This function is based on
MyBlob toolbox, and it's used to create test environments starting
from existing databases, copying a fixed number of elements from
eache table of the source database to test one.
I'm not related to the author of MyBlob Toolbox: if you don't like this function it's my fault, not his one.
- conn is the object to connect to sourcedb obtained by myblob_open;
- sourcedb is the name of the source database;
- testdb is the name of the destination database;
- limit is the number of elements you want to copy from each table;
you can set it to 'all' if you want to create an exact copy of the