LBF101 Creating an XML Changelog

[00:00:00]foreign boxland the founder of liquibase throughout this course I will be demonstrating different functionality to help you learn to use Liquid base now that you understand the concepts around changelogs and change sets I'd like to demonstrate how to build your first XML change log before I dive into that there's a couple reasons for using XML as the the format primarily it's going to come from the stand from the side that by using XML and similarly with Json and yaml formats it gives you an ability to specify what you want liquids to do to the database and then liquid base figures out the the specific SQL and how to how to take advantage of that um that can give you some good advantages around database Independence as well as being able to unlock some liquid-based functionality around being able to have a liquid base know how to roll back some of those changes and some of that um you know because it is just a regular XML file you can use the editor of your choice although you know something some sort of IDE that does intellisense is is always nice um so um starting out you know the first thing you're going to need to do is create your XML file with your sort of starting starting header and and starting um uh root tag and and setup um so liquid-based change logs are going to use this database change log as the uh root element uh we have a schema here that we Define uh we can either specify the specific version liquid-based version to work with for the xsd or you can use Dash latest which is is usually the easiest route and it's going to be the the version that works with uh what you the version of liquid base that you're using uh so once you have your your starting file here the first thing to do is to add the change steps uh so I'm going to create a starting change set um in your change sets you have to specify an ID which is just any string I can do anything you want um the author uh that can also be any string that you want um but is is useful to kind of keep it at least isolated to you um uh to the the particular person um and then within the change set you're able to specify uh the you know the the the change that you change the changes that you want to do um this is where the intellisense with XML can be nice I can say I want to create a table I'm going to call it test one I'm going to make a column that's a ID a type int and I have with this change set in here now I can run run this against liquid base liquid base is going to take the pieces that are in there and um figure out the correct SQL for my database and run that against the data and run that against the database when I do a liquid base update when I'm wanting to make some additional changes to the database it's just a matter of adding additional change sets in here I can do one that's going to do add column to my test one table I'm going to make now a name with a bar with a type of a barcare of 20.

[00:03:10]and now when I run liquobase it will it will add that that additional column there finally just to kind of show this example here too you can also just specify directly the SQL that you want to run so I can say create table test two with an ID event and you know that that lets you specify exactly what you want and um you know including a lot of database specific uh type of features and Clauses in your statement that maybe aren't aren't handled by the the generic change functionality there uh so once you have your once once I've made my changelog file it's simply a matter of saving it here to my uh change log or my project directory and my changelog file is ready to be deployed