: ['lower(value) = ?', some_value.downcase]) thing = Thing.create(value: some_value.downcase) if email.nil? 的存在，我认为必须有更正确的方法。