it's possible to use sequences in mariaDB Server? - sql

Question

A sequence is an alternative to create for example the Primary Key on every record in your tables.
So this is the common syntax I'm using actually
CREATE TABLE users(
id BIGINT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(100) UNIQUE NOT NULL
);
As you can see the common solution I implemented is the PRIMARY KEY clausule
But is RDBMS such as Oracle or PostgreSQL is possible to use sequences for replacing the previous code
For example in Oracle you declare
CREATE SEQUENCE id
START WITH 1
INCREMENT BY 1;
Or in PostgreSQL in this way
CREATE SEQUENCE id
START WITH 1
INCREMENT BY 1;
But this is possible in mariaDB Server?

Answer 1

In MariaDB since version 10.3 there is the possibility of natively using the creation of sequences; through the following example you can see how it is achieved
First let's create the table sequence
CREATE SEQUENCE id
START WITH 1
INCREASE BY 1;
If for example we want to see the structure of the table id, newly created; just execute the following in the console
MariaDB [blog]> describe id;
+-----------------------+---------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------------------+---------------------+------+-----+---------+-------+
| next_not_cached_value | bigint(21) | NO | | NULL | |
| minimum_value | bigint(21) | NO | | NULL | |
| maximum_value | bigint(21) | NO | | NULL | |
| start_value | bigint(21) | NO | | NULL | |
| increment | bigint(21) | NO | | NULL | |
| cache_size | bigint(21) unsigned | NO | | NULL | |
| cycle_option | tinyint(1) unsigned | NO | | NULL | |
| cycle_count | bigint(21) | NO | | NULL | |
+-----------------------+---------------------+------+-----+---------+-------+
From the above table you can notice important details such as the fact that the default numeric value is of type BIGINT
So that as we said that it is going to start in the numbering in 1 and in one more is going to increase, it allows us to generate the progressive number that can be associated, like a primary to a table
Let's create a new table of examples in the mariaDB manager
MariaDB [blog]> CREATE TABLE demo (
-> id BIGINT NOT NULL,
-> name VARCHAR (30),
-> PRIMARY KEY (id));
Finally, when declaring a primary key of autoincrement type it is not necessary to declare it in the insert sentence, when we use a sequence if it is necessary to write the name of the column; as the following example
MariaDB [blog]> INSERT INTO demo (id, name)
-> VALUES
-> (NEXT VALUE FOR id, 'alpha');
How can the previous sequence be observed, to insert the dynamic value generated by the sequence, we invoke the name of the sequence through NEXT VALUE for and at the end the name of the sequence id
Finally, you can obtain the result of our previous sentence, we execute a SELECT regularly on the table and we obtain the following
MariaDB [blog]> SELECT * FROM demo;
+ ---- + ------ +
| id | name |
+ ---- + ------ +
| 1 | alpha |
+ ---- + ------ +
Extra configurations:
Optionally, you can configure the following parameters to a sequence within the mariaDB manager:
minvalue = You can set it 1
maxvalue = Depending on the type of data you choose if it is INT or BIGINT you must check to place a cap that respects the limits of
those data types
Cycle = By default it has the option no cycle, otherwise, once the minimum value starts and the maximum limit is reached, the counter
is restarted and the numbering begins again (provided that the limit
of the data type) possible )

Answer 2

In a word - yes. That feature is available since version 10.3.
See the documentation for the full details.