Clustered Indexes

00:00

I welcome back to module five. This is less than 5.2 clustered indexes. There's not gonna be an implementation on this lesson. We're just gonna describe what the difference is between the Clustered Index and a regular secondary index.

00:15

So my sequel requires a cluster to index on every table.

00:20

My sequel automatically used the primary key as a clustered index. Now, something to keep in mind is this. Convey Ari from database engine to database engine. Microsoft sequel does not require a clustered index on every table, and the impact of the index

00:37

can vary from engine to engine as well.

00:40

But in general, indexes are just simply used to speed up the debt. Operations on the table,

00:47

so clustered indicates that the index architecture is saved on disc in a specific order in a specific pattern that optimizes searching,

00:58

you can only have one clustered index.

01:00

A non clustered index is not saved on disk and uses memory pointers.

01:06

You can have many non closer to indexes, and we saw that when we added indexes to our tables and we added three columns of indexes on some of them.

01:17

Index is slow down, right operations the database may need to rearrange the records to maintain the index. So when you insert a new record or you edit an old record

01:27

and you edit the index column, the database engine may need to rearrange the records in order to maintain the index in the correct order so this can have an impact on your right performance.

01:42

Generally, the actual architecture er off the index may be treated as an abstraction.

01:48

And what this means is you do not need to know every detail, off the index architecture and how it operates. You just need to know the appropriate. You use cases when it's appropriate to use an index when it's appropriate. Not whether or not it's better to have it as a clustered index or secondary index, those kind of things.

02:07

So let's go ahead and take a look at the summary for this lesson

02:13

and to summarize my sequel requires every table has a clustered index.

02:19

The primary key is used by default.

02:22

All other indexes are considered secondary indexes,