Data type classes

There are two data type classes in Kùzu, LogicalType and PhysicalType.

LogicalType

Logical type refers to how data is conceptually organized. This type doesn’t handle how data is actually stored. Different logical types may have the same physical type during storage/query processing, e.g. both INT32 and DATE logical type will have INT32 physical type.

During query compilation i.e. parsing, binding and planning, the logical type should always be used.

PhysicalType

Physical type refers to the specific data format as it is physically stored on disk and in memory.

Physical type is useful in storage and query processing, for e.g., columns are constructed based on physical types. Comparison operators can only work on physical types. Using the physical type is not mandatory — if you need to make a distinction between logical types, then you will need to fall back to using a logical type.