-- Test system versioned tables in MariaDB.
-- Create two versioned tables: EMPLOYEE and SALARY.
-- Insert and update some values, keep track of timestamps.
-- Then select values from tables at different timestamps.


-- create
CREATE TABLE EMPLOYEE (
  empId INTEGER NOT NULL,

  name TEXT NOT NULL,
  dept TEXT NOT NULL,
  
  PRIMARY KEY (empId),
  INDEX `idx_employee` (empId)
)
WITH SYSTEM VERSIONING
-- PARTITION BY SYSTEM_TIME INTERVAL 1 MONTH  (
--   PARTITION p_hist HISTORY,
--   PARTITION p_cur CURRENT
-- );
;

-- create
CREATE TABLE SALARY (
  id INTEGER AUTO_INCREMENT NOT NULL,
  empId INTEGER NOT NULL,

  state TEXT NOT NULL,
  salary NUMERIC,

  PRIMARY KEY (id),
  INDEX `idx_employee` (empId),
  CONSTRAINT `fk_employee` FOREIGN KEY (empId)
    REFERENCES EMPLOYEE(empId)
    ON DELETE CASCADE ON UPDATE CASCADE
)
WITH SYSTEM VERSIONING
-- PARTITION BY SYSTEM_TIME INTERVAL 1 MONTH  (
--   PARTITION p_hist HISTORY,
--   PARTITION p_cur CURRENT
-- )
;

-- **NOTE**: FOREIGN_KEY does not work with PARTITION


-- insert
INSERT INTO EMPLOYEE VALUES (00010001, 'Clark', 'Sales');
INSERT INTO EMPLOYEE VALUES (00020001, 'Dave', 'Accounting');
INSERT INTO EMPLOYEE VALUES (00030001, 'Ava', 'Sales');

INSERT INTO SALARY VALUES (0, 00010001, 'TX', '125000');
INSERT INTO SALARY VALUES (0, 00020001, 'AZ', '120000');
INSERT INTO SALARY VALUES (0, 00030001, 'WA', '85000');

-- sleep
SELECT SLEEP(1) AS '';

SET @TIMESTAMP1 = NOW();


-- update
UPDATE EMPLOYEE SET dept = 'Accounting' WHERE empId = 00010001;
UPDATE SALARY SET salary = '150000' WHERE empId = 00010001;

-- sleep
SELECT SLEEP(1) AS '';

SET @TIMESTAMP2 = NOW();


-- insert
INSERT INTO EMPLOYEE VALUES (00040001, 'Jim', 'IT');
INSERT INTO SALARY VALUES (0, 00040001, 'WA', '133700');

-- sleep
SELECT SLEEP(1) AS '';

SET @TIMESTAMP3 = NOW();


-- fetch current
select '*** EMPLOYEE names for Sales dept ***' AS '';
SELECT name, dept FROM EMPLOYEE WHERE dept = 'Sales';

select '*** joined EMPLOYEE names and SALARY values ***' AS '';
SELECT name, state, dept, salary FROM SALARY
  INNER JOIN EMPLOYEE on (EMPLOYEE.empId = SALARY.empId);

-- **NOTE**: fetches current state, does not include versioning timestamps


-- fetch all
select '*** all EMPLOYEE entries with versioning ***' AS '';
SELECT *, ROW_START, ROW_END FROM EMPLOYEE
  FOR SYSTEM_TIME ALL;

select '*** all SALARY entries with versioning ***' AS '';
SELECT *, ROW_START, ROW_END FROM SALARY
  FOR SYSTEM_TIME ALL;

-- **NOTE**: fetches current state and includes versioning timestamps


-- fetch for time
SELECT * FROM information_schema.USER_VARIABLES ORDER BY VARIABLE_NAME;

select '*** joined entries at timestamp #1 ***' AS '';
SELECT name, salary, dept FROM EMPLOYEE FOR SYSTEM_TIME AS OF @TIMESTAMP1
  INNER JOIN SALARY FOR SYSTEM_TIME AS OF @TIMESTAMP1 on (EMPLOYEE.empId = SALARY.empId);

select '*** joined entries at timestamp #2 ***' AS '';
SELECT name, salary, dept FROM EMPLOYEE FOR SYSTEM_TIME AS OF @TIMESTAMP2
  INNER JOIN SALARY FOR SYSTEM_TIME AS OF @TIMESTAMP2 on (EMPLOYEE.empId = SALARY.empId);

select '*** joined entries at timestamp #3 ***' AS '';
SELECT name, salary, dept FROM EMPLOYEE FOR SYSTEM_TIME AS OF @TIMESTAMP3
  INNER JOIN SALARY FOR SYSTEM_TIME AS OF @TIMESTAMP3 on (EMPLOYEE.empId = SALARY.empId);

-- **NOTE**: fetches state at given time
-- **NOTE**: when using JOIN one must specify timestamp again

MariaDB online editor

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About MariaDB

MariaDB is a community developed, open source relational database management system.

Key Features

  • Development was led by few of the original developers of MySQL
  • It's an improved version of MySQL with numerous inbuilt powerful features,security, performance improvements compared to MySQL.
  • High compatibility with MySQL and thus it has exact matching with MySQL APIs and commands with new features.
  • New storage engine, Aria
  • MariaDB has been supported in Amazon RDS service and Microsoft Azure.
  • Intended to remain free and open source software under GPL, BSD or LGPL licenses.
  • Supports different programming languages and runs on different operating systems.

Syntax help

1. CREATE

CREATE command is used to create a table, schema or an index.

Syntax:

         CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

2. ALTER

ALTER command is used to add, modify or delete columns or constraints from the database table.

Syntax

ALTER TABLE Table_name ADD column_name datatype;

3. TRUNCATE:

TRUNCATE command is used to delete the data present in the table but this will not delete the table.

Syntax

TRUNCATE table table_name;

4. DROP

DROP command is used to delete the table along with its data.

Syntax

DROP TABLE table_name;

5. RENAME

RENAME command is used to rename the table name.

Syntax

ALTER TABLE table_name1 RENAME to new_table_name1;

6. INSERT

INSERT Statement is used to insert new records into the database table.

Syntax

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

7. SELECT

Select statement is used to select data from database tables.

Syntax:

SELECT column1, column2, ...
FROM table_name;

8. UPDATE

UPDATE statement is used to modify the existing values of records present in the database table.

Syntax

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

9. DELETE

DELETE statement is used to delete the existing records present in the database table.

Syntax

DELETE FROM table_name where condition;