DML - IUDS, CR
insert, update, delete, select
commit, rollback
INSERT - add new rows
UPDATE - modify data of existing rows
DELETE - delete some/all records from database
can be rolled back
COMMIT - permanently saves
ROLLBACK - undo changes
SELECT - data retrieval
WHERE - limits rows retur...
IN - ✔✔checks value if it matches given value list
EXISTS - ✔✔checks if subquery returns any rows
COUNT - ✔✔tally amount of NON-NULL values
SUM - ✔✔total sum for specified attribute
HAVING - ✔✔filters the groups subject to some condition
used after group by
inner join - ✔✔only rows that meet criteria selected
outer join - ✔✔matching rows and unmatched values for one/both tables
natural join - ✔✔returns ALL rows with matching values
deletes duplicate columns
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller eustacemaina122. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.49. You're not tied to anything after your purchase.