The maximum length of VARCHAR2 type in Oracle is_ Oracle modify field length SQL

Hello everyone , I'm wang Jun , An architect who can write code and recite poetry . Let's talk about it today oracle in varchar2 The maximum length of the type is _oracle Modify field length sql, I hope it can help you make progress !!!

When designing tables , Designed a field that may be used in the future ,varchar2 type , Longer length . Because it won't be used at present , Therefore, I wonder whether this design will temporarily use additional space . according to VARCHAR2 The definition of , Variable length

A string of degrees , Therefore, it should not take up extra space , After looking for some information , This conclusion is verified . But will it affect the efficiency of insertion or query , I have not studied the underlying principle of database , But based on basic logical judgment

And trust in the database , Patting the head has little effect on judgment .

therefore , stay 80% Fields that will be used later , You can pre create , otherwise , It's better to wait until it needs to be built , To avoid misunderstanding .

That's the end of today's article , Thank you for reading ,Java Architects must see I wish you a promotion and a raise , Good luck every year .