BLOB

Syntax

BLOB[(M)]

Description

A BLOB column with a maximum length of 65,535 (216 - 1) bytes. Each BLOB value is stored using a two-byte length prefix that indicates the number of bytes in the value.

An optional length M can be given for this type. If this is done, MariaDB creates the column as the smallest BLOB type large enough to hold values M bytes long.

BLOBS can also be used to store dynamic columns.

BLOB and TEXT columns can both be assigned a DEFAULT value.

See also: Data Types for MariaDB Enterprise Server 11.4, in 10.6 ES, in 10.5 ES, in 10.4 ES, in 10.3 ES, in 10.2 ES, in 10.6 CS, in 10.5 CS, in 10.4 CS, in 10.3 CS, and in 10.2 CS.

Indexing

On a column that uses the BLOB data type, setting a unique index is now possible.

Oracle Mode

In Oracle mode, BLOB is a synonym for LONGBLOB.

EXAMPLES

BLOB

Example of BLOB:

CREATE TABLE blob_example (
   description VARCHAR(20),
   example BLOB
) DEFAULT CHARSET=latin1; -- One byte per char makes the examples clearer

INSERT INTO blob_example VALUES
   ('Normal foo', 'foo'),
   ('Trailing spaces foo', 'foo      '),
   ('NULLed', NULL),
   ('Empty', ''),
   ('Maximum', RPAD('', 65535, CHAR(7)));

SELECT description, LENGTH(example) AS length
   FROM blob_example;

+---------------------+--------+
| description         | length |
+---------------------+--------+
| Normal foo          |      3 |
| Trailing spaces foo |      9 |
| NULLed              |   NULL |
| Empty               |      0 |
| Maximum             |  65535 |
+---------------------+--------+

Data Too Long

When SQL_MODE is strict (the default) a value is considered "too long" when its length exceeds the size of the data type, and an error is generated.

Example of data too long behavior for BLOB:

TRUNCATE blob_example;

INSERT INTO blob_example VALUES
   ('Overflow', RPAD('', 65536, CHAR(7)));

ERROR 1406 (22001): Data too long for column 'example' at row 1

See Also

• BLOB and TEXT Data Types
• Data Type Storage Requirements
• Oracle mode from MariaDB 10.3