The following table maps DuckDB types to Apache Arrow and Apache Iceberg types:
| DuckDB | Description | Arrow | Iceberg |
|---|---|---|---|
BIGINT |
Signed eight-byte integer | int64 |
long |
BOOLEAN |
Logical boolean (true | false) | bool |
boolean |
BLOB |
Variable-length binary data | binary |
binary |
DATE |
Calendar date (year, month day) | date32 |
date |
DOUBLE |
Double precision floating-point number (8 bytes) | float64 |
double |
DECIMAL |
Fixed-precision floating point number | decimal128 |
decimal |
HUGEINT |
Signed sixteen-byte integer | Cast to int64 (with loss) |
Cast to long (with loss) |
INTEGER |
Signed four-byte integer | int32 |
int |
INTERVAL |
Date | time delta | month_day_nano_interval |
Cast to long |
LIST |
List with elements of any data type | list_ |
list |
MAP |
Map with keys and values of any data type | map_ |
map |
REAL |
Single precision floating-point number (4 bytes) | float32 |
float |
SMALLINT |
Signed two-byte integer | int16 |
Cast to int |
STRUCT |
Record with named fields of any data type | struct |
struct |
TIME |
Time of day (no time zone) | time32 |
time |
TIMESTAMP |
Combination of time and date | timestamp |
timestamp |
TIMESTAMPTZ |
Combination of time and date with time zone | timestamp |
timestamptz |
TINYINT |
Signed one-byte integer | int8 |
Cast to int |
UBIGINT |
Unsigned eight-byte integer | uint64 |
Cast to long |
UINTEGER |
Unsigned four-byte integer | uint32 |
Cast to int |
USMALLINT |
Unsigned two-byte integer | uint16 |
Cast to int |
UTINYINT |
Unsigned one-byte integer | uint8 |
Cast to int |
UUID |
UUID data type | Cast to string |
Cast to fixed |
VARCHAR |
Variable-length character string | string |
string |
Cast to INTERVAL |
Duration in nanoseconds | duration |
Cast to long |
Cast to VARCHAR |
Fixed-length character string | Cast to string |
fixed |
Note: A FIXED type for fixed-length character strings might be added to DuckDB.
Note: The dictionary, field, and schema Apache Arrow types are ignored for now.