BigQuery的。 “在末尾添加NULLABLE或REPEATED列”是什么意思?

时间:2022-11-30 15:30:59

I want to update table in Bigquery. Here is a documentation that says what can and can not be done: https://cloud.google.com/bigquery/docs/tables#updateschema It says:

我想在Bigquery中更新表。这是一份文档,说明可以做什么和不可以做什么:https://cloud.google.com/bigquery/docs/tables#updateschema它说:

Allowed operations include:

允许的操作包括:

Adding NULLABLE or REPEATED columns at the end
Making REQUIRED fields NULLABLE

I was able to update table by inserting NULLABLE and REPEATED fields, nested in my schema.

我能够通过插入嵌套在我的模式中的NULLABLE和REPEATED字段来更新表。

I don't understand what does "at the end" part mean. Isn't it an internal detail about how Bigquery stores data?

我不明白“最后”部分是什么意思。这不是关于Bigquery如何存储数据的内部细节吗?

2 个解决方案

#1


I guess documentation talks about logical order that you see when browsing table or doing "select *". The physical storage is implementation detail, but logical order is visible.

我猜文档会讨论在浏览表格或执行“select *”时看到的逻辑顺序。物理存储是实现细节,但逻辑顺序是可见的。

#2


You can add columns only to the end of the structure only. You cannot reorder columns or add a column in the middle, like 2nd column.

您只能将列添加到结构的末尾。您无法重新排序列或在中间添加列,如第2列。

#1


I guess documentation talks about logical order that you see when browsing table or doing "select *". The physical storage is implementation detail, but logical order is visible.

我猜文档会讨论在浏览表格或执行“select *”时看到的逻辑顺序。物理存储是实现细节,但逻辑顺序是可见的。

#2


You can add columns only to the end of the structure only. You cannot reorder columns or add a column in the middle, like 2nd column.

您只能将列添加到结构的末尾。您无法重新排序列或在中间添加列,如第2列。