django的聚集指数

Question

I have two tables in my models:

1)Owner:

OwnerName

2)Car

OwnerKey

CarName

CarPrice

Here while creating a row in Owner table, I also add the Cars for that owner Car table. So all the cars for a particular owner are stored sequentially in the Car table.Now if I want to ask whether should I use cluster indexing or not? Once the cars for a particular owner are saved, no cars are then added for that owner neither any car is deleted, just the price is changed. What should I do for a faster access? And how to implement cluster index via django?

Answer 1

You question is asking for information that requires studying the SQL, not just the Django code.

If you have only a thousand owners and cars, things will probably be fast enough. If you have a million owners or cars, you need indexes, not necessarily "clustered".

A "clustered" key is implemented in MySQL as a PRIMARY KEY . You can have only one per table, and its values must be unique.

I Django, do something like this to get a PK:

column1 = models.IntegerField(primary_key = True)

Please provide the table schema you already have. That is, go beyond Django and get SHOW CREATE TABLE . (What you have provided is too vague; hence my answer is too vague.)

References:

• https://code.djangoproject.com/ticket/8316
• Two primary keys specified in MySQL database -- It's really talking about having a "composite" PRIMARY KEY .

There are no "clustered" indexes other than the PRIMARY KEY . However, a secondary key can have similar performance if it is a "covering index". That term refers to an index that contains all the columns that are found in the SELECT . Also , the columns are ordered correctly.

Let's see your SELECT statements in order to better judge what is needed.