我正在开发一个数据库模式来处理数据收集，然后报告这些数据。
在需求讨论之后，似乎实体 - 属性 - 值（EAV）解决方案或平面表解决方案都没有问题 - 因为数据有点稀疏但不是高度稀疏。
但是，用户定义的字段将来会成为必须的，但我知道使用EAV表查询和优化RDBMS会变得复杂。
我已经看过讨论here了，我认为可以选择类似选项1 的选项。例如，有许多设置字段，然后是一些备用字段，用户可以定义标签。
在报告方面，使用这种方法而不是使用EAV是否有任何不足之处？
答案 0 :(得分：4)
你会后悔EAV，特别是在报道
时在尝试任何操作之前，请确保您了解现有的数据模型模式：Ready to use database model patterns
考虑允许用户修改自己的架构：https://martinfowler.com/bliki/UserDefinedField.html
EAV几乎总是一个非常糟糕的主意。如果在尝试上述操作后仍需要自定义字段，请使用带索引的blob类型（如JSON或XML）：http://backchannel.org/blog/friendfeed-schemaless-mysql。 Postgres的二进制Traceback (most recent call last):
File "/home/anton/Projects/pr/core/run/stuff.py", line 26, in <module>
main()
File "/home/anton/Projects/pr/core/run/stuff.py", line 23, in main
SomeObj().call()
File "/home/anton/Projects/pr/core/run/stuff.py", line 18, in call
return Session.query(SomeModel).filter(SomeModel.id == self.some_method()).all()
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 2613, in all
return list(self)
File "/home/anton/Projects/pr/core/model/cachingquery.py", line 74, in __iter__
return Query.__iter__(self)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 2761, in __iter__
return self._execute_and_instances(context)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 2776, in _execute_and_instances
result = conn.execute(querycontext.statement, self._params)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 914, in execute
return meth(self, multiparams, params)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 323, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1010, in _execute_clauseelement
compiled_sql, distilled_params
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1146, in _execute_context
context)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1341, in _handle_dbapi_exception
exc_info
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/util/compat.py", line 202, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=cause)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1139, in _execute_context
context)
File "/home/anton/Projects/pr/.venv/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 450, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) can't adapt type 'MagicMock' [SQL: 'SELECT "table".id AS table_id \nFROM "table" \nWHERE "table".id = %(id_1)s'] [parameters: {'id_1': <MagicMock name='some_method()' id='140314377476560'>}]
速度很快，允许索引/查询