In the Room Persistence Library, to make a primary key auto-increment, we use the annotation @PrimaryKey(autoGenerate = true). This tells Room that the field should automatically increase its value each time a new record is inserted into the database.

Example:

java

CopyEdit

@Entitypublic class Student { @PrimaryKey(autoGenerate = true) public int id; public String name; public int age; }

In the example above, the id field is the primary key, and autoGenerate = true ensures that Room will auto-increment it for each new Student entry.

Conclusion:
To make a primary key auto-increment in Room, use @PrimaryKey(autoGenerate = true).