我正在使用 friendly_id 4.0.0 rails 3.0.1 和 tiny_tds 0.2.3（因为我有一个 sql server 数据库作为 rails 应用程序的后端）
在我的模型中，我有
extend FriendlyId
friendly_id :friendly_name, :use => [:slugged]
当我尝试从 rails 控制台为类创建新记录时，出现以下错误：
ActiveRecord::StatementInvalid: TinyTds::Error: 'LENGTH' is not a recognized built-in function name.: SELECT TOP (1) [j_service_provider].* FROM [j_service_provider] WHERE ([slug] = N'' OR [slug] LIKE N'--%') ORDER BY LENGTH([slug]) DESC, [slug] DESC
这是因为 SQL Server 没有 LENGTH 函数，但有一个 LEN 函数。
因此，如果我将冲突方法中 slug_generator.rb 中第 48 行的查询更改为：
scope = scope.order("LEN(#{column}) DESC, #{column} DESC")
创作作品。
find_each(&:save)但是，如果我运行它仍然无法为数据库中的现有记录生成 slugs 。
是否需要进行一些其他配置更改才能使用 tiny_tds 使friendly_id 与 sql server 一起工作？
这是堆栈跟踪：
ActiveRecord::StatementInvalid: TinyTds::Error: 'LENGTH' is not a recognized built-in function name.: SELECT TOP (1) [company].* FROM [company] WHERE ([slug] = N'' OR [slug] LIKE N'--%') ORDER BY LENGTH([slug]) DESC, [slug] DESC
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:202:in `log'
from /usr/lib/ruby/gems/1.8/gems/activerecord-sqlserver-adapter-3.0.7/lib/active_record/connection_adapters/sqlserver/database_statements.rb:249:in `raw_select'
from /usr/lib/ruby/gems/1.8/gems/activerecord-sqlserver-adapter-3.0.7/lib/active_record/connection_adapters/sqlserver/database_statements.rb:193:in `select'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/query_cache.rb:56:in `select_all'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/base.rb:467:in `find_by_sql'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/relation.rb:64:in `to_a'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/relation/finder_methods.rb:333:in `find_first'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/relation/finder_methods.rb:122:in `first'
from /usr/lib/ruby/gems/1.8/gems/friendly_id-4.0.0/lib/friendly_id/slug_generator.rb:38:in `conflict'
from /usr/lib/ruby/gems/1.8/gems/friendly_id-4.0.0/lib/friendly_id/slug_generator.rb:33:in `conflict?'
from /usr/lib/ruby/gems/1.8/gems/friendly_id-4.0.0/lib/friendly_id/slug_generator.rb:23:in `generate'
from /usr/lib/ruby/gems/1.8/gems/friendly_id-4.0.0/lib/friendly_id/slugged.rb:257:in `set_slug'
from /usr/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/callbacks.rb:424:in `_run_validation_callbacks'
from /usr/lib/ruby/gems/1.8/gems/activemodel-3.0.1/lib/active_model/validations/callbacks.rb:67:in `run_validations!'
from /usr/lib/ruby/gems/1.8/gems/activemodel-3.0.1/lib/active_model/validations.rb:179:in `valid?'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/validations.rb:55:in `valid?'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/validations.rb:75:in `perform_validations'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/validations.rb:43:in `save'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/attribute_methods/dirty.rb:21:in `save'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:237:in `save'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:289:in `with_transaction_returning_status'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:204:in `transaction'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:287:in `with_transaction_returning_status'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:237:in `save'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:248:in `rollback_active_record_state!'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/transactions.rb:236:in `save'
from /usr/lib/ruby/gems/1.8/gems/activerecord-3.0.1/lib/active_record/base.rb:498:in `create'