[英]What's a good database design for hierarchical data versioning with Hibernate?
I need to store a history of changes for hierarchical data. 我需要存储分层数据的更改历史记录。 The data is a one-to-many relation: a setting entity has many properties. 数据是一对多关系:设置实体具有许多属性。 Here are my tables: 这是我的桌子:
Setting
------------------------------
Id INTEGER NOT NULL
CompanyId INTEGER NOT NULL
Name TEXT NOT NULL
SettingProperty
------------------------------
SettingId INTEGER NOT NULL
PropertyName TEXT NOT NULL
I'm using Hibernate as the ORM, the corresponding Java entity would look somewhat like this 我使用Hibernate作为ORM,相应的Java实体看起来像这样
public class Setting {
private int id;
private int companyId;
private String name;
private Set<String> properties;
// ....
}
Now, whenever the setting name changes or a property is added to the setting, I need to store the full history of changes. 现在,每当设置名称更改或将属性添加到设置时,我都需要存储更改的完整历史记录。 I also need to easily query the historical setting for a given point in time. 我还需要轻松查询给定时间点的历史设置。 I've taken into account multiple different options, ie: 我考虑了多个不同的选项,即:
Any suggestions or better ideas? 有什么建议或更好的主意吗? Please keep in mind that I'm using Hibernate so not all SQL query quirks are possible. 请记住,我正在使用Hibernate,因此并非所有SQL查询怪癖都是可行的。 My DB is PostgreSQL. 我的数据库是PostgreSQL。
Eventually we decided to use Hibernate Envers because it does al the work for us 最终我们决定使用Hibernate Envers,因为它确实为我们完成了工作
So we'll use whatever mapping tables it generates for us :) 因此,我们将使用它为我们生成的任何映射表:)
I don't have experience with history tables, but this might help: 我没有使用历史记录表的经验,但这可能会有所帮助:
First, I would suggest having your friendly neighborhood DBA review your database schema. 首先,我建议让您的友好邻居DBA审查您的数据库架构。 Although I'm not a DBA, here are a few suggestions: 尽管我不是DBA,但这里有一些建议:
Setting
settingID long not null, primary key
companyID long not null, foreign key to Company table
name varchar(255) not null, unique
SettingProperty
settingPropertyID long not null, primary key
settingID long not null, foreign key to Setting table
name varchar(255) not null, unique
Company
companyID long not null, primary key
name varchar(255) not null, unique
abbr varchar(50), unique
Notes:
0: primary keys are always named with the table name followed by 'ID'.
1: Table names begin with a capital letter
2: column names begin with a lower case letter
3: primary keys are to have no business meaning
4: primary and foreign keys are long and not int
to ensure the max value isn't likely to be reached.
5: I suggest you consider calling your tables something
more meaningful than Setting and SettingProperty (assuming
there is such a meaning).
6: Consider adding company abbreviation to your Company
table (abbr), which can be null, but must be unique.
7:Don't add columns to the database tables being audited
with auditing information. They should be ignorant of the fact
they are being audited.
8: Use database triggers to update a history table when a record
is updated, inserted, or deleted. Don't do it in Java.
9: Search Google for 'store historical data in database triggers' or similar search
on how to best create a history table.
Example:
https://www.google.com/#q=storing+historical+data+in+database+triggers&start=10
10: There is a column with not null and unique, and another with nullable and unique.
Some databases don't like nullable and unique (it treats more than one null in the
column as violating the unique rule).
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