# BLOB and TEXT Data Types

## Description

A `BLOB` is a binary large object that can hold a variable amount of data. The four `BLOB` types are

* [TINYBLOB](/docs/server/reference/data-types/string-data-types/tinyblob.md),
* [BLOB](/docs/server/reference/data-types/string-data-types/blob.md),
* [MEDIUMBLOB](/docs/server/reference/data-types/string-data-types/mediumblob.md), and
* [LONGBLOB](/docs/server/reference/data-types/string-data-types/longblob.md).

These differ only in the maximum length of the values they can hold.

The `TEXT` types are

* [TINYTEXT](/docs/server/reference/data-types/string-data-types/tinytext.md),
* [TEXT](/docs/server/reference/data-types/string-data-types/text.md),
* [MEDIUMTEXT](/docs/server/reference/data-types/string-data-types/mediumtext.md), and
* [LONGTEXT](/docs/server/reference/data-types/string-data-types/longtext.md).
* [JSON](/docs/server/reference/data-types/string-data-types/json.md) (alias for LONGTEXT)

These correspond to the four `BLOB` types and have the same maximum lengths and [storage requirements](/docs/server/reference/data-types/data-type-storage-requirements.md).

`BLOB` and `TEXT` columns can have a `DEFAULT` value.

{% hint style="info" %}
It is possible to set a unique index on columns that use the `BLOB` or `TEXT` data types.
{% endhint %}

## Handling Large Data via APIs

When working with very large `BLOB` or `TEXT` values, the data may exceed the limit set by the [max\_allowed\_packet](/docs/server/server-management/variables-and-modes/server-system-variables.md#max_allowed_packet) system variable. To avoid this—and to reduce memory consumption on the client—most MariaDB connectors allow you to "stream" data in chunks.

* Connector/C: Use [mysql\_stmt\_send\_long\_data()](/docs/connectors/mariadb-connector-c/api-prepared-statement-functions/mysql_stmt_send_long_data.md) to send parameter data in pieces before calling [mysql\_stmt\_execute()](/docs/connectors/mariadb-connector-c/api-prepared-statement-functions/mysql_stmt_execute.md). This bypasses `max_allowed_packet` limits and reduces the peak memory footprint (RSS) of the application.
* Connector/J: Use `PreparedStatement.setBinaryStream()` (for `BLOB`) or `PreparedStatement.setCharacterStream()` (for `TEXT`).
* Protocol: These APIs utilize the [COM\_STMT\_SEND\_LONG\_DATA](/docs/server/reference/clientserver-protocol/3-binary-protocol-prepared-statements/com_stmt_send_long_data.md) command, which appends data to a parameter on the server side.

### **Technical Rules for C/C++**

* 0-Based Indexing: Parameter numbering starts at `0`.
* The `is_null` Flag: This must be `0`; if set to nonzero, the server may discard the streamed data.
* Resetting: Use [mysql\_stmt\_reset()](/docs/connectors/mariadb-connector-c/api-prepared-statement-functions/mysql_stmt_reset.md) to clear all accumulated long data on the server if you need to abort or retry.
* Chunk Size: A practical performance "sweet spot" is between `64` KB and `1` MB per chunk.

## See Also

* [Store a column as compressed](/docs/server/server-usage/tables/create-table.md#compressed)

<sub>*This page is licensed: GPLv2, originally from*</sub> [<sub>*fill\_help\_tables.sql*</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

{% @marketo/form formId="4316" %}


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