Dependency Tag

It would be very useful if we could add a tag to a script that says I’m dependent on script X to run before me.  Of course you should be able to put a list of dependencies not just one.  This would allow us to handle dependency order in a more fine grained way.  Right now I use a mix of Liquibase config files with the script names hard coded in the correct order to get the correct table order.  Is this something that is possible? And does it pose any problems?



I’m not sure what the differences between this proposal and the existing tag?

Sounds like you’d be best off using Ant (this


My understanding is that will just give me a boolean that a object exists or doesn’t, it won’t actually let me say if false please go and execute script xyz.sql as part of the normal liquibase build process.

The difference is with the new approach is the dependencies you list should be executed for you if it hasn’t already been executed.  For example currently if I have three tables animal, classification, animal_classification and my liquibase config is setup to point to a directory called /tables with a script for each table in a raw sql file liquibase will grab animal then  animal_classification followed by classification and fail because of the fks on animal_classification  depending on animal and classification . The desired order should be  animal, classification, and then animal_classification. Under the new approach I would list the  dependencies in the  animal_classification sql script.  Something like  --dependsOn animal.sql, classification.sql  also these could be stored procedures, views, index etc etc not just tables.

Imagine you have a existing database with 1,800 tables, 4,000 stored procedures, hundreds of view yadayada how do propose you script out your existing database and build a clean empty database for development with liquibase without getting hundreds if not thousands of  dependency error messages. In the database order matters or else you can’t execute your scripts.  Now I don’t mind creating my own process that scripts out my existing structure and adds the tag  dependencies that I described. I just want liquibase to be able to read this tag data and run the scripts in that order. This allows me to still name my scripts the same as the object name and not have to create a hodge-podge of liquibse config files to mimic this behavior.  

If I’m missing something please let me know I would love to be wrong on this.

Thanks for the comment Laird. 

Ant can do this and that’s basically what I’m asking for in liquibase. In the database dependency order matters so I don’t see why liquibase shouldn’t be expected to handle this.  Basically if I go the Ant route that would imply liquibase is not needed at all as you could just use Ant so why have liquibase at all?  I’ll tell you why because liquibase focuses on database builds and does a really great job. Ant is such a general build tool that you can do almost anything at the expense of creating a bloody mess.