State-based or migration- based database development? A review of the pros and cons.
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Transcript of State-based or migration- based database development? A review of the pros and cons.
State-based or migration-based
database development?
A review of the pros and cons
#worksOnMyMachine
Whoa!Deployment fail!
SQL Relay Birmingham29th October 2014
@_AlexYates_
workingwithdevs.com
uk.linkedin.com/in/alexanderyates
SQL Relay Newcastle27th October 2014
@_AlexYates_
workingwithdevs.com
uk.linkedin.com/in/alexanderyates
SQL Relay Birmingham29th October 2014
@_AlexYates_
workingwithdevs.com
uk.linkedin.com/in/alexanderyates
#devops
ProductionDBA
ChiefArchitect
.NET Devteam lead
(Partnersin crime)
SQL Devteam lead
Reliability Safe
deployments Fire prevention
over firefighting
Visibility Visualise
pipeline Better
coordination
DevOps DBA + devs
work together Automation Agility
1 2 3
Goals for project
There’s more than one way to skin a cat!
V1 V2
Migrations based solutions
V1 V2
State based solutions
V1 V2
“There's nothing more reliable than keeping track of exactly the
scripts you intend to run, and running them, without trying to
compare state and guess.” Paul Stovell, built Octopus Deploy
“There's nothing more reliable than keeping track of exactly the
scripts you intend to run, and running them, without trying to
compare state and guess.” Paul Stovell, built Octopus Deploy
“As soon as you have multiple changes on a single aspect of an object, ordering and the ability to detect which change
needs to be made gets very complicated.”
Gert Drapers, built DataDude
Demo: the happy path!
SOURCE CONTROL
CONTINUOUSINTEGRATION
AUTOMATEDDEPLOYMENT
11
2 Table rename Table ‘foo’ is to be renamed ‘bar’
Edit stored procedure Myproc to select col2 from table ‘foo’
(currently it selects only col1)
Task
0124_edit_sproc.sql
ALTER PROCEDURE myprocAS BEGIN SELECT col1, col2 FROM table_foo END
0124_edit_sproc.sql 0125_table_rename.sqlEXEC sp_rename 'table_foo', 'table_bar‘
ALTER PROCEDURE myprocAS BEGIN SELECT col1 FROM table_bar END
ALTER PROCEDURE myprocAS BEGIN SELECT col1, col2 FROM table_foo END
0124_edit_sproc.sql 0125_table_rename.sqlEXEC sp_rename 'table_foo', 'table_bar‘
ALTER PROCEDURE myprocAS BEGIN SELECT col1 FROM table_bar END
ALTER PROCEDURE myprocAS BEGIN SELECT col1, col2 FROM table_foo END !
Conflicts easily missed Changes overwritten
Order matters Last script wins
To review changes Much reading, but very
important to get code right
The problem with migrations
V123
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_foo
!
V123
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_foo
V124
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1, col2 FROM table_foo
V123
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_foo
V124
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1, col2 FROM table_foo
V125
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_bar
V123
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_foo
V124
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1, col2 FROM table_foo
V125
myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_bar
!
REVISION 123 REVISION 124
table_foo.sqlCREATE TABLE table_foo(col1 NVARCHAR(max), col2 NVARCHAR(max)) myproc.sqlCREATE PROCEDURE myprocAS SELECT col1 FROM table_foo
table_bar.sqlCREATE TABLE table_bar(col1 NVARCHAR(max), col2 NVARCHAR(max)) myproc.sqlCREATE PROCEDURE myprocAS SELECT col1, col2 FROM table_bar
Diff script:
DROP TABLE table_foo
CREATE TABLE table_bar(col1 NVARCHAR(max), col2 NVARCHAR(max))
ALTER PROCEDURE myprocAS SELECT col1, col2 FROM table_bar
The problem with state
Diff script
DROP TABLE table_foo
CREATE TABLE table_bar(col1 NVARCHAR(max), col2 NVARCHAR(max))
ALTER PROCEDURE myprocAS SELECT col1, col2 FROM table_bar
!
The problem with state
Script
DROP TABLE table_foo
CREATE TABLE table_bar(col1 NVARCHAR(max), col2 NVARCHAR(max))
ALTER PROCEDURE myprocAS SELECT col1, col2 FROM table_bar
Need to understand your tool It should be obvious to you that
your tool won’t work
What is the Plan B / override? Because one day you’ll need it
Test for data loss Automatically (naturally)
The problem with state
One more thing…
State
Easier (less control)
Better for sprocs/functions
Better for large/distributed teams
Better for frequent changes
Better for dependency nightmares
Drift: rolled back
Migrations
More control (harder/needs discipline)
Better for data migrations
Better for small teams
Better for infrequent changes
Better for simple data stores
Drift: ignored
So what is better?
State (+migrations)
SSDT pre/post deploy scripts
Redgate migrations
Migrations (+state)
ReadyRoll ‘deploy changes’
Best of both worlds?
Reliability Safe
deployments Fire prevention
over firefighting
1
Goals for project
Reliability Safe
deployments Fire prevention
over firefighting
Visibility Visualise
pipeline Better
coordination
1 2
Goals for project
Reliability Safe
deployments Fire prevention
over firefighting
Visibility Visualise
pipeline Better
coordination
DevOps DBA + devs
work together Automation Agility
1 2 3
Goals for project
@_AlexYates_
workingwithdevs.com/delivering-databases-migrations-vs-state
uk.linkedin.com/in/alexanderyates
Image sourcesAuthor Source Information
Chiltepinster Wikimedia Commons Mocking Bird Argument.jpg – Wikimedia Commons. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Source on Wikimedia Commons: “Own work”
Tableatny Wikimedia Commons Athlete at Starting block.jpg – Wikimedia Commons. This file is licensed under the Creative Commons Attribution 2.0 Generic license. Source on Wikimedia Commons: “BXP135671”
Henry Mühlpfordt Flickr CERN Atlas Control Room 2010-07-01 – Flickr. This file is licensed under the Creative Commons Attribution-ShareAlike 2.0 Generic license.
Department for Business, Innovation and Skills
Flickr Toyota’s new Auris – Flickr. This file is licensed under the Creative Commons Attribution-NoDerivs 2.0 Generic license.
Stephen Wolfe Flickr Violinists – Flickr. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
Akira Hsu Flickr The Micro Four Thirds Logo by Empire Elite Stormtroopers - for the great “Micro Four Thirds Day” – Flickr. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
Nils Rinaldi Flickr Hippo fight 2/3 – Flickr. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
My own collection All pictures are either of me, taken by friends/colleagues, or taken by me
All pictures on about me slide, including kitten, and team at Farm Credit Services of America (FCSA). FCSA have allowed me/Redgate to reference the visit in presentations/marketing material etc.
Memegenerator.net Memegenerator.net I don’t always edit database. Content designed to be shared and delivered with credit to memegenerator.net.
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