L1=Junior/fresher dba, having 1-2 year exp.
L2=Intermediate dba, having 2+ to 4 year exp.
L3=Advanced/Expert dba, having 4+ to 6 year exp..
But, this is not an official term, nor it is somewhere documented in any IT policy, rather may be in your region opposite saying/direction exists.
As far as I have seen....
L1: monitoring databases and handle very basic tasks in database.
L2: maintaing database and do more advance administrative tasks and solve the problem raised by L1 people or problems not able to solve by L1
L3:when there is very critical work then they plan the work so that it work will be done carefully or they came into play in disaster recovery scenarios and also plan architecture of database according to requirement.
L1:people are basically do night shifts ;-)
just a practical tone :-)
Briefly explain L1,L2,L3 supports of Oracle DAB responsibilities
"When I use a word," Humpty Dumpty said in rather a scornful tone, "it means just what I choose it to mean -- neither more nor less."
(Lewis Carroll - Through the Looking Glass)
And so it is with job titles.
Even though we work in a technical industry, not every term you see has a universal, fixed, immutable, technical meaning.
Job titles mean only and exactly what the organization using them intends for them to mean.
My first two jobs in IT were in shops that had exactly the same set of job titles for Programmers --
- Programmer/Analyst I
- Programmer/Analyst II
- Programmer/Analyst III
In the first shop, the Programmer/Analyst I was the most junior of the three.
In the second shop, - Programmer/Analyst I was the most senior of the three.