How To Generate Random test Data In MySQL

Are you tired of manually generating test data for your MySQL tables? If you’re looking for random data generator, look no further! Introducing the MySQL Random Data Generator, a powerful tool designed to effortlessly create random test data for your tables. There are tools that will generate random data for you but they’re not free, though random data generator is free and open source. Importantly it remains in your control.

Why Use MySQL Random Data Generator

• Table-Aware: My tool leverages MySQL’s deep understanding of its own tables to automatically generate data based on table definitions.
• Effortless: Say goodbye to time-consuming perl or shell scripts with loops. Let MySQL handle the data generation efficiently.
• Free and Open Source: Download the tool from my GitHub repository for free. I encourage you to report bugs and contribute to improvements.

I hate generating dummy data, yes I do and I assume you do too! I think that’s the major reason I wrote these MySQL functions and procedures for Generating dummy test data.
I wrote combination of MySQL store routines and procedures that will generate the random test data for you without needing to specify table information. The tool will automatically generate the random data based on the table definition. You can download the data generator tool for MySQL from Github for free. Please consider reporting bugs and improvements.

Download: MySQL Random Data Generator.

People can manage these things with a simple perl / shell script with loops but again that always need your time.
Why can’t MySQL generate data for it’s own table when MySQL better knows the table than anyone else !!

Below are a set of functions and a stored procedure that will make our life easy and of-course it’s free.

Download Random Data Generator Tool For MySQL:

1. Download the SQL code: Generate dummy data for MySQL.
2. Download SQL for generating random data for foreign-key dependent child tables: populate_fk.sql

How to install and generate dummy data:

mysql -uUSER -pPASSWORD DATABASE < populate_dummy_data.txt

How generate test data

To generate test data of 1000 rows for sakila.film table execute following SQL command:

call populate('sakila','film',1000,'N');

MySQL set of functions to get random values generated for individual data-types.

Important Note: This is very first version (2012) of the script consider getting the latest from github.

## MySQL function to generate random string of specified length
DROP function if exists get_string;
delimiter $
CREATE FUNCTION get_string(in_strlen int) RETURNS VARCHAR(500) DETERMINISTIC
BEGIN 
set @var:='';
while(in_strlen>0) do
set @var:=concat(@var,IFNULL(ELT(1+FLOOR(RAND() * 53), 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',' ','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'),'Kedar'));
set in_strlen:=in_strlen-1;
end while;	
RETURN @var;
END $
delimiter ;


## MySQL function to generate random Enum-ID from specified enum definition
DELIMITER $
DROP FUNCTION IF EXISTS get_enum $
CREATE FUNCTION get_enum(col_type varchar(100)) RETURNS VARCHAR(100) DETERMINISTIC
	RETURN if((@var:=ceil(rand()*10)) > (length(col_type)-length(replace(col_type,',',''))+1),(length(col_type)-length(replace(col_type,',',''))+1),@var);
$
DELIMITER ;


## MySQL function to generate random float value from specified precision and scale.
DELIMITER $
DROP FUNCTION IF EXISTS get_float $
CREATE FUNCTION get_float(in_precision int, in_scale int) RETURNS VARCHAR(100) DETERMINISTIC
	RETURN round(rand()*pow(10,(in_precision-in_scale)),in_scale) 
$
DELIMITER ;



## MySQL function to generate random date (of year 2012).
DELIMITER $
DROP FUNCTION IF EXISTS get_date $
CREATE FUNCTION get_date() RETURNS VARCHAR(10) DETERMINISTIC
	RETURN DATE(FROM_UNIXTIME(RAND() * (1356892200 - 1325356200) + 1325356200))
#	Below will generate random data for random years
#	RETURN DATE(FROM_UNIXTIME(RAND() * (1577817000 - 946665000) + 1325356200))
$
DELIMITER ;


## MySQL function to generate random time.
DELIMITER $
DROP FUNCTION IF EXISTS get_time $
CREATE FUNCTION get_time() RETURNS INTEGER DETERMINISTIC
	RETURN TIME(FROM_UNIXTIME(RAND() * (1356892200 - 1325356200) + 1325356200))
$
DELIMITER ;

## MySQL function to generate random int.
DELIMITER $
DROP FUNCTION IF EXISTS get_int $
CREATE FUNCTION get_int() RETURNS INTEGER DETERMINISTIC
	RETURN floor(rand()*10000000) 
$
DELIMITER ;

## MySQL function to generate random tinyint.
DELIMITER $
DROP FUNCTION IF EXISTS get_tinyint $
CREATE FUNCTION get_tinyint() RETURNS INTEGER DETERMINISTIC
	RETURN floor(rand()*100) 
$
DELIMITER ;

## MySQL function to generate random varchar column of specified length(alpha-numeric string).
DELIMITER $
DROP FUNCTION IF EXISTS get_varchar $
CREATE FUNCTION get_varchar(in_length varchar(500)) RETURNS VARCHAR(500) DETERMINISTIC
	RETURN SUBSTRING(MD5(RAND()) FROM 1 FOR in_length)
$
DELIMITER ;

## MySQL function to generate random datetime value (any datetime of year 2012).
DELIMITER $
DROP FUNCTION IF EXISTS get_datetime $
CREATE FUNCTION get_datetime() RETURNS VARCHAR(30) DETERMINISTIC
	RETURN FROM_UNIXTIME(ROUND(RAND() * (1356892200 - 1325356200)) + 1325356200)
$
DELIMITER ;

The MySQL Stored procedure that populates MySQL tables with dummy data

DELIMITER $

DROP PROCEDURE IF EXISTS populate $
CREATE PROCEDURE populate(in_db varchar(50), in_table varchar(50), in_rows int, in_debug char(1)) 
BEGIN
/*
|
| Developer: Kedar Vaijanapurkar
| USAGE: call populate('DATABASE-NAME','TABLE-NAME',NUMBER-OF-ROWS,DEBUG-MODE);
| EXAMPLE: call populate('sakila','film',100,'N');
| Debug-mode will print an SQL that's executed and iterated.
|
*/

DECLARE col_name VARCHAR(100);
DECLARE col_type VARCHAR(100); 
DECLARE col_datatype VARCHAR(100);
DECLARE col_maxlen VARCHAR(100); 
DECLARE col_extra VARCHAR(100);
DECLARE col_num_precision VARCHAR(100);
DECLARE col_num_scale VARCHAR(100);
DECLARE func_query VARCHAR(1000);
DECLARE i INT;

DECLARE done INT DEFAULT 0;
DECLARE cur_datatype cursor FOR
 SELECT column_name,COLUMN_TYPE,data_type,CHARACTER_MAXIMUM_LENGTH,EXTRA,NUMERIC_PRECISION,NUMERIC_SCALE FROM information_schema.columns WHERE table_name=in_table AND table_schema=in_db;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;


SET func_query='';
OPEN cur_datatype;
datatype_loop: loop

FETCH cur_datatype INTO col_name, col_type, col_datatype, col_maxlen, col_extra, col_num_precision, col_num_scale;
#SELECT CONCAT(col_name,"-", col_type,"-", col_datatype,"-", IFNULL(col_maxlen,'NULL'),"-", IFNULL(col_extra,'NULL')) AS VALS;
  IF (done = 1) THEN
    leave datatype_loop;
  END IF;

CASE 
WHEN col_extra='auto_increment' THEN SET func_query=concat(func_query,'NULL, ');
WHEN col_datatype in ('int','bigint') THEN SET func_query=concat(func_query,'get_int(), ');
WHEN col_datatype in ('varchar','char') THEN SET func_query=concat(func_query,'get_string(',ifnull(col_maxlen,0),'), ');
WHEN col_datatype in ('tinyint', 'smallint','year') or col_datatype='mediumint' THEN SET func_query=concat(func_query,'get_tinyint(), ');
WHEN col_datatype in ('datetime','timestamp') THEN SET func_query=concat(func_query,'get_datetime(), ');
WHEN col_datatype in ('float', 'decimal') THEN SET func_query=concat(func_query,'get_float(',col_num_precision,',',col_num_scale,'), ');
WHEN col_datatype in ('enum','set') THEN SET func_query=concat(func_query,'get_enum("',col_type,'"), ');
WHEN col_datatype in ('GEOMETRY','POINT','LINESTRING','POLYGON','MULTIPOINT','MULTILINESTRING','MULTIPOLYGON','GEOMETRYCOLLECTION') THEN SET func_query=concat(func_query,'NULL, ');
ELSE SET func_query=concat(func_query,'get_varchar(',ifnull(col_maxlen,0),'), ');
END CASE;


end loop  datatype_loop;
close cur_datatype;

SET func_query=trim(trailing ', ' FROM func_query);
SET @func_query=concat("INSERT INTO ", in_db,".",in_table," VALUES (",func_query,");");
	IF in_debug='Y' THEN
		select @func_query;
	END IF;
SET i=in_rows;
populate :loop
	WHILE (i>0) DO
	  PREPARE t_stmt FROM @func_query;
	  EXECUTE t_stmt;
	SET i=i-1;
END WHILE;
LEAVE populate;
END LOOP populate;
SELECT "Kedar Vaijanapurkar" AS "Developed by";
END
$
DELIMITER ;

Let me know if you like it and share if you find it useful. Please report any bug.

Conclusion

In the realm of MySQL database management, the process of generating test data has long been a tedious endeavor. My MySQL Random Data Generator seeks to revolutionize this experience by offering a free, efficient, and automated solution. Consider star-ing and forking the repository if you’re keep to contribute.