Dynamic Columns in Mariadb (Part 1)

In this article, we will explore the concept of dynamic columns in MariaDB, including how they work, how to create and use them, and their benefits and limitations.

Dynamic Columns

Dynamic columns are a feature in MariaDB that allow the creation of columns that can store data in a flexible and scalable manner. Unlike traditional columns, which have a fixed data type and length, dynamic columns can store data structures of varying complexity, including arrays, maps, and even entire JSON documents.

Dynamic columns work by storing the data in a binary format that can be parsed and manipulated by MariaDB using a set of functions and operators. This allows developers to create and store complex data structures in a single column, without the need for multiple columns or tables.

Creation and Use of Dynamic Columns

Creating a dynamic column in MariaDB is relatively straightforward. To create a dynamic column, you need to specify the column type as DYNAMIC when creating the table. For example, the following SQL statement creates a table with a dynamic column:

CREATE TABLE my_table (
  id INT NOT NULL PRIMARY KEY,
  dynamic_column DYNAMIC
);

Once you have created a table with a dynamic column, you can insert data into the column using the INSERT statement. The data should be in the binary format expected by the dynamic column.

To retrieve data from a dynamic column, you can use the dynamic column functions and operators provided by MariaDB. These functions and operators allow you to extract and manipulate data stored in the dynamic column, and can be used in SQL queries and stored procedures.

Here is an example of how to use the dynamic column functions to extract data from a dynamic column:

SELECT id, DYNAMIC_COLUMN_GET(dynamic_column, 'key1') AS value1, DYNAMIC_COLUMN_GET(dynamic_column, 'key2') AS value2
FROM my_table;

This query retrieves the id, value1, and value2 fields from the my_table table. The DYNAMIC_COLUMN_GET function is used to extract the values associated with the key1 and key2 keys in the dynamic column.

Benefits and Limits of Dynamic columns are discussed in next part part-2