How to set two primary keys in a table in a database

In fact, the practice is simple.

The uniqueness of the database in the rules is one of the most primary keys in a single table.

If you want to set two primary keys, then only in the Union table or two fields together,

For example

Table student (Sno, sname, age)

Table Course (CNO, sname, Grade)

The primary key is unique, and a table has a maximum of one primary key,

However, you can combine 2 fields to set a primary key.

1. Select Table-

2. Design Table-

3. Check fields (multiple hold CTR)

4. Right-click to set the primary key.

5, Oh, and then to refresh a bit. If the previously entered data will be an error ( very normal ), it is because the primary key has changed. Just need to re-enter the data. 

How to set two primary keys in a table in a database