1. tool
   1. sqlmetal
2. DataContext
   1. CreateDatabase
   2. DatabaseExists
   3. DeleteDatabase
   4. BeginTransaction
   5. ObjectTrackingEnabled
   6. ager load
   7. Lazy load (DeferredLoadingEnabled = false)
   8. ExecuteCommand
   9. ExecuteQuery
   10. Precompiled query
3. mapping
   1. use dbml
   2. use class attribute
      1. database name
      2. table
      3. Column
         1. AutoSync
         2. CanBeNull
         3. DbType
         4. Expression
         5. IsDiscriminator
         6. IsPrimaryKey
         7. IsDbGenerated
         8. IsVersion
         9. Name
         10. Storage
         11. TypeId
         12. UpdateCheck
      4. Association
         1. EntitySet<Order>
         2. EntityRef<Customer>
      5. InheritanceMapping
         1. Code (subclass)
         2. IsDefault
         3. Type