Question : mySQL API or SQL lite?

this a general question on SQL lite and mySQL.
I have an old program which has its own binary database file.
I am thinking of upgrading this database to SQL-based database.
I need to add some code to make the SQL-based databse in my old program.

Someone suggested mySQL API while some other people suggested SQL lite, which they said I can make the server built-in my application program.
Which option is better for my upgrading work? SQL lite or mySQL API?
I need some technical advice on this. what are pros and cons of these two techs?
min

Answer : mySQL API or SQL lite?

Yes sql-lite can be transformed into mysql (eg. generate SQL as a dump from sql-lite and import it into mysql) The other way mysql->sqllite should also be possible.

SQLlite is as stable as mysql. Gues writing SQL-code in C should nearly be the same in both API's. From PHP (which is a wrapper for the C API) nearly the same functions exits.

Don't know if sqlite can use index structures as good as mysql which can cope very well with index structures on huge Data (2-3G is huge data)