Javers - foreign key constraint fails with mysql - foreign-keys

Question

I am new in javers. Started a POC for my application but getting SQL_EXCEPTION while committing, due to 'last_insert_id()' function of mysql returns '0'.
What I did:
Added started in spring boot maven (javers core & javers mysql)
Created a connection with my database schema
Got all the tables in may db (jv_global_id, jv_commit etc..)
Problem:
I am using spring boot 2.0 with mysql version 5.7 I debugged the
problem in deep and found that When Javers code
'org.javers.repository.sql.session.Session.java' method
'executeInsertAndGetSequence' line no 40, tries to find primary key it
return as zero '0'. As per code, mysql dialect does not support
sequences so it generate a value from keyGenerator using mysql funtion
'last_insert_id()' at eventually it returns zero.
I got following error:
SQL_EXCEPTION: Cannot add or update a child row: a foreign key constraint fails (`jv_snapshot`, CONSTRAINT `jv_snapshot_commit_fk` FOREIGN KEY (`commit_fk`) REFERENCES `jv_commit` (`commit_pk`))\nwhile executing sql: INSERT INTO thinkhr_portal.jv_snapshot ( type, global_id_fk, commit_fk, version, state, changed_properties, managed_type ) VALUES ( ?,?,?,?,?,?,? )
I wonder, if javers does not support mysql version 5.7 or there is something else I need to take care in my javers configuration.

Answer 1

I ran into the same issue, and it was due to creating a new connection every time in the ConnectionProvider. Javers was trying to get the commit id by running select last_insert_id(), and in the new connection, it always returns 0.
You want your connection provider to be something like this:
ConnectionProvider connectionProvider = new ConnectionProvider() {
private Connection conn;
#Override
public Connection getConnection() throws SQLException {
if (conn == null) {
conn = buildNewConnection();
}
return conn;
}
};