A tool and a language that help generating random complex database instance based on predefined rules
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README.md

NAME

Cheater - Generate random database based on rules

Table of Contents

VERSION

This document describes Cheater 0.10 released on June 24, 2011.

DESCRIPTION

Cheater is a tool that can generate random database based on rules. It was widely used within the LineZing team of Taobao.com.

Compared to other similar tools, cheater has the following advantages:

  • it can automatically handle the association and foreign key restrictions among data tables, so it's the real "database instance generator".
  • It defines a SQL-like little language to specify the data model that we want to generate from.
  • It supports powerful {a, b, c} discrete enumation sets, numerical/time/date interval syntax a..b, Perl regular expressions /regex/, constant values 'string', 1.32, and etc, to describe the value range of data table field.
  • It can generate JSON or SQL insert statements to ease importing to RDMBSes like MySQL/PostgreSQL.

Below is a very simple example to demonstrate its basic usage.

First of all, we create a .cht input file in our working directory (say, under ~/work/), in order to describe the data model that we want to geneate data from. Assuming we have a company.cht file like this:

# Empolyee table
table employees (
    id serial;
    name text /[A-Z]a-z{2,5} [A-Z]a-z{2,7}/ not null unique;
    age integer 18..60 not null;
    tel text /1[35]8\d{8}/;
    birthday date;
    height real 1.50 .. 1.90 not null;
    grades text {'A','B','C','D','E'} not null;
    department references departments.id;
)

# Department table
table departments (
    id serial;
    name text /\w{2,10}/ not null;
)

10 employees;
2 departments;

Here we're using the little language (or DSL) defined by cheater itself. It's semantics is self-explanatory. In particular, the last two lines state that we want to generate 10 rows of data for the employees table and 2 rows for the departments table.

And then, we use the cht-compile command to compile our company.cht file to generate a random database instance:

$ cht-compile company.cht
Wrote ./data/departments.schema.json
Wrote ./data/departments.rows.json
Wrote ./data/employees.schema.json
Wrote ./data/employees.rows.json

We see that it generates two .json data files for the departments and employees tables, respectively. For example, the data/emplyees.rows.json file on my machine resulting from a particular run looks like this:

$ cat data/employees.rows.json
[["id","name","age","tel","birthday","height","grades","department"],
["7606","Kxhwcn Cflub",54,"15872171866","2011-04-01","1.67276","D","408862"],
["63649","Whf Iajgw",55,"13850771916",null,"1.65297","E","844615"],
["348161","Nnwe Obfkln",27,"15801601215","2011-03-06","1.69275","D","408862"],
["353404","Shgpak Xvqxw",28,"15816453097",null,"1.67796","A","408862"],
["445500","Bdt Mhepht",47,"13855517847",null,"1.89943","C","844615"],
["513515","Ipsa Mcbtk",25,"13874017694","2011-01-06","1.79534","A","844615"],
["658009","Lboe Etqo",27,null,"2011-04-14","1.85162","E","408862"],
["716899","Gey Elacflr",18,"15804516095","2011-02-27","1.75681","A","844615"],
["945911","Hsuz Qcmky",39,"13862516775","2011-05-31","1.75947","B","408862"],
["960643","Qbmbe Ijnbqsb",24,"15872418765","2011-04-11","1.78864","B","844615"]]

These are the "row data". On the other hand, ./data/employees.schema.json is the table structure definition for the employees table. It looks like this on my side:

[{"attrs":[],"name":"id","type":"serial"},
{"attrs":["not null","unique"],"name":"name","type":"text"},
{"attrs":["not null"],"name":"age","type":"integer"},
{"attrs":[],"name":"tel","type":"text"},
{"attrs":[],"name":"birthday","type":"date"},
{"attrs":["not null"],"name":"height","type":"real"},
{"attrs":["not null"],"name":"grades","type":"text"},
{"attrs":[],"name":"department","type":"serial"}]

We can generate SQL DDL statement files accepted by RDBMSes like MySQL or PostgreSQL from the .schema.json files like this:

$ cht-schema2sql data/employees.schema.json
Wrote ./sql/employees.schema.sql

The output .sql file looks like this:

$ cat ./sql/employees.schema.sql
drop table if exists employees;
create table employees (
    id serial primary key,
    name text not null unique,
    age integer not null,
    tel text,
    birthday date,
    height real not null,
    grades text not null,
    department serial
);

If we want to eliminate the drop table statement in the resulting SQL file, we can specify the -n option while running the cht-schema2sql utility. For instance,

$ cht-schema2sql -n data/employees.schema.json
Wrote ./sql/employees.schema.sql

At last, we can use the cht-rows2sql command to convert those .rows.json data files to .sql files that are ready for relation database systems to import the "row data".

$ cht-rows2sql data/*.rows.json
Wrote ./sql/departments.rows.sql
Wrote ./sql/employees.rows.sql

The sql/departments.rows.sql looks like this on my side:

$ cat sql/departments.rows.sql
insert into departments (id,name) values
(408862,'dJRq7LCXL'),
(844615,'G_m9Nkh3q');

To prevent the resulting data from conflicting with extra unique key restrictions in the targeting RDMBS table, we can use the -r option to make cht-rows2sql generate SQL replace statements to work-around this:

$ cht-rows2sql -r data/*.rows.json
Wrote ./sql/departments.rows.sql
Wrote ./sql/employees.rows.sql

Now we're ready to import the random data into database systems like MySQL!

$ mysql -u some_user -p dbname < sql/departments.rows.sql

For now, cheater is still in active development and lacking comprehensive documentation, the most complete documentation is its (declarative) test suite:

http://github.com/agentzh/cheater/tree/master/t/

Open one of those .t files, you can see lots of declarative test cases, like these:

=== TEST 5: datetime range domain
--- src
table cats (
    birthday datetime 2010-05-24 03:45:00..2010-06-05 18:46:05 not null;
)

5 cats;
--- out
cats
      birthday
      2010-06-02 14:59:02
      2010-06-04 03:31:00
      2010-06-03 01:51:41
      2010-05-28 19:29:34
      2010-06-02 13:31:38

INSTALLATION

Currently we require at most perl 5.12.x and at least perl 5.10.1. Neither newer nor older versions of perl will not work.

perl Makefile.PL
make
make test
make install

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SOURCE REPOSITORY

The source repository of this project is on GitHub:

http://github.com/agentzh/cheater/

If you have found any bugs or feature request, feel free to create tickets on the GitHub issues page:

http://github.com/agentzh/cheater/issues

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AUTHOR

Yichun "agentzh" Zhang (章亦春) <agentzh@gmail.com>, CloudFlare Inc.

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COPYRIGHT & LICENSE

Copyright (c) 2010-2016, Yichun Zhang (agentzh), CloudFlare Inc.

This module is licensed under the terms of the BSD license.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of the Taobao Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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SEE ALSO

Parse::RandGen::Regexp, Data::Random.

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