mysql--PRIMARY Key auto-Grow & unique Index

Let's start by talking about the primary key and the unique index: a table of one database has only one primary key , and a primary key cannot repeat a unique index: a single table on a database can have multiple , just the value on the unique index cannot be duplicated , as is the primary key

Below we create a unique index with a primary key, and the primary key is autogrow

CREATE TABLE demo (ID int primary key auto_increment, name Char (TEN) unique key, age int);

Next we insert the data to see

mysql--PRIMARY Key auto-Grow & unique Index