Why is --driver required?

Liquibase Users
#1

Shouldn’t Liquibase be able to use DriverManager to find the proper driver based off the URL?

Best,
Laird

–
http://about.me/lairdnelson

#2

Yes; I’m quite familiar with the jdbc.drivers property (documented in the same class).

I understand this property is convenient, and is nice to have, but should it be required?

Best,
Laird

–
http://about.me/lairdnelson

#3

The JDBC driver class must be loaded and linked (that results in invocation of the static initializer of the driver class) so that it can register itself with DriverManager. Only after a driver class is registered DriverManager can find the class.


This also explains why we need Class.forName(driverClassName) before calling DriverManager.getConnection() when using vanilla JDBC.


Hence, we must know the Driver class name before we can obtain a connection. HTH.


Shantanu


P.S.: It is of course possible to “guess” the driver class name based on the JDBC URL, but that sounds like an exercise in limited versus non-trivial.

#4

It’s marked as required here: http://liquibase.org/manual/command_line#required_parameters

–
http://about.me/lairdnelson

#5

It looks like --driver is optional, as it should be. If you don’t specify it it sets it off the defaultDriver property on the liquibase Database objects.


Where are you seeing it required?


Nathan

#6

Ok, thanks. I’ll get that doc changes. The code doesn’t look like it’s enforcing that.


Nathan