The diff
and diffChangelog
commands are used to inspect the difference between the source
and target
database. the Snapshot
command generates the state of the current database
in the file, this file can also be used with diff
and diffChangelog
instead of the actual target database.
execute the below script into the database
create database appleDbTarget;
use appleDbTarget;
create table apple (apple_id bigint not null AUTO_INCREMENT , apple_name varchar(255), available CHAR(1), current_date_time datetime default now(), primary key (apple_id), CONSTRAINT uqniue_apple_name UNIQUE (apple_name)) engine=InnoDB;
insert into apple (apple_name, available, current_date_time) values ("Macintosh", 'Y', now());
insert into apple (apple_name, available, current_date_time) values ("Fuji", 'Y', now());
commit;
create database appleDbSource;
commit;
liquibase.properties (update changeLog File file format with SQL, XML, YAML, JSON as per changelog.mysql.)
liquibase.command.url:jdbc:mysql://localhost:3306/appleDbTarget?createDatabaseIfNotExist=true&autoReconnect=true&useSSL=false&allowPublicKeyRetrieval=true
liquibase.command.username: root
liquibase.command.password: rootroot
snapshotFormat=json
outputFile=TargetDbSnapshot.json
To create a snapshot
of the current database, execute the command
liquibase snapshot
it will create a file named TargetDbSnapshot.json
Compare Snapshot with another Database
The snapshot
command saves the current state of the database
in JSON file format
. Since this JSON file
contains the exact state of the database
, it can be used to compare the state with another database
via diff
or diffChangelog
command.
To compare the generated TargetDbSnapshot.json
file with the actual database, update the liquibase.properties
changeLogFile=changelog.mysql.xml
# target db
liquibase.command.url=offline:mysql?snapshot=TargetDbSnapshot.json
# source db
liquibase.command.referenceUrl =jdbc:mysql://localhost:3306/appleDbSource?createDatabaseIfNotExist=true&autoReconnect=true&useSSL=false&allowPublicKeyRetrieval=true
liquibase.command.referenceUsername= root
liquibase.command.referencePassword= rootroot
To generate the difference in missing objects
between the source
and target
databases, run the command
liquibase diff
To generate the ChangeLog
of missing objects between the source
and target
databases, run the command
liquibase diffChangeLog