Best way to clone DB

AFAIK, this is easiest way to do this:

mysqldump SOURCE_DB -u username -p pass | mysql NEW_DB -u username -p password

With this, you do not even need to create SQL files. Assumption is same server though. You can find other examples here: http://dev.mysql.com/doc/refman/5.5/en/copying-databases.html  The --no-data option on the SOURCE_DB allows you to copy structure only. Other options are here: http://dev.mysql.com/doc/refman/5.5/en/mysqldump.html

If you are running phpMyAdmin on that same server, under Operations for each database is a function to copy the current database to a new database.

Dave Baldwin, I want the process to run automatically from PHP code.
MlandaT, About mysqldump, how to write it from PHP code?

Just to throw a spanner here - taking a step back and looking at your design. What is the long term expectation - what if you have a 100 or 1000 clients - are you going to be running that many databases?

Is it not possible to design the application to run off a single database that can support multiple clients such that they are ringfenced from each other?

Thank Julian Hansen for your comment.

But I think in case of 1000 or 100000 client, If I have one DB that serves all of them and saves all of their data, every table will contain massive data, which may affect performance, So I think to save data of each client in his database will be more efficient and quires will be so fast.

You can use the following options:

system: system("mysqldump -h localhost -u ....");
exec: exec("mysqldump -u mysqluser -p my_database | mysq.....");
passthru (requires SAFE_MODE off... so last option)

will be more efficient and quires will be so fast.

That's why databases have indexes - but I leave it to your better judgement ...

Thank u MlandaT, But I want to know ur opinion about the security of using such a command:
exec: exec("mysqldump -u mysqluser -p my_database | mysq.....");

Is there any security threat doing it that way?

Thanks

Thanks for the points but in my view the selected answer is not the correct choice. Mlanda gave you the syntax for cloning the DB - if you are going to use that you should have accepted his answer and possibly selected mine as an assisted.