There's a further problem with databases: all database records are of a single, predefinedtype, and all instances of a record type are grouped together.
数据库还存在更多的问题，所有数据库记录有单一的预定义的类型，一种记录类型的所有实例被组织在一起。
2
It depends on predefined symbol and type definitions and is not easily modified or extended.
它依赖于预定义的符号和类型定义，并且不容易进行修改或扩展。
3
When the document of a particular type is uploaded, all these predefined parameters come into effect.