Programming stuff: Bash, Linux, SQL and Java

below is a case with only 2 varchar columns and an int
create table example(
id int unsigned auto_increment not null,
column1 varchar(200),
column2 varchar(200),
column3 int unsigned,
primary key(id)
);

mysql -u USERNAME -pPASSWORD DBNAME -e "insert into example (column1,column2,column3) values (char(FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20))),char(FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20)),FLOOR(65 + (RAND() * 20))),FLOOR(1000 + (RAND() * 1000)))"

it will generate uppercase strings and integers between 1000 and 2000 ,and insert them into the table.
it is important to put unsigned, thus you will increase the range for the primary key. you don’t need any negative values for id anyway.