MySQL Schema Maintenance

MySQL schema
maintenance

Giuseppe Maxia
MySQL Community Team Lead
This work is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License.

Thursday, 03 December 2009

about me - Giuseppe Maxia
 a.k.a. The Data Charmer
 MySQL Community Team Lead
 Long time MySQL hacker
 Formerly, database consultant, designer, coder.
 A passion for QA
 An even greater passion for open source
 ... and community
 Passionate blogger
 http://datacharmer.blogspot.com


Schema what?

In a relational database, the schema defines the tables,
the fields in each table, and the relationships between
fields and tables.
http://en.wikipedia.org/wiki/Schema_(database)


tables


tables

table name

column column column


tables
CREATE TABLE employees
(
ID INT NOT NULL,
name VARCHAR(20), name
table

salary INT, column column column
PRIMARY KEY (ID)
)


relationship
departments employees

ID INT ID INT

name varchar (10) name varchar (10)

salary INT

dept_ID INT


relationship

ID INT ID INT


salary INT

1
dept_ID INT


relationship

ID INT ID INT


salary INT

1
dept_ID INT
many


relationship
customer

ID INT

name varchar (10)

sales
cust_ID INT
emp_ID INT
s_date DATE
amount DECIMAL employees

ID INT

name varchar (10)

salary INT

dept_ID INT

relationship
customer

ID INT

name varchar (10)

sales
cust_ID INT
emp_ID INT
s_date DATE

ID INT

name varchar (10)
1
salary INT

dept_ID INT

relationship
customer
many
ID INT

name varchar (10)

sales
cust_ID INT
emp_ID INT
s_date DATE

ID INT

name varchar (10)
1
salary INT

dept_ID INT

relationship
customer
many
ID INT
many to
name varchar (10)
many
sales
cust_ID INT
emp_ID INT
s_date DATE

ID INT

name varchar (10)
1
salary INT

dept_ID INT

Main actors

• Production
• Development
• Stage
• Test


Production database

• You must have one

Development database

• Where you create new things

Test database

• Where you experiment crazy ideas

Stage database

• Where you test before deploying to
production


Schema maintenance
actions

• Reverse engineering
• Forward engineering
• Synchronization


Reverse Engineering


Reverse Engineering

DDL
dept_emp
department
dept_manager
employees
titles
salaries


Forward Engineering


Forward Engineering

DDL
dept_emp
department
dept_manager
employees
titles
salaries


Forward Engineering
.
ti ve
! truc
G e s
IN is d
N g
DDL A
R n
dept_emp
W ee ri
department
g in
dept_manager
employees d
en
a r
rw
titles
o salaries
F


Synchronization


How it works

yes
Development OK? Production
no no

yes
OK? Stage
Test


How else it works

Development Production

• Partition
adjustment
• Dynamic schemas
Test Stage
• Hot ﬁxes

What happens in
between

Development
no

OK?
Test


What happens in
between

Development
no What now?

OK?
Test


What happens in
between

Development
no What now? Wrong
schema here

OK?
Test


What happens in
between

Development
no What now? Wrong
schema here

OK? REWIND?
Test


Schema maintenance: how to

1. Poor man's way

How poor is the poor man?
• only command line access
• No Perl, PHP, or Python
• Can't install anything

• Command line access
• Perl or Python available
• Can install modules

• GUI
• Can install everything

ELY • only command line access
EM R
TR O
EX PO

• Perl or Python available

• GUI

EM R
TR O
EX PO

OR • Perl or Python available
PO

• GUI

EM R
TR O
EX PO

OR • Perl or Python available
PO

RI CH • GUI

so, the extremely poor
man's way ...
HOST 1 HOST 2


man's way ...
HOST 1 HOST 2
get the Development Production
schema

TEXT
FILE


man's way ...
HOST 1 HOST 2
get the Development Production get the
schema schema

TEXT TEXT
FILE FILE


man's way ...
HOST 1 HOST 2
schema schema

TEXT TEXT
diff
FILE FILE


man's way ...
HOST 1 HOST 2
schema schema

TEXT TEXT
diff
FILE FILE

then … uh … ﬁgure out how to continue

the poor man's way ...
HOST 1 HOST 2

get the get the
schema schema

TEXT diff TEXT
FILE FILE
Perl Script


the poor man's way ...
HOST 1 HOST 2

get the get the
schema schema

TEXT diff TEXT
FILE FILE
Perl Script
TELLS YOU WHAT TO DO

not so poor man's way ...
HOST 1 HOST 2

DOES A LOT OF THINGS

Python Script

http://schemasync.org

not so poor man's way ...
HOST 1 HOST 2

DOES A LOT OF THINGS

Python Script

http://schemasync.org
WARNING: doesn't deal with partitions

The rich man

http://aquafold.com


The rich man

http://aquafold.com

WARNING: doesn't deal with partitions

MySQL Workbench

http://wb.mysql.com


Schema and model


Schema and model

DDL
dept_emp
department
dept_manager
employees
titles
salaries


Physical schema

implemented
in a speciﬁc DBMS


Physical schema

DDL
dept_emp
department
dept_manager implemented
employees in a speciﬁc DBMS
titles
salaries


Conceptual model

DBMS agnostic


MySQL Workbench
basics


Creating tables (1)


Creating tables (2)


Creating tables (3)


Creating tables (4)


Creating tables (5)


database connections(1)


database connections(2)


Reverse engineering in
the old world


Reverse engineering in
the old world
show create table departmentsG

Create Table: CREATE TABLE `departments`

(

`dept_id` int(10) unsigned NOT NULL,

`department` char(30) NOT NULL,

PRIMARY KEY (`dept_id`),

KEY `department` (`department`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1

1 row in set (0.00 sec)


Reverse engineering (1)


forward engineering in
the old world
mysqldump --host=development -B
--no-data crosstab > crosstab.sql

mysql --host=stage < crosstab.sql


Forward engineering (1)


synchronization in the
old world


Synchronization (1)


Synchronization (2)


Synchronization (3)


Synchronization (4)


Synchronization (5)


Synchronization (6)


More goodies

• MySQL Workbench 5.2 (Beta) - live demo


Thanks
Let's talk!


MySQL Schema Maintenance

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