数据库设计可动态创建表 [英] Database design to create tables on the fly

问题描述

我需要在数据库中动态创建动态表.例如，在数据库中，我将有名为:

I need to create dynamic tables in the database on the fly. For example, in the database I will have tables named:

Table
Column
DataType
TextData
NumberData
DateTimedata
BitData

在这里，我可以在名为table的表中添加一个表，然后可以将所有列添加到columns表中的该表，并将数据类型与每个列相关联.

Here I can add a table in the table named table, then I can add all the columns to that table in the columns table and associate a datatype to each column.

基本上，我想创建表而不在数据库中实际创建表.这有可能吗?如果是这样，您可以将我定向到正确的位置以便我进行研究吗?另外，我更喜欢sql server或任何免费的数据库软件.

Basically I want to create tables without actually creating a table in the database. Is this even possible? If so, can you direct me to the right place so I can research? Also, I would prefer sql server or any free database software.

谢谢

推荐答案

您所描述的是

What you are describing is an entity-attribute-value model (EAV). It is a very poor way to design a data model.

尽管数据模型非常灵活，但是查询这样的数据模型却非常复杂.如果要选择或过滤n个不同的属性，您经常不得不不得不自联接表n次.这变得越来越慢，并且变得相对难以快速优化.

Although the data model is quite flexible, querying such a data model is quite complicated. You frequently end up having to self-join a table n times if you want to select or filter on n different attributes. That gets slow rather slow and becomes rather hard to optimize relatively quickly.

此外，您通常最终会构建数据库或ORM将提供的许多功能.

Plus, you generally end up building a lot of functionality that the database or your ORM would provide.

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