在 Rails 中使用 Active Record 时如何指定 Ruby 正则表达式?
要获得所有 invoice_number 是纯数字的工作，我要做的:
To get all jobs which invoice_number is a pure number I do:
Job.where("invoice_number REGEXP '^[[:digit:]]+$'")
是否可以通过在 Ruby 而不是 MySQL 中指定正则表达式来做同样的事情?
Is it possible to do the same by specifying the regex in Ruby rather than MySQL ?
推荐答案
一种方法是
Job.all.select{|j| j =~ /^d+$/}
但它不会像 MySQL 版本那样高效.
but it will not be as efficient as the MySQL version.
另一种可能是使用命名范围来隐藏丑陋的 SQL:
Another possibility is to use a named scope to hide the ugly SQL:
named_scope :all_digits, lambda { |regex_str|
{ :condition => [" invoice_number REGEXP '?' " , regex_str] }
}
然后你有Job.all_digits.
请注意，在第二个示例中，您正在为数据库组装查询，因此 regex_str 需要是 MySQL 正则表达式字符串，而不是 Ruby Regex 对象，后者的语法略有不同.
Note that in the second example, you are assembling a query for the database, so regex_str needs to be a MySQL regex string instead of a Ruby Regex object, which has a slightly different syntax.
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