Binary Data Types¶
Table 1 lists the binary data types that can be used in GaussDB(DWS).
Name | Description | Storage Space |
|---|---|---|
BLOB | Binary large object. Currently, BLOB only supports the following external access interfaces:
For details about these interfaces, see "Stored Procedures" > "Advanced Packages" > "DBMS_LOB" in the Data Warehouse Service (DWS) Developer Guide. Note Column storage cannot be used for the BLOB type. | The maximum size is 10,7373,3621 bytes (1 GB - 8203 bytes). |
RAW | Variable-length hexadecimal string Note Column storage cannot be used for the raw type. | 4 bytes plus the actual hexadecimal string. The maximum size is 10,7373,3621 bytes (1 GB - 8203 bytes). |
BYTEA | Variable-length binary string | 4 bytes plus the actual binary string. The maximum size is 10,7373,3621 bytes (1 GB - 8203 bytes). |
Note
In addition to the size limitation on each column, the total size of each tuple is 8203 bytes less than 1 GB.
Examples
-- Create a table:
CREATE TABLE blob_type_t1
(
BT_COL1 INTEGER,
BT_COL2 BLOB,
BT_COL3 RAW,
BT_COL4 BYTEA
) DISTRIBUTE BY REPLICATION;
--Insert data:
INSERT INTO blob_type_t1 VALUES(10,empty_blob(),
HEXTORAW('DEADBEEF'),E'\\xDEADBEEF');
-- Query data in the table:
SELECT * FROM blob_type_t1;
bt_col1 | bt_col2 | bt_col3 | bt_col4
---------+---------+----------+------------
10 | | DEADBEEF | \xdeadbeef
(1 row)
-- Delete the tables:
DROP TABLE blob_type_t1;