Primary Key

Primary Key#

MuduDB requires every table to have a primary key. The primary key can be:

Inline — declared directly on a single column:
```
id INT PRIMARY KEY
```
Table-level — declared after all columns for composite keys:
```
PRIMARY KEY (col_a, col_b)
```

The primary key determines row uniqueness and, for partitioned tables, is part of the partitioning key. A column marked PRIMARY KEY is implicitly NOT NULL.