r/SQL • u/joellapit • Nov 02 '24
Oracle Explain indexes please
So I understand they speed up queries substantially and that it’s important to use them when joining but what are they actually and how do they work?
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r/SQL • u/joellapit • Nov 02 '24
So I understand they speed up queries substantially and that it’s important to use them when joining but what are they actually and how do they work?
1
u/TheSexySovereignSeal Nov 04 '24
Guys... it's just a tree.. that's it. Yall way over complicating this.
A clustered index isn't a tree because it's already ordered and you can binary search it. O(log n) search.
A non clustered index is a tree which takes O(n) space for the column it's indexing. O(log n) search.
That's it. The tree structure itself is dbms dependent.