What's the requirement for a database schema (baked into the DB) basically can configure my MySQL DB structure and write CRUD claims to utilize it directly? I have never labored with one of these, but I am presuming they are just for performance optimisation?

I understand of schema diagrams that may be released as .sql instructions which create the DB structure, for instance with MySQL Workbench.

Your real question is not totally obvious in my experience. If you're asking about why come with an editable graphical representation from the schema, then there's no need for any graphical representation from the structure of the database.

It certainly is available in handy if you need to learn instantly the way a database is organized or communicate with other people your DB design. And it is sometimes simpler to edit the graphical representation rather than using DDL sentences.

If you wish to know whereby the DB may be the schema saved, it's uncovered with the standard INFORMATION_SCHEMA tables. Obviously the DDL is incorporated in the database (else wouldso would the db understand how to keep data)

Well, you can create every column inside your database as VARCHAR(255), however the result is going to be incredibly slow.

Consider how a database does the querying: we have an index (think about a catalog inside a dictionary). It appears with the index and finds the best record (the best page within the dictionary). Then, it returns the record.

When the index is small, the research is fast - because more "pages" from the index can squeeze into memory at the same time (just consider it - is not it simpler to appear with the dictionary index whether it's 2 pages rather than 500?). So utilizing an integer index for querying is significantly faster than utilizing a string index.