可以凝结主键/序列？ [英] Possible to condense primary key/serial?

问题描述

我有一个数据库，一切都与外键链接，所以Postgres完全知道数据库是如何布局的。

好吧，让我们说我有Table1和Table2。

Table1有3个字段。 RID，table2_rid，data
$ b $所以table1.table2_rid引用table2.RID，这是用一个外键表示的。在 RID 字段中都是主键，并且是一个序列类型。

我想知道的是如何凝结主键？比如说你添加了5条记录，删除了3条记录。你的主键看起来就像

  1 
 2 
 
 
 $ / code> 

那么，我怎样才能到处更新，键（和相应的外键）可以被压缩成


  1 
 2 
 3 
 4 
  




解决方案

最好不要改变主键：重新编号他们是一个PITA。

如果您需要一个人类的ID，一个没有空白的ID，Elein Mustain显示如何创建无间隙序列。

I have a database where everything is linked with foreign keys, so the Postgres knows exactly how the database is layed out..

Well, Lets say I have Table1 and Table2.

Table1 has 3 fields. RID, table2_rid,data

So table1.table2_rid references table2.RID and this is expressed with a foreign key. In both the RID field is the primary key and is a serial type.

What I would like to know is how to "condense" the primary keys? Like say you add 5 records and deleted record number 3. Your primary keys would look like

1
2
4
5 

Well, how do I get to update everywhere so that the primary key(and corresponding foreign keys) can be condensed into

1
2
3
4

解决方案

It's best if a primary key never changes: Renumbering them is a PITA.

If you need an ID for humans, one that has no gaps, A. Elein Mustain shows how to create a gapless sequence.

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